99 Western Screech-Owls the Hungry Bird—A Shrike Stash Colorado Field Ornithologists PO Box 929, Indian Hills, Colorado 80454 Cfobirds.Org

Vol. 49 No. 4 Fall 2015 Colorado Birds The Colorado Field Ornithologists’ Quarterly

Colorado's Breeding Bird Atlas II Grand Valley CBC—99 Western Screech-Owls The Hungry Bird—A Shrike Stash Colorado Field Ornithologists PO Box 929, Indian Hills, Colorado 80454 cfobirds.org

Colorado Birds (USPS 0446-190) (ISSN 1094-0030) is published quarterly by the Col- orado Field Ornithologists, P.O. Box 929, Indian Hills, CO 80454. Subscriptions are obtained through annual membership dues. Nonprofit postage paid at Louisville, CO. POSTMASTER: Send address changes to Colorado Birds, P.O. Box 929, Indian Hills, CO 80454.

Officers and Directors of Colorado Field Ornithologists: Dates indicate end of current term. An asterisk indicates eligibility for re-election. Terms expire at the annual convention.

Officers: President: Doug Faulkner, Arvada, 2017*, [email protected]; Vice Presi- dent: David Gillilan, Littleton, 2017*, [email protected]; Secretary: Larry Modesitt, Greenwood Village, 2016, [email protected]; Treasurer: Michael Kiessig, Indian Hills, 2017*, [email protected]

Past President: Bill Kaempfer, Boulder, 2016, [email protected] Directors: Christy Carello, Golden, 2016*; Lisa Edwards, Palmer Lake, 2017; Ted Floyd, Lafayette, 2017; Mike Henwood, Grand Junction, 2015*; Christian Nunes, Longmont, 2016*; Chris Owens, Denver, 2018*

Colorado Bird Records Committee: Dates indicate end of current term. An asterisk indicates eligibility to serve another term. Terms expire 12/31.

Chair: Mark Peterson, Colorado Springs, 2018*, [email protected] Committee Members: John Drummond, Colorado Springs, 2016; Peter Gent, Boulder, 2017*; Tony Leukering, Largo, Florida, 2015*; Dan Maynard, xxx, 2017*; Bill Schmok- er, Longmont, 2016; Glenn Walbek, Castle Rock, 2015

Past Committee Member: Bill Maynard Colorado Birds Quarterly: Editor: Peter Burke, [email protected] Staff: Christy Carello, science editor, [email protected]; Christian Nunes, photo editor, [email protected]

Contributors: David Dowell, Dave Leatherman, Tony Leukering, Bill Schmoker Annual Membership Dues (renewable quarterly): General $25; Youth (under 18) $12; Institution $30. Membership dues entitle members to a subscription to Colorado Birds, which is published quarterly. Back issues/extra copies may be ordered for $7.50. Send requests for extra copies/back issues, change of address and membership renewals to [email protected]. Contributions are tax deductible to the extent allowed by law.

166 Colorado Birds Fall 2015 Vol. 49 No. 4 The Colorado Field Ornithologists’ Quarterly Vol. 49 No. 4 Fall 2015

PRESIDENT’S MESSAGE...... 168 Doug Faulkner ABOUT THE AUTHORS...... 170 CFO BOARD MEETING MINUTES...... 172 Larry Modesitt CFO TRIP REPORT...... 174 Mike Henwood ALEXANDER WILSON...... 176 Robert Righter COLOROAD'S BREEDING BIRD ATLAS II...... 180 Lynn Wickersham Vaux's swift: colorado's 499th species..... 183 Brandon Percival FULLY EXPOSED...... 185 Bill Schmoker GRAND VALLEY CBC 2014...... 189 Nic Korte CFO CONVENTION PAPERS...... 197 Christy Carello NEWS FROM THE FIELD: SPRING 2015...... 205 David Dowell 72ND REPORT OF THE CBRC...... 221 Mark Peterson, Bill Maynard COMPUTER MODELING TO IMPROVE FLOCK-SIZE ESTIMATES...... 239 Eastern Alyssa H. Rawinski Screech-Owl, Poudre River, THE HUNGRY BIRD...... 247 Larimer Coun- Dave Leatherman ty, 9 May 2013. Photo by Dave IN THE SCOPE...... 255 Leatherman Tony Leukering PRESIDENT’S MESSAGE

CFO Provides Tools for Colorado Birders

Doug Faulkner What do Short-eared Owl, Red-hooded Tanager, and Pale-naped Brush-Finch have in common? They’re all species that occur in Azuay Province, Ecuador, and they’re all species I did not see this past year. You see, my family and I just spent the past year living in Cuenca, Ecuador. Yes, Ecuador, the country that boasts the highest average number of species per square mile than any other in the world, roughly one species per 60 square miles, and I spent an entire 11 months primed to add a significant number of birds to my life list. Well, almost. Cuenca is a fairly large, modern city with a metropolitan population around 400,000. The city sits at about 8,000 feet elevation in a sprawl- ing Andean valley. Like any city of that size it is more concrete jungle than it is Amazonian rain- Doug Faulkner forest. The species list is paltry with perhaps 20 or so regular species to be found year-round. At least, that’s what it felt like from my experience. So, to do any serious birding I had to leave the city and that’s where I hit a snag. While living in a country the size of Colorado, but boasting around 1,660 species might sound ideal, I found it challenging to go it alone. The birding resources available are limited. Foreign birders rarely have the information they need to travel and bird with confidence by themselves – after all, that’s one reason why the bird guid- ing business is so robust. Sure, I could read about habitat preferences and elevational range limits for a particular species in a field guide or online, but those resources rarely give directions, helpful hints or much narrative describing anything useful to find the species by one- self. Without much for guidance, when I boarded that plane heading back to the States I did so knowing that, to paraphrase a popular gambling saying, I had “left birds on the table.” Now that I’m back in Colorado, I am delighted to have a readily available tool for birding the entire state – CFO’s County Birding website. If you haven’t taken the opportunity to peruse what it has to offer, I encourage you to put down this journal and get online immediately! Conveniently found under the Birding Resources tab

168 Colorado Birds Fall 2015 Vol. 49 No. 4 on the CFO website (www.cobirds.org) or on its own (www.colora- docountybirding.org), this site has everything I wish I’d had in Ecua- dor. In addition to providing species lists for each county, it also has pertinent and useful information about the best birding spots including directions, specific areas to search for target species and available amenities (restrooms, anyone?). And with BirdTrax from eBird, you can learn what other birders have found at that location to help you further prepare. I won’t try to convince you that this past year was anything but wonderful. It’s no secret that Ecuador is a spectacular country with huge birding potential. Going it alone, though, has its challenges. So while Colorado averages just one species per 208 square miles, with the Colorado County Birding website at hand, I’m confident that I won’t be leaving birds on the table.

Snow and Ross’s Geese, North Sterling Reservoir, Logan County, 8 March 2015. Photo by David Dowell

Colorado Birds Fall 2015 Vol. 49 No. 4 169 ABOUT THE AUTHORS

Contributors

News From the Field David Dowell is an outdoor enthusiast based in Longmont. When he isn’t hiking or birding, he’s working as a meteorologist at the NOAA Earth System Research Laboratory in Boulder, trying to make thunderstorm forecasts better.

The Hungry Bird Dave Leatherman is a photographer, entomologist and expert on Colorado birds. He is a regular contributor to Colorado Birds as author of The Hungry Bird. His photographs of birds carry- ing food are of such high quality that many of the invertebrates can be identified to species. He obtained his B.S. from Marietta College and his M.S. from Duke University. When not birding, Dave has been known to occasionally enjoy a night on the town listening to live jazz.

In The Scope Tony Leukering is a freelance ornithologist currently based in Florida. His primary interest in birds is migration, and his work has included nearly 14 years at the Rocky Mountain Bird Ob- servatory. He is a recipient of CFO’s Ron Ryder Award and has authored virtually all of the In The Scope columns for Colorado Birds.

Fully Exposed Bill Schmoker is a middle school science teacher, is extremely active in the birding community and is a frequent photo contributor to Birding and other ABA publications in addition to a wide variety of books, magazines and other media. He authored the Geared for Birding column in the American Birding Asso- ciation’s Winging It newsletter and contributes to birding blogs for both ABA and Leica. He is involved with the ABA Young Birders program as a Camp Colorado and Camp Avocet instruc- tor and photo module judge for the Young Birder of the Year contest. Bill is an eBird reviewer and member of the Colorado Bird Records Committee and is a past president of CFO.

170 Colorado Birds Fall 2015 Vol. 49 No. 4 Featured Authors

Alexander Wilson Robert Righter is co-author of Colorado Birds, Birds of Western Colorado and author of Bird Songs of Rocky Mountain States. He has lived in Colorado for 47 years, 34 of them as a CFO member.

Colorado’s Second Breeding Bird Atlas Lynn Wickersham has worked as an avian ecologist for nearly 20 years, with a focus on reproductive ecology of Neotropical migratory birds. In addition to serving as senior avian ecologist with Animas Biological Studies in Durango, she’s also the State- wide project manager for the Second Colorado Breeding Bird Atlas. She developed a love of nature and birds as an under- graduate at Colorado State University, and has been fortunate to have studied and worked on a variety of bird research projects across the continental U.S. After the The Second Breeding Bird Atlas is published, Lynn has plans to take some much need rest and relaxation and go skiing and birding.

2014 Grand Valley Christmas Count: 99 Western Screech-Owls Nic Korte is a geochemist specializing in groundwater contami- nation issues. He is a former president of Grand Valley Audubon and has been the conservation chairman since the early 1990s. His blog Birds and More can be read at the Grand Junction Daily Sentinel’s webpage: www.gjsentinal.com/blogs_and_more

Computer Modeling to Improve Flock-size Estimates Alyssa H. Rawinski is a freshman at Monte Vista High School in Monte Vista, Colorado. Her paper summarizes her 2015 science fair project titled, Do Certain Traits, Skills or Characteristics Affect Bird Estimating Accuracy, and Can a Computer Model Im- prove Estimating Accuracy? You Can Count on It! She took first place in her division of the San Luis Valley Regional Science Fair and was awarded Best Project for Monte Vista Middle School. She competed in the State Science Fair in Fort Collins, Colo- rado, in 2015 and was invited to the 2015 Intel Science and Engi- neering Fair held in Pittsburgh, Pennsylvania in May 2015 as an observer. Alyssa plays piano and flute and enjoys hiking, camp- ing and crafts and is especially fond of rock hounding: searching for crystals, geodes, mossy agate, petrified wood and fossils.

Colorado Birds Fall 2015 Vol. 49 No. 4 171 CFO BOARD MEETING MINUTES

12 September 2015 Bird Conservancy of the Rockies Headquarters, Barr Lake State Park, Brighton, CO

Larry Modesitt President Doug Faulkner called the September quarterly meeting to order at 11:08 a.m. The board welcomed new board members Michael Kiessig and Chris Owens, and the return of board member Mark Peterson. Other officers present were Vice President David Gil- lilan and Secretary Larry Modesitt. Directors Peter Burke, Christy Carello, Bill Kaempfer and Christian Nunes were present. Directors Lisa Edwards, Ted Floyd and Mike Henwood sent their regrets.

Secretary’s Report: Larry Mode- tigate the financial projections with sitt’s minutes of the 18 April 2015 Lynn. If action is to be taken, Doug board meeting were approved. will poll the board by email.

Treasurer’s Report: Michael Kies- Project Fund and Scholarships— sig’s previously emailed financial state- Christy Carello asked last year’s re- ments for the second quarter of 2015 viewers Catherine Ortega and Na- were approved. Directors reviewed than Pieplow for feedback regarding the application for a Treasurer’s bond the process of approving funding. We for $50,000 of insurance and believed agreed to add the following requests: a that the $99 premium, while inexpen- recommendation from the requestor’s sive, appeared to exclude the events organization, return of the funding if for which we would want insurance. the project is not done and informa- Michael will investigate further. tion regarding previous CFO funding. We agreed that equipment of general Items of Business from the Presi- use beyond project use will not be dent funded, but funds for field assistants, 1. Cobirds Moderator Position. which many grantors do not fund, Todd Deininger has requested to be may be approved. relieved from the position of moderator and Lisa Edwards is seeking a CFO-Western Field Ornithologists replacement. The job of the modera- (WFO) Partnership—Larry Modes- tor is to approve new members’ initial itt reported that WFO, in partnership posts and moderate COBirds content. with CFO, is beginning to plan for a 2. Lynn Wickersham has requested fall convention in 2017. CFO mem- additional funding for the second Col- bers thus will be able to attend both orado Breeding Bird Atlas (CO BBA fall and spring conventions that year. II). The board discussed the request We suggested that WFO be responsible and asked Doug Faulkner to inves- for selecting convention location and

172 Colorado Birds Fall 2015 Vol. 49 No. 4 timing, recruiting speakers, determin- book followers, up 210, or nearly 20 ing food & banquet arrangements and percent in just three months. handling registration. CFO’s would help recruit trip leaders. Certain au- Additional Committee Reports thors of articles in Western Birds have 1. Colorado Birds—Peter Burke requested insertion of Digital Object reported that a number of science Identifiers. The purpose of the DOI is articles will be in the next issue. He to make articles more easily searchable suggested an article, “Where are they and to raise the profile of both authors now?” for past birding spots that no and the magazine. We will investigate longer are great, such as Bonny Reser- applicability for Colorado Birds. voir. 2. Publicity—Ted Floyd reported Bylaws Overview—David Gilli- that the 2015 Convention report, bird lan suggested a review of bylaws to see list and photos are now online. if some aspects are obsolete or could 3. Membership—Lisa Edwards re- become clearer. We agreed to form ported that Colorado Birds circulation an ad hoc committee, with David as is now 568 issues, 43 higher than the chair, and with Bill Kaempfer, Doug same time last year. Faulkner and Larry Modesitt as addi- 4. Nominations & Awards—Doug tional members. Faulkner appointed Chris Owens to succeed Joe Roller as Committee Colorado Bird Records Commit- Chair, with Larry Modesitt and Joe tee (CBRC)—Mark Peterson has Roller agreeing to remain commit- begun as chairman, replacing Doug tee members. The only term-limited Faulkner, who left to become Chair- member of the board is Larry Modesitt. man of CFO. Dan Maynard becomes We agreed it is important to get more the newest committee member. committee participation as a means of meeting new people. CFO Website—David Gillilan re- 5. CFO Field Trips—Mike Hen- ported strong usage for our three web- wood’s trip to the Grand Plateau was sites. An average of 137 people access successful, missing only Northern the CFO website (cobirds.org) daily. Goshawk of eight target birds. Bill We discussed the information on the Kaempfer discussed the Riverside website, and how to make it better. He Reservoir field trip. Since attendance suggested adding field reports and board was not limited, twenty-five people meeting minutes on our website. For braved the brisk northwest wind; our online convention brochure, David none, fortunately, were blown to suggested adding an information page Kansas. Bill also mentioned his two- on our website for people to read before day northeast Colorado trip, limited entering the registration process. to three carloads, which was instead buffeted by a south wind. Notable Social Media Communications— birds were a Red-shouldered Hawk Christian Nunes reported 1,265 Face- and a Sabine’s Gull. The next three-

Colorado Birds Fall 2015 Vol. 49 No. 4 173 car CFO trip will be October 10-11, from both the Lamar Chamber of with Bill Kaempfer and Ted Floyd, Commerce and local birders. beginning at Fox Ranch and target- 2. Ask Me. Chris Owens requested ing a difficult to see bird, Sprague’s and received feedback from conven- Pipit. On Sunday, the group will be tion attendees, and she announced blown by choice to Rock Creek in several improvements. Nebraska. The next meeting will be at 11:00 2016 Lamar Convention Plan- a.m. on November 7, 2015 in Lamar. ning—Doug Faulkner 1. Facilities. CFO’s 2016 conven- President Faulkner adjourned the tion will be May 5–9, 2016 in Lamar. meeting at 4:30 p.m. Doug will scout Lamar next week to determine proposed facilities for the Respectfully submitted, picnic and the motel, and assistance Larry Modesitt, Secretary

CFO TRIP REPORT

June Uncompahgre Plateau Trips

Mike Henwood June 12–14 Weekend Trip A group of seven hardy CFO birders met on Thursday, June 12, at the Columbine Campground near Columbine Pass on the Uncom- pahgre Plateau to spend a weekend birding. We were able to find all our target species (except for Northern Goshawk) during the weekend of birding, and were spared the heavy rains from earlier in the week. Owling on Friday night produced a calling Flammulated Owl plus a Great Horned Owl and another Flam calling during the night at the campground. Three of us went out owling again Saturday night and heard two Flammulated Owls calling plus a Northern Saw-whet Owl doing it’s “saw-whet” call at close range. Two of the folks who stayed at the campground Saturday night witnessed a comedy show featur- ing a young Great Horned Owl that flew toward them and awkwardly attempted to land on a branch, then slipped and did a somersault before righting itself and flying to another branch. Earlier on Saturday evening we watched three Common Nighthawks cruise through the campground at ground level, putting on quite a show as they coursed just above the ground, weaving expertly through the campsites.

174 Colorado Birds Fall 2015 Vol. 49 No. 4 Our five-mile hike on Saturday morning got off to a good start with a singing Fox Sparrow and Orange-crowned Warbler in a willow carr. We left the Divide Road at FS Trail 412 and hiked to Beef Pasture Point and back through a variety of different habitats. Some of the highlights along the way included flushing two male Dusky Grouse, listening to singing Lincoln Sparrows, observing a singing Golden-crowned Kinglet close-up and a brief look at a bear. Ar- riving at Beef Pasture Point, we observed Purple Martins entering and leaving a nest cavity in an aspen. We ate lunch in the area watching Purple Martins and Violet-Green Swallows soaring above us in the open meadow adjacent to the aspen forest. A pair of Red-naped Sapsuckers was delivering food to a cavity in an aspen while a herd of 60-70 elk with calves lounged around a beaver pond. The return trip produced another Dusky Grouse that exploded underfoot to reveal a nest with 8 eggs. A pair of Gray Jays was a pleasant surprise just before returning to the Divide Road. We spent the rest of the afternoon birding our way back to Columbine Campground, making short detours along the way. A highlight was finding a female Three-toed Woodpecker, as well as more Red- naped and Williamson’s Sapsuckers entering nesting cavities. Sunday morning the group drove to the Tabeguache Basin area where we heard Grace’s Warblers. Our patience finally paid off with some good looks at a pair of Grace’s Warblers, a lifer for several folks in the group.

June 20–Driving Trip on the Divide Road A group of five CFO members met in Grand Junction on Saturday, June 20 for a day of driving and birding along the Divide Road over the Uncompah- gre Plateau. We were able to see most of the birds seen by the weekend group the week before, missing only the Three-toed Woodpecker and with only brief looks at flying Purple Martins. At our first stop at Jack’s Canyon, we spotted a hard-to-find Hernandez’s Short-horned Lizard (horny toad). Subsequent stops at Carson’s Hole and the Telephone trail produced Red-naped and Williamson’s Sapsuckers visiting nesting cavities in aspen, as well as Mountain and Western Bluebirds, also visiting nests. We heard singing Grace’s Warblers at the Tele- phone Trail stop and were able to see singing Brewer’s and Vesper Sparrows, Green-tailed Towhees and Western Meadowlarks in the mountain parks thick with shrubs and sage. A large willow carr in a broad valley produced singing Fox Sparrows along with Yellow, Orange-crowned and MacGillivray’s Warblers. Lewis’s Woodpeckers were numerous in the area and provided great looks both perching and fly catching. Our lone Dusky Grouse was seen along the Divide Road and a pair of Sandhill Cranes was seen just before dark standing in a pond near the Escalante SWA west of the town of Delta. Everyone agreed it was a long, yet rewarding day of birding.

Mike Henwood, [email protected]

Colorado Birds Fall 2015 Vol. 49 No. 4 175 Alexander Wilson 1766–1813

Bob Righter Born in Paisley, Scotland, Alexander Wilson spent his first 20 years as a weaver, peddler and a smuggler, yet it was his poetry he was best known for. His youth was spent reading all of the great poets of the time including Milton, Burns, Pope, Bruce, Goldsmith and Virgil. Wilson placed second at a young poet’s contest in Edinburgh. In fact, one of his poems, Watty and Meg, sold a hundred thousand copies, which at the time was considered a whopping success, and even by today’s standards would be considered a great achievement. Ultimately it was a poem that would change the course of his life. Wilson was imprisoned after publishing a satirical poem that detailed the cruel working conditions for weavers in a local mill. He was required to burn the poem in public and was pressured to leave the country. Scotland’s loss was America’s gain, as Wilson would become the New World’s first pre-eminent ornithologist who has been dubbed the “Father of American Ornithology.” “Alexander Wilson, 1766– Wilson departed Ireland on a boat named 1813." Licensed under Pub- the Swift, arriving in New Castle, Delaware, lic Domain via Commons in July 1794. Without a penny in his pocket, he had no idea what to do in America. Making his way to Philadelphia, he serendipitously came across a Red-headed Woodpecker—the most beautiful bird he had ever seen. Little did Wilson realize that he was becoming smitten with the birds of his new homeland.

Living in the New World Wilson found employment as a teacher, and held several positions in New Jersey and Eastern Pennsylvania before settling in the Phila- delphia suburb of Kingsessing. It was there that he met the natu- ralist John Bartram, whom Carl Linnaeus described as “the greatest botanist in the world.” Bartram had traveled the American colonies extensively and established a botanic garden in Kingsessing thought to be the first in America, which is still in existence today. John Bar- tram and his son William encouraged Wilson’s budding interest in birds. It was William who introduced Wilson to the accomplished

176 Colorado Birds Fall 2015 Vol. 49 No. 4 Wilson’s Phalarope

American painter Charles Willson Peale. As a result of Peale’s influence, Wilson learned to paint birds. Bartram and Peale were both early supporters of Linnaean tax- onomy. Wilson had a keen eye for detail, and adopted a style of paint- ing birds that often included important botanical illustrations and/ or taxonomic groupings. In 1806 Meriwether Lewis, newly returned from his epic expedition with William Clark, noted of Wilson’s paint- ings, “that no one in America had painted wildlife with the precision and feeling as Wilson.”

American Ornithology Wilson had a bold vision to illustrate and publish a collection of all the birds of North America. Consulting with a printer, he calculated what it would cost to produce a nine-volume set of books, which he would name American Ornithology. To cover his costs, he determined that he would need to sell 200 subscriptions. Wilson virtually walked his way through New England, often covering 50 miles in a day, and gathered 41 subscribers for a total of $4,920. In fact it has been estimated that in two years Wilson walked 10,000 miles, 1,000 of them with his pet parrot, Polly, on his shoulder. Along the way, Wilson’s stature was rising. One prominent Philadelphian described him as “one of the most remarkable people he had ever known.” Among his early subscribers was none other than Thomas Jefferson. Wilson traveled almost constantly in search of new species of birds and new subscribers to American Ornithology. Outside Wilming- ton, North Carolina, he found a wounded Ivory-billed Woodpecker. Wilson wrapped the bird in his jacket and checked into a hotel hop-

Colorado Birds Fall 2015 Vol. 49 No. 4 177 Wilson’s Warbler

ing he could nurse the woodpecker back to health. While he was eating dinner, the Ivory-billed Woodpecker got loose and destroyed his room. The floor was covered in plaster and there was a hole in the wall the size of a man’s fist. Splinters from a fine mahogany table were scattered everywhere. In February 1810 Wilson headed west. At a stop in Louisville, Kentucky, he responded to an ad in a local paper offering drawing lessons. Intrigued, Wilson arrived at the store and was greeted by a gentleman who spoke with a French accent. The man was impressed with Wilson’s sketches of birds and offered to share some of his own… Thus did Alexander Wilson make the acquaintance of John James Audubon! There is no detailed account of how each felt about this chance encounter, but one can only imagine the shock they must have experienced in learning that they were each chasing the same dream. The encounter was not mentioned in Wilson’s journals and letters, and Audubon made only passing reference to the meeting some years after Wilson’s death. Traveling through Kentucky, Ohio and Tennessee in April, right at the height of eastern warbler migration, Wilson discovered and described six new warbler species: Nashville, Magnolia, Bay-breasted, Cerulean, Kentucky and Bay-breasted. In Shelbyville, Kentucky, Wilson observed a flight of Passenger Pigeons that he estimated at 200 million, stretching for 240 miles. He eventually reached Mis- sissippi, then the western US boundary as the Spanish owned the territories west of the Mississippi River. While on a plantation near Natchez, Mississippi, Wilson came across a wounded hawk that he had never seen before. His attempt to rehabilitate the hawk ended

178 Colorado Birds Fall 2015 Vol. 49 No. 4 with the raptor’s talons sunk deep into Wilson’s hand. The hawk eventually died, but Wilson described the new hawk species, calling it the Mississippi Kite. His description included information about the bird’s diet Wilson learned from a careful dissection of its belly, which was full of insects. This is the earliest known account of the Mississippi Kite’s diet. On August 21 1813 Wilson died of dysentery at the age of 40. He is buried in Old Swedes Church in Philadelphia. During Wilson’s era, 343 species of birds were known to occur in the United States. Some of those may not have been known to Wilson, as they were previously described by European ornithologists and the documentations could very well have been scattered in various European Museums. Wilson’s nine-volume American Ornithology included 264 species, 48 of which were new to science. There are two species that occur regularly in Colorado that include “Wilson” in the vernacular name. Wilson’s Warbler (Cardellina pusilla) was discovered by Wil- son near Cape May, New Jersey. He named it “Green-black-capped Flycatcher” but it was later reclassified by the ornithologist Charles Bonaparte who then renamed it Wilson’s Warbler. Wilson’s Snipe (Gullinago delicata) was first described by Carl Linnaeus in 1758 and given the name Common Snipe. Common snipe would later be split with the Old Word population retaining the name Common Snipe, and the New World population named in Alexander Wilson’s honor.

Further reading: Cantwell, Robert Alexander Wilson, 1961, J. B. Lippincott, Phila- delphia and New York Mearns, Barbara and Richard, Audubon to Xantus, 1992, Academ- ic Press, San Diego, California

Bob Righter, [email protected]

Colorado Birds Fall 2015 Vol. 49 No. 4 179 Colorado’s Second Breeding Bird Atlas

Lynn E. Wickersham Breeding Bird Atlases provide data on species distribution, breeding phenology, habitat use and abundance. Additionally, when they are repeated at regular intervals, Atlases can help researchers detect changes in these variables over time. Breeding Bird Atlases serve as important components of large-scale bird conservation strategies and afford natural resource professionals, academics, educators and birders information with wide-ranging applications, including wildlife management/conservation plans, environmental planning docu- ments, field research, education and birding. Because Breeding Bird Atlases require large-scale, on-the-ground efforts for data collection, most rely primarily on volunteers; thus, Atlases represent some of the best examples of citizen science. The first wave of Breeding Bird Atlases in North America commenced in the 1970s in the northeast. In 1980, formation of the North American Ornithological Atlas Committee (NORAC) provided an organizational framework for atlasing, and new states rapidly initiated Atlases across the continent. To date, more than three-quarters of U.S. states and Canadian provinces have completed a Breeding Bird Atlas. NORAC emphasizes the value of repeating Breeding Bird Atlases at regular intervals, typically 20 years, to assess changes in breeding bird distribution over time (Smith 1990). Currently, about one-quarter of states and provinces have completed, or are working to complete, their second Atlas. Colorado initiated its first Breeding Bird Atlas in 1987, with fieldwork completed in 1995. Biologists and birders joined forces to collect the most comprehensive data on distribution, habitat use, breeding phenology and abundance of Colorado’s avifauna to date. Published in 1998, the 636-page Colorado Breeding Bird Atlas (Kingery 1998), hereafter Atlas I, has been widely used by wildlife and natural resource professionals, educators and birders. Conducted from 2007 to 2012, The Second Colorado Breeding Bird Atlas (Atlas II) marked a 20- year interval from the initiation of Atlas I. Data collection was again driven primarily by volunteers, many of whom also participated in Atlas I. Numerous Atlas volunteers were also members of the Colo- rado Field Ornithologists. The primary objectives of Atlas II were to: 1. Document current distribution of breeding birds in Colorado 2. Assess changes in species distribution 3. Document breeding activities for new Colorado species 4. Increase knowledge of habitat use and breeding phenology

180 Colorado Birds Fall 2015 Vol. 49 No. 4 5. Identify important breeding areas for threatened, endangered, sensitive, rare and secretive species With the help of more than 60 volunteer authors, The Second Colorado Breeding Bird Atlas (Wickersham in prep) is headed for pub-

CHANGE Atlas I Atlas II Both Atlases

Fig. 1. Change in distribution for Black Phoebe from Atlas I (1987–1995) to Atlas II (2007–2012).

CHANGE Atlas I Atlas II Both Atlases

Fig. 2. Change in distribution for Mountain Plover from Atlas I (1987–1995) to Atlas II (2007–2012).

Colorado Birds Fall 2015 Vol. 49 No. 4 181 = Median Date Courtship n=16

Nest Building n=35

Occupied Nest n=21

Nest with Young n=11

Fledged Young n=207

Feeding Fledglings n=112

25-Apr 13-May 31-May 18-Jun 6-Jul 24-Jul 11-Aug 29-Aug

Fig. 3. Breeding phenology data for the Yellow-rumped Warbler during Atlas II (2007–2012).

lication by the close of 2015. The book compares the results of both Atlases and presents data on changes in species distribution over time as well as updated habitat use data and breeding phenology windows, critical to wildlife and land managers across Colorado’s extensive landscape. Highlights of Atlas II include detailed accounts for 262 species; color maps, graphs and illustration; analysis of most frequently reported species per habitat type and comparison of Atlas and Breeding Bird Survey trends across habitat types. Importantly, comparative Atlas data provides evidence for some species expansions, for example Black Phoebe (Sayornis nigricans), as well as some declines, such as Mountain Plover (Charadrius montanus). The in- clusion of change maps in Atlas II illustrates the areas of expansion and contraction and provides a welcome addition to Atlas II (Figs. 1–2). In addition, the conversion of breeding data from tabular to graphic format simplifies the presentation of critical breeding windows (Fig. 3). The Second Colorado Breeding Bird Atlas is now available for pre- order from the project website, cobreedingbirdatlasii.org. Because the Atlas has a limited audience, pre-orders are imperative in determining the print run, and the Atlas Steering Committee will facilitate only one print run. Those interested in purchasing Atlas II are strongly encouraged to do so early to insure they will have access to this valuable resource. In addition to the book, a new Atlas II website will launch immediately following the release of the printed book. Website users

182 Colorado Birds Fall 2015 Vol. 49 No. 4 may query each species for maps, block statistics, and block lists, and conversely, may search all blocks for species reported during the Atlas II period. The Atlas I website has been an indispensable tool for natural resource professionals and birders alike, and Atlas II will continue to serve these users free of charge for years to come.

Acknowledgments Atlas II would not be possible without the tireless efforts of approximately 800 volunteers, and I sincerely thank them all. The Atlas II publication acknowledges all field workers, regional coordinators, technical committee members, records committee members, writers and data management assistants. Though the journey has been long and arduous, I hope that Atlas II will prove as useful as Atlas I and make all project volunteers proud to have participated.

Literature Cited Kingery, H. E. (Ed.). 1998. Colorado Breeding Bird Atlas. Colorado Bird Atlas Partnership and Colorado Division of Wildlife, Denver, CO. Smith, C. R. (Ed.). 1990. Handbook for atlasing North American birds. Vermont Institute of Natural Science, Quechee, VT. Available at http:// www.bsc-eoc.org/norac/index.jsp?targetpg=atlascont. Accessed 6 August 2015. Wickersham, L. W. (Ed.). In prep. The Second Colorado Breeding Bird At- las. Colorado Bird Atlas Partnership and Colorado Division of Wildlife, Denver, CO.

Lynn E. Wickersham, [email protected]

Vaux’s Swift becomes Colorado’s 499th Bird Species

Brandon K. Percival Birding alone on a chilly, sunny Tuesday morning on 28 April 2015, I paused near the Cottonwood Picnic area, which is on the Arkansas River, below Pueblo Reservoir dam in Pueblo County, Colorado. Swallows were everywhere, mostly Violet-green, but there were enough Barn, Cliff, Bank and Tree Swallows to keep it interest- ing. I noticed a small swift flying around with the swallows. Chim- ney Swifts (Chaetura pelagica) breed in downtown Pueblo, though I seldom see them on this part of the river, and usually not before late May or in October.

Colorado Birds Fall 2015 Vol. 49 No. 4 183 This swift looked different to me. Chimney Swifts generally fly higher and tend to make a lot of noise. This swift was silent, flying lower to the ground and it’s wing beat was different. Looking closer, I noted that the bird had a white throat and a somewhat pale rump. Compared to the Violet-green Swallows, the swift’s wing- span appeared shorter. I managed to take a few decent photos of the bird, and one confirmed white throat and pale rump. Excited that I might be looking at a Vaux’s Swift (Chaetura vauxi), I continued to observe and photograph the swift for about ten minutes until it flew out of range. I’ve seen Vaux’s Swift in Wash- ington State, where they’re expected, and a few times in Arizona in migration. Although I didn’t have a field guide with me, I was pretty sure the bird was a Vaux’s Swift. Seeking reassurance, I called Van Truan who confirmed the Vaux’s Swift, below the Pueblo Reservoir characters I’d noted in the field: dam, Pueblo County, 28 April 2015. Photo light throat, pale rump and a little by Brandon K Percival smaller than Chimney Swift with a shorter tail. Unable to relocate the bird, I called Margie Joy, who birds around Pueblo a lot, and let her know to be on the lookout for this swift. Later that morning, I circulated photos of the swift and received feedback from Chris Wood, a native Coloradan and eBird Project Leader, and Dave Siliverman who both agreed that it looked good for Vaux’s Swift. Now confident in the identification, I posted the sighting to COBirds and the CFO Facebook page. I also documented the sighting with the Colorado Birds Records Committee (CBRC). In August 2015, the CBRC voted to accept the sighting, making this first state record for Colorado!

Brandon Percival, [email protected]

Editor’s note: Congratulations to Brandon on this first state record! With the addition of Vaux’s Swift, Colorado’s state bird list now stands at 499…what species will become the state’s 500th and who will find it?

184 Colorado Birds Fall 2015 Vol. 49 No. 4 FULLY EXPOSED

Reaching Birds by Bridge

Bill Schmoker Digital “super zoom” point & shoot cameras have been around for quite a while now, with their extreme zoom range in a small, relatively simple package that appeals to birders seeking an easy and affordable way to document their sightings. Many of these, however, present challenges photographing birds due to issues such as long shutter lag, difficulty autofocusing on small, active subjects and/or underwhelm- ing sensor performance. But in a world where consumer digital cameras even just a few years old could be considered antiques, the latest generation of low-cost cameras contain improvements making them popular among birders. Digital cameras with large zoom ranges and many user-controlled features can be termed Bridge Cameras. This comes from the idea that they bridge the gap between the simpler point-and-shoot cameras and more complex Digital Single-Lens Reflex (DSLR) systems. A bridge camera has an electronic viewfinder and a built-in zoom lens, is fairly compact and reasonably affordable. Even a top-level bridge camera costs less than a birding-friendly DSLR lens alone. Bridge cameras typically have the same or similar shooting modes that a DSLR has (such as manual, aperture priority, shutter priority and program-auto) as well as the ability to control ISO, color balance, exposure compensation, metering and autofocus modes. If you find yourself intimidated or confused by these options, you can take comfort in the ever-available automatic mode that bridge cameras sport. The auto mode works great as training wheels to fall back on, but I would encourage folks with a bridge camera, or DSLR for that matter, to explore and experiment with some of the more advanced modes. The advantages they offer for different shooting situations are well worth the time spent learning how and when to use them. Depending on the make and model, a bridge camera will have some other cool tricks in store such as a palate of creative shooting modes, filters and effects. These aren’t always of great utility for bird photography but add to the versatility of the camera for landscapes and portraits. Not to be underappreciated in the birding arena is the video ability that bridge cameras boast. Their image-stabilization, along with long-lens focal length equivalent (more on that below) and built-in stereo microphones can produce movies that are im- mensely pleasing and tell much more of “the story” than single images often can. For example, here’s a video I made using a bridge

Colorado Birds Fall 2015 Vol. 49 No. 4 185 Steller’s Jay, Wild Basin, Rocky Mountain National Park 24 July 2015. Photo taken with Leica V-Lux (Typ 114). Photo by Bill Schmoker

Wood Stork, Merritt Island NWR, Florida, 23 January 2015. Photo taken with Leica V-Lux (Typ 114). Photo by Bill Schmoker

186 Colorado Birds Fall 2015 Vol. 49 No. 4 camera during this year’s ABA Camp Colorado visit to Allenspark for hummingbird observation: http://bit.ly/1DW5nlD I’ve been putting a bridge camera (Leica V-Lux Typ 114) into extensive use this summer and here are some considerations and tips I’ve rounded up: • Don’t toss your DSLR rig (at least not yet). Bridge cameras are getting more and more amazing, but for the best images a “big rig” still delivers the goods. I like to pick my moments—if I’m out on a concerted photography effort, I’ll tote the big rig. But if I’m doing more general birding, leading a trip or aiming for video work, then I have no hesitation slinging the bridge. • Understand the numbers when it comes to lenses. In the bridge camera world, lenses are often marketed with figures such as “50x op- tical zoom.” This is real, but doesn’t mean 50-times magnification. Rather, it means that it has a ratio of 50 from the most zoomed to the widest setting. For example, on the venerable Canon SX50, the focal length at highest zoom is equivalent to 1200mm and the widest is equivalent to 24mm. Thus, 1200 ÷ 24 = 50x. Still amazing but at 1200mm equivalent the lens maxes out optically at the equivalent to 24 power. (For background on this, see http://bit.ly/1JW4onB.) • Get control of the autofocus area mode. For birds, you’ll want the ability to set the focus point (typically in the center of the frame) not rely on auto focus area selection. If the camera is picking the point, you’ll often end up with things like leaves and twigs in focus, not the bird. • High magnification also magnifies shake. Image stabilizing systems really help, but you’ll also have to rely on technique like stable shooting positions, high shutter speeds (see below) and/or tripod support to get sharp shots at extreme magnification. • Get a handle on shutter priority mode. The higher the magnification and/or the more active the bird, the faster your shutter speed needs to be to get sharp shots. I suggest engaging auto-ISO (which lets the camera adjust the sensor sensitivity for you) and then dialing up the shutter speed to at least 1/1000 or even more if the light allows when shooting at high magnifications and/or fast-moving birds. • Get a handle on aperture priority mode. When you get a wonderful close-up opportunity on a bird, dragonfly, etc., you may be disappointed to find that only part of your subject is in focus. This is because telephoto lenses inherently have a very shallow depth of field. You can counter this by dialing up your f/stop (which decreases the size of the lens aperture), giving you greater depth of field. • Use the electronic viewfinder (the little viewing window) instead of the camera-back monitor for bird photography. It will be

Colorado Birds Fall 2015 Vol. 49 No. 4 187 easier to point the camera on target (like using binoculars) and the camera is generally more stable pressed to your face than it is held out away from your body. • Watch out for digital zoom. What looks good on your camera viewfinder or monitor might not look as good on your computer. I suggest experimenting with this to see what you think still delivers reasonable quality. You can also elect to turn off the digital zoom feature and instead use cropping in post production if you need get tighter on your subject. • Learn thy camera. Read the manual with your camera in hand. If something doesn’t make sense, see if you can figure it out on the camera itself. Otherwise you can always Google the feature with your camera’s model name in the search field and there will likely be vid- eos, third-party reviews or tutorials. You probably won’t end up using all your camera’s features, but you’ll want to have the important stuff at your command to get the most out of a bridge camera. When considering purchasing a bridge camera, do your homework first. As photographic subjects, wild birds can be among the most challenging. Some bridge cameras are really good at bird photography while others don’t quite make the grade. Check birding blogs, social media and word of mouth to see what works well as successive generations of bridge cameras are introduced. Many camera shops offer demo days that allow you to experience different models before purchasing. For instance, the Canon SX50 has a huge following among birders (including our own Ted Floyd) while its successor the SX60 seems to be a disappointment (http://bit.ly/1DW6JNl.) I’ve been so impressed with the Leica V-Lux Typ 114 that I plan to bring it rather than my DSLR on an upcoming Arctic Ocean research cruise due to its compact size and extreme photographic versatility. (Disclaimer: As a member of the Leica Birding Team I have been loaned this camera along with other Leica optics.) There are un- doubtedly other bridge cameras out there that perform well for bird photography. You can share your experiences (and photos!) on the CFO Facebook page.

Bill Schmoker, [email protected]

188 Colorado Birds Fall 2015 Vol. 49 No. 4 2014 Grand Valley Christmas Count: 99 Western Screech-Owls

Nic Korte Introduction Western Screech-Owls are regularly found in 12 US states and typically reported in nearly 150 Christmas bird count (CBC) circles including a few in Canada and Mexico. A review of eBird data con- firms Central Colorado as the Eastern limit of their distribution, with Western Screech-Owls detected in 22 of Colorado’s 64 counties. Just seven of Colorado’s 47 CBC circles reported Western Screech- Owls in 2015 and recent fieldwork (2007-2015) performed for the Colorado Breeding Bird Atlas II (Wickersham 2015) found Western Screech-Owls reported in just 13 of 1745 priority blocks (Table 1)— apparently a significant decrease from Atlas I (1987-1995, Kingery 1998). In contrast, despite being near the eastern extent of the species’ range, the Grand Valley CBC continues to generate one of the highest counts of Western-Screech-Owls in the nation. In 2014, a remarkable 99 birds were recorded, shattering the previous national high count of 66. This article describes how the Grand Junction CBC conducts its Screech-Owl count, and how it manages to sustain the annual high count. Western Screech-Owls were essentially “discovered” in the Grand Valley by the late Rich Levad (Levad 1989, Levad and Korte 2006). His passion for locating the owls resulted in Grand Valley CBC reports with 20-30 Western Screech-Owls, well in excess of the 0-4 reported prior to 1989. Levad kept a list of natural cavities and would call the owls at a few locations in the pre-dawn, and sometimes in the early evening. On the day of the count, while he performed the typi-

Table 1. Comparison of Breeding Evidence for Western Screech-Owls Between Breeding Bird Atlas I and Atlas II in Colorado

Atlas I Atlas II Change 1987-1995 2007-2012 (%) Possible 17 7 -59 Probable 13 3 -77 Confirmed 7 3 -57 Total 37 13 -65

Colorado Birds Fall 2015 Vol. 49 No. 4 189 cal CBC duties, I would visit as many of these locations as possible to tally owls sunning themselves, or to play a call, generating the occasional reply or sometimes a peek from the cavity. It should be noted that unlike other small, cavity nesting owls, Western Screech-Owls rarely respond to scratching the tree with a stick.

Nest-box Program Coincident with the discovery of a healthy Western Screech-Owl population in Mesa County, the human population experienced a rapid increase resulting in significant loss of farm and ranchland. The natural cavities required by the owls were being lost to development at an accelerating rate and the remaining cavities were being lost to decay and old age, with a reduced cohort of aging trees providing re- placements (Fig. 1). Consequent- ly, a program of placing owl boxes was initiated. The program relies on school shop classes to produce the nest boxes and volunteers to place them. Today there are more than 200 nest boxes in the area with the majority located within the Grand Valley CBC Circle. The program was successful and Grand Valley Western Screech-Owls quickly began using the boxes. It’s not uncommon for a box to be occupied the day after placement as male Western Screech-Owls immediately claim them for their territory. Occupan- cy is typically highest in Novem- ber and December when the owls are actively establishing territories and lowest during nesting season when, for the most part, only females reside in boxes. Typically the males roost concealed in nearby vegetation. Although many boxes are used for nesting, Grand Valley Western Screech-Owls continue to utilize suitable natu- Fig. 1. Western Screech-Owl using a box at ral cavities in favor of boxes as has Walker Wildlife Area. Photo by Nic Korte been reported for Eastern Screech-

190 Colorado Birds Fall 2015 Vol. 49 No. 4 Owls (Gehlbach 1994). This observation suggests that many of the areas where boxes are used for nesting would not otherwise be productive for Western Screech-Owls. Two examples are presented to support this observation. Nesting owls were detected annually in the area of Patterson and 27 ½ road in Grand Junction until 1999 when the nest trees and other nearby old trees were removed for real estate development. One of the developed areas, The Knolls, Fig. 2. Western Screech-Owl in a natural cavity retained a small pond and that was removed as part of a restoration project. green space, but no suitable Photo by Jackson Trappett nest trees. Nest boxes were hung in elms and other small trees and have harbored nesting owls ever since. More recently, it was recognized that the small State of Colorado Walker Wildlife Area had extensive habitat suitable for foraging, however, the trees were too small to support nesting. After the instal- lation of nest boxes in 2012, owls were occasionally observed roost- ing for two years, but this year (spring 2015) owls nested (Fig. 2). Owl boxes are checked twice each year, once in late April or May and as many as possible on count day in December. It’s an all- volunteer effort, not a scientific study, nonetheless some generaliza- tions can be made. During December, boxes are used exclusively by Western Screech-Owls. In the spring American Kestrels and Wood Ducks use nearly as many boxes (12-20) as do owls. Starling usage fluctuates, but is significant and is likely underreported. On occa- sion House Sparrows or Northern Flickers have used boxes, but only rarely. Box maintenance is critical. The wood can split and falling limbs frequently damage boxes. One box suffered a direct hit by lighting while occupied by an owl! Wood ducks are a desirable species but they frequently abandon some or all of their eggs. These boxes are typically not reused unless the eggs are removed. Starling usage over multiple seasons also seems to render boxes undesirable for other species.

Colorado Birds Fall 2015 Vol. 49 No. 4 191 Box repair and cleanup is a dirty task that requires dedicated volunteers willing to haul ladders, tools and cleaning supplies into difficult terrain. Detailed notes are collected on each box during CBCs, which helps to direct the volunteers the following spring.

Camera-on-a-Pole Initially, Levad planned an extensive banding program. To assist with monitoring, he designed a camera-on-a-pole so that next boxes could easily be examined in the spring. As we learned more about the owls, we noticed that during the Christmas count, an individual might be observed sunning itself on the Saturday afternoon before count day, and then not only fail to respond to a call the next morning, but also stay inside the hole all day. Since owl behavior is unpredictable, we had the idea to use a camera to check boxes on count day. Experience with closely watched boxes and with subsequent camera use through the years has shown that any box may be used for a night or two—even boxes that might be unsuitable as a nest site. Hence, using the camera to check every box in the circle increased the total count by several owls. As the box program has grown, so has camera use. For the past few years we’ve assigned two teams, each with a back-up camera to prevent downtime in the event of equipment malfunction, solely to the task of checking owl boxes in the daytime. In 2014, this added 19 owls that had not responded to morning callers.

Morning Calling Routes Calling is a relatively easy activity. All one has to do is drive to a destination, stop and listen, play the call, listen some more, and then move to the next stop and repeat. To increase the pre-dawn calling coverage on count day, volunteers were recruited and trained. When- ever possible, new callers were paired with experienced callers as the volunteer base grew. Although owls can respond at any time, our experience taught us that the final hour before dawn yielded the highest calling success. Volunteers are generally willing to sacrifice a little sleep in order to be in place at approximately 5:45 a.m. knowing they’ll be home in time for breakfast. For that reason, the owl count is now managed altogether separately from the CBC itself. Calling for Western Screech- Owls is completed early enough that there is no conflict with the day count with the exception of the two teams using cameras to check boxes. At first calling routes were based on known locations of natural

192 Colorado Birds Fall 2015 Vol. 49 No. 4 cavities. Box locations were avoided because those would be checked with the camera. At the end of the day, the data would be reviewed to eliminate potential double-counts. As more volunteers were recruited, new, more complex routes were needed. Careful study of the CBC circle habitat including many hours of scouting allowed us to plot both the known nesting territories and, based on an understanding of the Western Screech-Owl’s preferences, additional likely locations. Using this technique, new routes were designed and efforts made to recruit additional volunteers to cover them. I’ve learned to give callers a lot of flexibility. Some are willing to wake early and drive sometimes several miles to their assigned route. Others simply walk out their door and call at a few locations in their neighborhood. Initially, I devised calling routes with the sole intent of obtaining maximum coverage of the count circle. I soon realized, however, that the best way to retain volunteers was to ensure that they each had some success. Thus the next iteration of calling routes included as many of the nest boxes that were likely to be occupied as possible, and the result was a happy group of volunteers. A second benefit of this strategy was that it enabled the box camera teams to check more of the low-priority boxes, which led to the detection of owls that otherwise would have been missed. The calling routes inevitably became more difficult to devise and check as years passed. We now rely on mapping software to create routes that combine driving efficiency and known owl locations with a minimum of overlap (Fig. 3). This work is made possible through a partnership with Colorado Mesa University and is managed by a student as part of an independent project. For the 2014 CBC, 19 teams comprised of 51 participants reported 99 Western Screech-Owls. We determined that 34 boxes were occupied on count day (owls seen in or on them) with an additional five probable and 12 possible. In total, the volunteers contributed 112 hours and drove more than 350 miles.

Preparation Meticulous preparation is required to effectively deploy so many volunteers. Each field team is given a route description and whenever possible a detailed map that includes the calling locations. We encourage team leaders to drive their routes in advance at least once during daylight hours, both to gauge time and distance as well as to scout parking locations and determine accessibility, taking into account the possibility of snow on count day. The daytime check allows leaders to preview locations and deter-

Colorado Birds Fall 2015 Vol. 49 No. 4 193 mine if trees have been removed or otherwise altered. Fortunately, many of our leaders have performed the same routes for multiple years. In some cases, their familiarity has led to a sense of ownership and leaders have even suggested adding new box locations or have obtained landowner permission to access new areas. Each route leader is required to report results immediately upon completion of the calling route. My wife stays by the phone with a clipboard recording results from each calling location. I later cross- check the successful sites with the master list of box locations to ensure that these locations aren’t checked with the cameras the next day. By 8 a.m. both camera teams meet at my house to review the final daytime routes. Box-checking usually continues until near dusk. Route leaders are also encouraged to recruit additional riders since more ears generally results in more owls detected. It’s not uncommon for two owls to respond, and on rare occasions three. Additionally, Western Screech-Owls have different responses. One owl may respond with the traditional “bouncing ball” call, while others give an irritated bark. Having multiple observers helps ensure that all owls are counted.

Fig. 3. Example of a route map given to a calling team for the CBC.

194 Colorado Birds Fall 2015 Vol. 49 No. 4 Weather The two highest Grand Junction counts occurred on calm days with heavy, overcast skies. Although hard data is lacking, my experience is that calm days with a bright moon generally elicit the fewest responses. Likewise days with extreme cold, high winds or blowing snow also have been less productive. The only certainty is that owls are unpredictable. I once followed up on a lead that an owl was using a box on my calling route, but there was no response. At first light, I approached the box and found the owl sitting in the hole oblivious to repeated calls.

Community Outreach An unexpected benefit of the program has been the level of public acceptance and interest. At first, outreach was limited to occasional knocks on doors to request permission to install a box in a likely area. Most homeowners have no idea that these small owls live in such close proximity with them. After learning about the birds and experiencing some sightings, many will become fiercely protective of “their” owls. Many times I’ll get a call from their neighbors seeking a nesting box for their property. Perhaps the most satisfying aspect of public outreach has been the many friendly interactions that occur with box owners. Some are el- derly and receive few visitors. Some are simply eager to learn about what’s living in their box. They look forward to the big day when their box is checked and often will invite the volunteer in for a chat and refreshment. It’s gratifying to hear a homeowner say, “I’m always glad to see you coming.” Each spring we hold a public banding day with a licensed bander, assisted by local volunteers, who visit several boxes to band the fledglings and any adult owl that is in the box. Families with children are encouraged to attend and more than 50 showed up in spring 2015. Neighbors and passers-by often take notice of the banding program and associated activities such as box checking and maintenance, providing excellent educational opportunities. Newspaper coverage adds to public awareness of local wildlife.

Summary Until 2014, only four CBCs had reported more than 60 Western Screech-Owls. One of those was a Grand Valley Count and the others were from California in areas with extensive live oak, sycamore and cottonwood habitat. Nonetheless, the desert riparian and agri- cultural areas that exist within Mesa County seem to be particularly suitable for Western Screech-Owls. A multi-decade, multi-faceted

Colorado Birds Fall 2015 Vol. 49 No. 4 195 effort relying on many volunteers has resulted in the identification and augmentation of the locally high population of these birds. A well-coordinated effort of placing and maintaining nest boxes com- bined with extensive communication among volunteers and cooper- ative weather conditions resulted in a national record of 99 Western Screech-Owls detected in 2014.

Acknowledgements All of our work is dedicated to the late Rich Levad. We are proud of the fact that we might have taken this program beyond even his great vision for it. Thanks also to our many dedicated volunteers, without whom this extraordi- nary effort would not be possible.

Literature Cited Gehlbach, F.R., 1994. The Eastern Screech Owl: Life History, ecology, and behavior in the suburbs and the countryside. (W.L. Moody Jr., Natural History Series, No.16), Texas A&M University Press, College Station, Texas. Kingery, H. (Ed.), 1998. Colorado Breeding Bird Atlas I, Colorado Breeding Bird Atlas Partnership/Colorado Division of Wildlife, Denver, CO. Levad, R., 1989. Western Screech-Owls in the Grand Valley. J. Colo. Field Ornithology. 27:131-132. Levad, R., and Korte, N., 2006. Western Screech-Owls of the Grand Valley: Running Up the Score. Colorado Birds, v.40, #2, April 2006. Wickersham, L. E. (Ed.). The Second Colorado Breeding Bird Atlas. Colora- do Bird Atlas Partnership and Colorado Parks and Wildlife, Denver, CO.

Nic Korte, [email protected]

196 Colorado Birds Fall 2015 Vol. 49 No. 4 Annual Convention of the Colorado Field Ornithologists

Salida, Chaffee County, Colorado, June 4–7, 2015 Scientific Paper Session, Saturday, June 6

Christy Carello Amber Carver. Modeling Nest-Survival in Shortgrass Steppe Pas- serines. University of Colorado, Denver, 5598 South Grant Street, Littleton, Colorado 80121; [email protected]. Avian nest survival is influenced to varying degrees by environmental features, some of which can be manipulated and some that are outside our control. Land managers commonly employ habitat manipulation to promote population growth in target species. However, features such as weather that cannot be manipulated may exert equal or greater influence on nest survival. I estimated nest survival for three species of ground-nesting shortgrass steppe passerines in The Scientific Paper Sessions are a high- northern Colorado, and I mod- light of the annual CFO Conventions and this eled survival based on environ- year’s Salida Session was no exception. More mental features of known or sus- than 100 avid birders hung up their binocu- pected importance. I compared lars on Saturday afternoon to enjoy presenta- the applicability of two non-mu- tually-exclusive hypotheses: (1) tions from students, professors and amateur nest survival is strongly influ- ornithologists. Each of the nine presenters enced by weather, and (2) nest was under pressure to keep his/her delivery survival is strongly influenced by under the 15-minute time limit, including nest-site vegetation. listener questions! I coach my students to de- After identifying the most scribe their scientific work using a minimum influential temporal variables, which would account for unmea- of jargon, to accommodate a general audi- sured influences to survival, I fit ence in a manner both understandable and separate sets of weather- and veg- compelling. CFO supports important scien- etation-based models. Weather tific investigation that will further the under- variables exerted equivalent standing and conservation of Colorado birds, moderate influence. Vegetation and five of the presenters were recipients of variables were mostly unimport- ant, except for bare ground and CFO grants. If you missed the paper session dead vegetation. A model con- this year, or just want to refresh your memory, taining both dead vegetation we have compiled the abstracts in this issue and bare ground best explained for your reading pleasure. -C. Carello

Colorado Birds Fall 2015 Vol. 49 No. 4 197 survival, and it was not improved by the addition of weather variables. Nest survival declined with increasing extent of bare ground and dead vegetation. These findings support the idea that habitat manipulation can be used to promote population growth in the nesting phase.

Nora Covy. Canyon Wrens and Cliff Swallows: Observations of and Research on a Local Heterospecific Relationship. School of Biological Sciences, University of Northern Colorado, Ross Hall, Room 2480, Campus Box 92, 501 20th Street, Greeley, Colorado 80639; nora. [email protected]. There is evidence of a locally occurring, heterospecific relationship between a migratory and a non-migratory avian species, based on ongoing research from 2011 through 2015. We have observed Canyon Wrens nesting and foraging in Cliff swallow nests in various locations in Larimer County at different times throughout the year. Canyon Wren occupation of suitable habitat is also positively corre- lated with presence of Cliff Swallow nest colonies. Cliff Swallow nest colonies harbor a variety of ectoparasites and other insects that could serve as a year-round food source for Canyon Wrens, increasing their chances of winter survival in this area. Furthermore, if Canyon Wrens are consuming ectoparasites, this suggests that there may be a mutu- ally beneficial relationship between these two species. In order to better understand this association, we are monitoring the occurrence of Canyon Wrens using Cliff Swallow nests as shelter and foraging locations. Currently, we are assessing the relative abundance of insect prey in Cliff Swallow colonies and collecting wren fecal samples to determine the presence or absence of DNA from Cliff Swallow ectoparasites. This project will be useful in describing behaviors and life history strategies for the Canyon Wren, a low-density, charismatic species, and it will provide novel information about how structures built by one species may influence heterospecific interactions.

Anna M. Mangan1, 2, Liba Pejchar2, and Scott J. Werner3. The Importance of Birds in Colorado’s Apple Orchards: Agents of Pest Con- trol or Fruit Depredation? 1, 3United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Na- tional Wildlife Research Center, 4101 LaPorte Avenue, Fort Col- lins, Colorado, 80521; [email protected]. 2Colorado State University, Department of Fish, Wildlife and Conservation Biology, Campus Delivery 1474, Fort Collins, Colorado 80523. Birds provide important and sometimes irreplaceable functional roles in ecosystems and declining populations can impact ecosystems, agriculture and the economy. Organic fruit farmers face many chal-

198 Colorado Birds Fall 2015 Vol. 49 No. 4 lenges but among the most impactful are insect and animal pests. Or- chard birds have the potential to consume a major apple insect pest, the codling moth (Cydia pomonella), thereby reducing crop damage; however, birds also feed on the fruit. Our research examines these tradeoffs to understand the role of birds in apple orchards, and to help farmers make better-informed management decisions. Specifi- cally, our questions are: (1) which bird species contribute to insect pest control and fruit damage and, (2) what orchard or landscape features contribute to the rate and magnitude of these services and disservices? To answer these questions, we are investigating foraging habits and fruit damage in three organic apple orchards in the North Fork Valley of Colorado. First, to determine the relative importance of fruit- and insect-consuming birds, we are observing the time spent foraging, and quantifying the number of fruits damaged, as well as collecting fecal samples from birds captured in mist-nets. Using ge- netic sequencing, we will determine the occurrence of codling moths in these fecal samples. Second, we are estimating occupancy and density of bird species involved in pest control or fruit depredation. Third, we are using nets to exclude birds from apples and comparing levels of damage by birds and codling moths within and outside these exclosures. Finally, we will integrate these data to compare the rate and magnitude of pest control and damage as a function of location within the orchard, and surrounding land cover. Our findings should help advance understanding of ecological linkages between bird communities and food production in an era of unprecedented interest in the role of nature in human well-being.

Patrick Magee1 and Jonathan Coop2. Effects of Thinning Treatments on Piñon-Juniper Woodland Birds in the Arkansas River Valley. Department of Natural and Environmental Sciences, Western State Colorado University, Gunnison, Colorado 81231; [email protected], [email protected]. Piñon-juniper woodlands are the largest forest type in Colorado hosting at least 70 breeding bird species. Many birds within the piñon-juniper ecosystem are specialists including: Black-chinned Hummingbird, Gray Flycatcher, Piñon Jay, Juniper Titmouse, Be- wick’s Wren and Black-throated Gray Warbler. Recently the Royal Gorge Field Office (RGFO) of the BLM and other partners have thinned piñon-juniper woodlands to reduce potential for intense wildfires. Since 2003, some stands have been thinned with a hy- droaxe (that mulches the wood), whereas others were hand-thinned with chainsaws and subsequently the branches were scattered or piled and burned. How these treated woodlands impact bird communities

Colorado Birds Fall 2015 Vol. 49 No. 4 199 in the RGFO is unknown. We sampled 39 paired plots that each included a treated and control site. We visited each plot three times and conducted 10-minute point counts at each station (four per plot) to determine species composition and occupancy of birds. We also measured a variety of vegetation parameters to determine effects of treatments on habitat composition and structure. In 2014, 67 bird species were recorded at the 232 sample points including five piñon- juniper obligates. More species occupied treated sites than control sites. A multi-scale occupancy analysis is underway to determine if treatments influence the distribution of birds at the landscape scale and the site scale. Lark Sparrows had significantly higher occupancy in treated landscapes and used flatter sites. They occupied 15 percent of untreated piñon-juniper landscapes compared to 92 percent of the treated areas. The piñon-juniper obligate, Black-throated Gray Warbler showed a reversed pattern with higher occupancy in control than treated landscapes, although occupancy was high in both (control=100 percent, treatment=91 percent). Results of this study will inform land managers regarding biological responses to piñon- juniper removal.

Duane Nelson. The Status of Piping Plovers and Least Terns in Colo-

Time Speaker Title of Presentation 1:30-1:35 Christy Carello, session moderator Welcome to the paper session 1:35-1:50 Duane Nelson The Status of Piping Plovers and Least Terns in Colorado 1:50-2:05 Vinson Turco Eavesdropping on other species: Nuances in avian understanding 2:05-2:20 Anna Mangan The importance of birds in Colorado’s apple orchards: Agents of pest control or fruit depredation? 2:20-2:35 Nat Warning The link between tool use and nest construction: A new paradigm 2:35-2:50 Tyler Williams Clark’s Nutcracker seed use and limber pine meta-population dynamics 2:50-3:15 BREAK 3:15-3:30 Patrick Magee Effects of thinning treatments on piñon-juniper woodland birds in the Arkansas River Valley 3:30-3:45 Nora Covy Canyon Wrens and Cliff Swallows: Observations of and research on a local heterospecific relationship 3:45-4:00 Amber Carver Modeling nest-survival in shortgrass steppe passerines 4:00-4:15 Lynn E. Wickersham The second Colorado Breeding Bird Atlas: Final results

200 Colorado Birds Fall 2015 Vol. 49 No. 4 rado. U.S. Army Corps of Engineers and Colorado Parks and Wild- life, 342 East 6th Street, Las Animas, Colorado 81054; dnelson1@ centurytel.net. Protecting federally listed Piping Plovers and Least Terns nesting in Colorado requires the implementation of various management strategies. Habitat loss constitutes the primary threat, manifested by drought and non-native plant invasion to critical habitat. Second- ary threats include depredation, flooding, extreme weather events and human recreational pressure impacting nest sites. Responses to these threats have included creation of nesting islands; mechanical, manual and chemical restoration of nesting habitat and the closure and patrolling of nesting areas to the general public. In 2014 the statewide population of Piping Plovers increased to 10 pairs for the first time since monitoring began in 1990. Least Tern populations in Colorado have decreased, largely due to lakes shrinking or disappear- ing, eliminating much of their former Colorado habitat.

Vinson Turco. Eavesdropping on Other Species: Nuances in Avian Understanding. Department of Biology, Metropolitan State Univer- sity of Denver, Campus Box 53, Denver, Colorado 80217; vturco@ msudenver.edu. Many animals are able to communicate the presence of a potential predator through vocal signaling. It is known that Black-capped Chickadees (Poecile atricapilla) are able to not only advertise the presence of a potential threat but can also indicate varying levels of risk associated with a threat through a complex alarm call. While it has been shown that some birds eavesdrop on the alarm calls of other species, it would greatly benefit heterospecifics living in sympatry with Black-capped Chickadees to understand the degree of danger being communicated as well—fleeing in response to non-urgent calls wastes both energy and time. In this study we performed play- backs of various chickadee alarm calls and measured the response in a number of other bird species to determine which if any are able to discern between the different degrees of urgency being communicated. Songbirds living in close sympatry with Black-capped Chickadees have shown the greatest ability to distinguish between urgent and non-urgent calls with the most urgent calls eliciting the greatest response. Birds were significantly more likely to flee the most urgent alarm over either the less urgent call or the control. Additionally, birds were significantly more likely to exhibit alert or defensive behavior (including but not limited to fleeing) in response to only the most urgent alarm. Although the response of animals to heterospecific alarm calls has been demonstrated, the ability of one

Colorado Birds Fall 2015 Vol. 49 No. 4 201 species to interpret and respond to variations within a call has only recently begun to be explored and has potentially great implications for avian ecology.

Nat Warning. The Link Between Tool Use and Nest Construction: A New Paradigm. City of Longmont, Natural Resources Department, Longmont, Colorado; [email protected]. In studies of evolutionary biology most researchers have assigned tool use in non-humans a special biological distinction, implying that tool users inherently possess high levels of cognitive complex- ity and provide significant insights into the evolution of human culture. Conversely, nest construction behaviors have typically been excluded from discussions of the evolution of tool use because the materials remain static and are not manipulated during use. Increas- ingly though, many scientists are viewing tool use as a form of construction behavior, recognizing that the differences between tool behaviors and construction practices are largely arbitrary. Here I give a brief overview of nest construction behaviors in birds, emphasizing my own research on Rock Wrens (Salpinctes obsoletus), and compare nest building to using tools. I assert that nest building is of equal or greater ecological importance than tool use in animals, and that nest construction behaviors should be placed, with tool use, into the larger context of “material culture.”

Lynn E. Wickersham. The Second Colorado Breeding Bird Atlas: Final Results. San Juan Institute of Natural and Cultural Resources, Fort Lewis College, 1000 Rim Drive, Durango, Colorado 81301; [email protected]. When repeated at regular intervals, Breeding Bird Atlases provide valuable data on changes in bird distribution, habitat use and breeding phenology over time. Fieldwork for Colorado’s first Breeding Bird Atlas (Atlas I) was initiated in 1987, and the results were published in 1998. Atlas I represented the state’s largest and most comprehensive study on breeding birds. Data collection for the second Colorado Breeding Bird Atlas (Atlas II) was initiated in 2007, 20 years after Atlas I, and continued through 2012. In both Atlases, field workers surveyed priority blocks uniformly distributed across the state, encompassing approximately 10 m2. At- las protocol suggested three to five visits per block (~20–40 hours) over the course of one or more breeding seasons, with at least one nocturnal survey for owls and crepuscular species. During each visit, field workers recorded all species detected with associated breeding evidence and habitat codes. Breeding evidence codes

202 Colorado Birds Fall 2015 Vol. 49 No. 4 categorized each species as a Possible, Probable or Confirmed breeder within each block. More than 700 volunteers participated in Atlas II, logging more than 54,000 field hours and recording over 195,000 breeding observations. Field workers spent an average of 28.1 person-hours per priority block, compared with 38.6 in Atlas I. Despite the reduction in effort, Atlas II reported about 14 percent more observations and documented 11 more species than Atlas I. Atlas II field workers reported 14 “new” species (not reported in Atlas I) but failed to document 11 rare species reported in Atlas I. Comparing the number of priority blocks with breeding evidence per species, 56.6 percent of species showed apparent gains, 40.7 percent showed losses and 2.7 percent remained the same. The top five most widely reported species included Mourning Dove, American Robin, Red-tailed Hawk, West- ern Meadowlark and Brown-headed Cowbird. Atlas II data suggests notable range expansions for Wild Turkey, Osprey, Black-chinned Hummingbird, Black Phoebe and Great-tailed Grackle, to name a few, and possible declines for Mountain Plover, Long-billed Curlew, Western Screech-Owl, Lewis’s Woodpecker and Belted Kingfisher.

1 2 Tyler Williams and Diana Tomback . Clark’s Nutcracker Seed 1 Use and Limber Pine Meta-population Dynamics. 901 North Sherman Street, Apartment #708, Denver, Colorado, 80203; Tyler.2.Williams@ ucdenver.edu. 2Department of Integrative Biology, University of Col- orado, Campus Box 171, P.O. Box 173364, Denver, Colorado, 80217- 3364; [email protected]. The Clark’s Nutcracker (Nucifraga columbiana) is an iconic species of the American West because of its importance as a seed disperser of several high-elevation pines including Limber Pine (Pinus flexilis). Its diet consists primarily of conifer seeds. Within Colorado the large seeds of Limber Pine are preferred over other conifer seeds. Limber Pine stands comprise meta-populations—i.e. regional populations composed of local populations subject to extinction, colonization and re-colonization. We are studying how the Limber Pine meta-population in Rocky Mountain National Park (RMNP) is maintained by long-distance seed dispersal (colonization) by the nutcrackers, and how disturbance might lead to local population extinctions. Historically, fire and ecological succession primarily caused local population extinctions, but current threats for the RMNP Lim- ber Pine meta-population include mountain pine beetle (Dendroc- tonus ponderosae) outbreaks, wildfires and White Pine blister rust (a non-native pathogen, Cronartium ribicola). Extensive tree mortality will result in the loss of an important nutcracker food source and

Colorado Birds Fall 2015 Vol. 49 No. 4 203 may reduce nutcracker seed dispersal, complicating meta-population persistence. Our primary goal is to clarify the dynamics of the RMNP Limber Pine meta-population, focusing on the factors that affect colonization. From mid-June to late October 2014, we investigated nutcracker dietary preferences within RMNP by examining 1) Cone production via distance sampling from five Limber Pine stands, three Ponderosa Pine (Pinus ponderosa) stands and three Douglas Fir (Pseudotsuga menziesii) stands: conifers with seeds that nutcrackers routinely use. 2) Nutcracker stand visitation via point counts. 3) Nutcracker seed harvest and caching by focal behavior sampling. This information would identify the conifer species responsible for keeping nutcrackers within RMNP and could serve as a proof of concept that nutcrackers are the primary seed disperser of Limber Pine within RMNP. We have also constructed the RMNP Limber Pine meta-population from GIS layers. The 2014 data indicate that Limber Pine and Ponderosa Pine seed productivity ranged from high to low throughout our study stands, while Douglas Fir productivity was primarily low. Nutcrackers began foraging on Limber Pine in early August and caching of Limber Pine seeds commenced in early September. Nutcracker foraging and caching observations shifted from Limber Pine to Ponderosa Pine in October. No foraging or caching was observed for Douglas Fir. Be- cause both pines do not produce cones every year, together they are a significant resource for nutcrackers and are important for keeping them within RMNP. In 2015 we will radio-track nutcrackers to collect data on nutcracker home range sizes, seed dispersal distances and caching locations for meta-population connectivity information.

Christy Carello, [email protected]

204 Colorado Birds Fall 2015 Vol. 49 No. 4 NEWS FROM THE FIELD

Spring 2015 (March–May)

David Dowell “News from the Field” contains reports of rare birds found in Colorado. These reports are compiled from eBird (ebird.org), the COBirds listserv ([email protected]) and the West Slope Birding Network ([email protected]). The reports contained herein are largely unchecked and the editors do not necessarily vouch for their authenticity. Species in capitals are those for which the Colorado Bird Records Committee (CBRC) requests documentation. Please submit your sightings of these “review” species through the CFO website at coloradobirdrecords.org.

Season Overview Colorado birders will remember spring 2015 for the rain as much as for the birds. Rain fell almost daily in many locations during the first three weeks of May 2015. As a result, Colorado experienced its wettest May in the 121 years of precipitation records dating back to 1895 (www.ncdc.noaa.gov/temp-and-precip/us-maps/1/201505#us- maps-select). Portions of eastern and northeastern Colorado received over 10 inches of rain, which is more than five times the average amount, and western counties also received above normal rainfall. The persistent rains affected where the birds and the birders went. Flooding closed roads and inundated state wildlife areas, particularly

National Oceanic and Atmospheric Administration analysis of May 2015 precipitation (inches) in Colorado and surroundings.

Colorado Birds Fall 2015 Vol. 49 No. 4 205 near rivers such as the South Platte. Crow Valley Recreation Area in Weld, a traditional May hotspot for birders seeking eastern migrants, closed in late May after the intermittent Crow Creek became a river. Birders encountered a few local fallouts in late April and early May during the onset of the rainy period, but more often they reported finding fewer migrating land birds than usual. Nevertheless, the species list compiled from reports across the state in spring 2015 is impressive, and includes 38 warbler species. Alder Flycatchers were reported at 13 locations in eastern Colo- rado in May, with multiple birds found in several locations. The high number of sightings of this species, which is on the state review list, is unprecedented. The first sighting, on May 2, is also earlier than previously accepted records. Noteworthy sightings of individual birds in spring 2015 include Vaux’s Swift in Pueblo, a first state record; Mottled Duck inPueblo , a candidate second state record to be reviewed by the CBRC; Zone- tailed Hawk in Kit Carson (two previously accepted records); West- ern Gull in Delta (four accepted records); Common Ground-Dove in Delta (five accepted records); Painted Redstart inMontrose (seven accepted records); Black-chinned Sparrow in Mesa (six accepted records); California Condors (tagged birds “N8” in Montezuma and “N1” in El Paso); Lucy’s Warbler in Weld, one of only a few records in eastern Colorado; and Yellow-throated Warbler in La Plata, a first record for western Colorado. In the list of reports below, county names are italicized and the following abbreviations are used: CFO – Colorado Field Ornithologists; m.ob. – many observers; MA – Management Area; NM – National Monument; NP – National Park; NWR – National Wildlife Refuge; Res. – Reservoir; SP – State Park; SWA – State Wildlife Area.

BRANT (Black): One at Monte MOTTLED DUCK: One at Lake Vista NWR, Rio Grande, 16 Mar – 27 Beckwith in Colorado City, Pueblo, Apr (Deb Callahan, m.ob.). 10 Apr (David Silverman). Trumpeter Swan: As many as 5 Long-tailed Duck: Reports from near Hayden, Routt, 4 Jan – 6 Mar Alamosa, El Paso, Lake, Larimer, (Nancy Merrill, Tresa Moulton). 1 at Mesa, Park and Weld, 1 Mar – 14 Apr. Fruitgrowers Res., Delta, 9 Mar (Ev- Pacific Loon: One near Nucla, elyn Horn). Montrose, 3 – 6 Apr (Coen Dexter Tundra Swan: Two at Holcim and Brenda Wright). One at High- Wetlands near Florence, Fremont, 15 line Lake SP, Mesa, 23 Apr (Denise Feb - 11 Mar (Rich Miller, m.ob.). and Mark Vollmar). One east of Pueblo, Pueblo, 25 Mar Red-necked Grebe: One at Pueb- (Clark Jones). lo Res., Pueblo, 1 Feb – 22 Apr (Mark

206 Colorado Birds Fall 2015 Vol. 49 No. 4 Peterson, m.ob.). One at Fossil Creek Res., Larimer, 21 Apr (Bobbie Til- mant). One at Barr Lake SP, Adams, 9 May (David Hill, Amy Morton, Karen Drozda, Cynthia Madsen). NEOTROPIC CORMORANT: One near Windsor, Weld, 6 Apr (Steve Mlodinow). BROWN PELICAN: One at St. Vrain SP, Weld, 6 Apr (Dawn Al- bright). Black-crowned Night-Heron: Two hundred at MacFarlane Res., Jackson, Common Black-Hawk, Cottonwood 25 May (Charles Hundertmark). Canyon, Baca County, 14 April 2015. Glossy Ibis: Two at Pastorius Res., Photo by Janeal Thompson La Plata, 1 – 3 May (Susan Allerton, Catherine Ortega, m.ob.); rare in Burlington, Kit Carson, 8 Apr (Riley western Colorado. Five at Red Lion and Heather Morris). SWA, Logan, 16 May (Alec Hopping, Whimbrel: Reports from Bent, David Dowell). Other reports from Crowley, Denver, El Paso, Elbert, Jef- Kit Carson, Larimer, Otero, Washington ferson, Kiowa, Otero, Pueblo and Weld, and Weld, 24 Apr – 18 May. 20 Apr – 18 May. California Condor: One south of HUDSONIAN GODWIT: One Dolores, Montezuma, 16 Apr (Franz at Holbrook Res., Otero, 27 Apr Carver). One in Black Forest, El Paso, (Stanley Oswald). One near Hasty, 31 May. Bent, 4 – 9 May (John Drummond, COMMON BLACK HAWK: Lynne Miller, m.ob.). One at Lower One juvenile at Cottonwood Canyon, Latham Res. and Beebe Draw, Weld, Baca, 13 – 14 Apr (Michael O’Brien, 1 – 8 May (Bob Righter, group led by Brian Gibbons, m.ob.). One adult at Joey Kellner). Pueblo Res., Pueblo, 23 Apr (Brandon RED KNOT: One at John Martin Percival). Res., Bent, 9 May (Nick Komar). Broad-winged Hawk: One at Dunlin: One at Monte Vista Carnero Pass Road, Saguache, 20 NWR, Rio Grande, 17 May (Heidi May (John Cobb); rare in western Retherford); rare in western Colora- Colorado. Other reports from Adams, do. Other reports from Adams, Bent, Arapahoe, Baca, Bent, Boulder, Den- Crowley, Denver, Kiowa and Weld, 1 ver, Douglas, El Paso, Elbert, Fremont, Mar – 17 May. Jefferson, Kiowa, Kit Carson, Larimer, Laughing Gull: One adult in La- Lincoln, Logan, Montrose, Phillips, mar, Prowers, 26 Apr (Dave Leather- Prowers, Pueblo, Sedgwick, Washing- man). One adult at Boyd Lake SP, ton, Weld and Yuma, 4 Apr – 31 May. Larimer, 20 May (Nick Komar). ZONE-TAILED HAWK: One in Mew Gull: One at Windsor Lake,

Colorado Birds Fall 2015 Vol. 49 No. 4 207 Dusky Grouse, Lookout Mountain, Jef- Snowy Plover, Sweetwater Reservoir, ferson County, 25 March 2015. Photo Kiowa County, 20 April 2015. Photo by Janeal Thompson by Dave Leatherman

Weld, 11 Mar (Mark Minner-Lee). BLACK-BILLED CUCKOO: One at Seeley Res., Weld, 11 Mar One at Chico Basin Ranch, El Paso, (Steve Mlodinow). One at Marston 25 May (Brandon Percival). Res., Denver, 18 Mar (Alec Hopping). Boreal Owl: Reports from Delta, WESTERN GULL: One at Fruit- Jackson, Mesa, Routt and Summit, 6 growers Res., Delta, 9 May (Leo Mill- Mar – 27 May. er). VAUX’S SWIFT: One at Pueblo ICELAND GULL (Kumlien’s): Res., Pueblo, 28 Apr (Brandon Per- One at South Platte River near cival); first state record. Thornton, Adams, 6 – 8 Mar (David RUBY-THROATED HUM- Dowell, m.ob.). One sub-adult Ice- MINGBIRD: One at Stulp Ranch land/Thayer’s at Prewitt Res., Wash- near Lamar, Prowers, 4 – 5 May (Jane ington, 8 Mar (group led by Joey Kell- Stulp, m.ob.). ner). one at Jackson Res., Morgan, 20 Calliope Hummingbird: One in Apr (David Dowell). Grand Junction, Mesa, 24 Apr (Ron GLAUCOUS-WINGED GULL: Lambeth); a rare sighting in spring in One immature at Black Hollow Res., Colorado and a very early arrival. Weld, 11 Mar (Steve Mlodinow). ACORN WOODPECKER: One One immature at Lower Latham Res., in Colorado Springs, El Paso, 20 Dec Weld, 16 Apr (Nick Moore, Steve – 7 Mar (Marty Wolf, m.ob.). Mlodinow). Yellow-bellied Sapsucker: One at ARCTIC TERN: One at Tim- Lamar Community College and Wil- nath Res., Larimer, 24 – 29 May (Da- low Creek Park, Prowers, 14 – 28 Mar vid Wade, Austin Hess, Nick Komar, (Glenn Walbek, Mark Peterson, Da- m.ob.). vid Tønnessen, m.ob.). One at Wray COMMON GROUND-DOVE: Fish Hatchery, Yuma, 21 Mar (David One in Paonia, Delta, 13 May (Jason Bea- Dowell). One at Stulp Ranch near La- son); second western Colorado record. mar, Prowers, 31 Mar (Jane Stulp).

208 Colorado Birds Fall 2015 Vol. 49 No. 4 Mountain Plover, CR 38 near Holly, Hudsonian Godwit, Verhoeff Ditch, Prowers County, 23 April 2015. Photo Hasty, Bent County, 4 May 2015. by Janeal Thompson Photo by Janeal Thompson

GYRFALCON: One near Glade (Steve Mlodinow, Steve Larson, Van Park, Mesa, 10 Mar (Mike Henwood, Remsen). One at Flagler Res. SWA, Eileen Cunningham). Kit Carson, 22 – 29 May (Glenn Wal- EASTERN WOOD-PEWEE: One bek, m.ob.). One at Lee Martinez at Stulp Ranch near Lamar, Prowers, Park in Fort Collins, Larimer, 24 May 8 May (Jane Stulp). One at Fountain (Nick Komar). As many as 3 in Ovid, Creek Regional Park, El Paso, 19 May Sedgwick, 24 – 25 May (Steve Larson, (Bill Maynard). One near Loveland, Steve Mlodinow, Van Remsen, Wil- Larimer, 22 May (Sean Walters). One liam Kaempfer, David Dowell). As at Lamar Community College, Prowers, many as 2 at Lion’s Club Fishin’ Hole 26 May (Dorothy Russell). in Holyoke, Phillips, 24 – 25 May (Da- YELLOW-BELLIED FLYCATCH- vid Dowell, William Kaempfer). One ER: One in Florence, Fremont, 21 May at Sand Draw SWA, Sedgwick, 24 May (Brandon Percival). One at Holyoke (Steve Larson, Steve Mlodinow, Van Cemetery, Phillips, 23 May (Steve Lar- Remsen). One at Cherry Creek SP, son, Steve Mlodinow). Arapahoe, 24 May (Glenn Walbek, ALDER FLYCATCHER: One Gene Rutherford, Alec Hopping). near Laird, Yuma, 2 May (Sue Riffe, One at Chico Basin Ranch, Pueblo, David Dowell). One at Prewitt Res., 25 May (Alec Hopping, Brandon Per- Logan, 15 May (Joey Kellner, Kathy cival, Norm Lewis). One at DePoorter Mihm Dunning, Norman Erthal, Alec Lake in Julesburg, Sedgwick, 25 May Hopping). One near Eads, Kiowa, 20 (William Kaempfer, David Dowell). May (Steve Mlodinow, Steve Larson, One at Glenmere Park in Greeley, Van Remsen). Two at Hale Ponds in Weld, 27 May (Steve Mlodinow). South Republican MA, Yuma, 21 May Vermilion Flycatcher: One male

Colorado Birds Fall 2015 Vol. 49 No. 4 209 Stilt Sandpiper, Valco Ponds, Pueblo Eastern Phoebe, Cottonwood Canyon, County, 2 May 2015. Photo by Janeal Baca County, 14 April 2015. Photo by Thompson Janeal Thompson near Pueblo Res. in Rock Canyon, very rare west of the Front-Range Pueblo, 5 Apr (Pearl Sandstrom- mountains. Smith, Cliff Smith, m.ob.). One fe- Yellow-throated Vireo: One at male at Cherry Creek SP, Arapahoe, Roselawn Cemetery near Pueblo, 21 Apr (Cheri Phillips). Pueblo, 2 May (Brandon Percival). Scissor-tailed Flycatcher: One at One at Fountain Creek Regional Chatfield SP,Douglas , 1 May (Paul Park, El Paso, 3 May (David Tønnes- Schlagbaum, m.ob.). One in Walsh, sen, Mark Peterson). One at Lamar Baca, 5 – 18 May (Janeal Thompson, Community College, Prowers, 5 – 9 Jane Stulp, Gene Rutherford). One May (Brandon Percival, group led by at Cherry Creek SP, Arapahoe, 5 – 12 William Kaempfer). One at Picture May (Steven Kennedy, m.ob.). One Canyon, Baca, 10 May (Tom Thom- at Clear Springs Ranch south of Foun- son, Mark Amershek, Scott Manwar- tain, El Paso, 14 May (Aaron Driscoll, ing, Austin Hess). Three at Welches- Mark Peterson, Peter Gaede). One ter Tree Grant Park near Golden, near La Veta, Huerfano, 30 May (Polly Jefferson, 15 May (Robert Martinez). Wren and Paul Neldner). One at Flagler Res. SWA, Kit Car- White-eyed Vireo: One at Lamar son, 18 May (Glenn Walbek). 1 at Community College, Prowers, 25 Apr Prospect Ponds Natural Area in Fort – 2 May (Glenn Walbek, Mark Peter- Collins, Larimer, 20 May (Sue Riffe). son, m.ob.). One at Barr Lake SP, Ad- One at Salyer, McMurry and Magpie ams, 2 – 3 May (Adam Vesely, m.ob.). Meander Natural Areas in Fort Col- One at DeWeese Res., Custer, 30 Apr lins, Larimer, 20 May (Sue Riffe). One (Rich Miller) and 1 at Pike’s Stock- at Crow Valley Campground, Weld, 16 ade, Conejos, 27 May (Lisa Rawinski); – 20 May (Josh Bruening, Derek Hill,

210 Colorado Birds Fall 2015 Vol. 49 No. 4 Black Phoebe, Boulder Creek and 75th Scissor-tailed Flycatcher, two miles east of St, Boulder County, 6 April 2015. Pho- La Veta on CR 358, Huerfano County, 3 to by David Dowell May 2015. Photo by Polly Wren Neldner m.ob.). One at Lions Park in Laporte, Carolina Wren: One near Higbee, Larimer, 22 May (Nick Komar, David Otero, 5 Apr (David Dowell). Wade). One at Chatfield SP,Jefferson , Veery: Reports from Arapahoe, 22 May (Loch Kilpatrick, David Sud- Baca, Bent, Boulder, El Paso, Larimer, djian). One at Rocky Mountain NP, Lincoln, Phillips, Prowers, Pueblo, Sedg- Larimer, 26 May (PJ Ross). wick, Washington, Weld and Yuma, 6 – Blue-headed Vireo: One at Two 30 May. Buttes SWA, Baca, 3 May (group Gray-cheeked Thrush: One in Ar- led by Joey Kellner). One in Colo- riba, Lincoln, 28 Apr (Glenn Walbek). rado Springs, El Paso, 10 May (David One at Chico Basin Ranch, Pueblo, 9 Tønnessen). One at Welchester Tree May (Michele Steber). One in rural Grant Park near Golden, Jefferson, 23 Arapahoe, 11 May (Gene Rutherford). May (Mark Chavez). One at Crow Valley Campground, Philadelphia Vireo: One at Chat- Weld, 11 May (Steve Mlodinow). field SP,Jefferson , 23 May (Renee and One at Melody Tempel Grove, Bent, Jesse Casias). 11 May (John Drummond). One near Winter Wren: As many as 3 at Simla, Elbert, 11 May (David Sud- Brush SWA, Morgan, 28 Feb – 21 Mar djian). One in Cañon City, Fremont, (David Dowell, m.ob.). One at Two 16 May (John Drummond, Brandon Buttes SWA, Baca, 21 Mar (Joey Kell- Percival). ner, Kathy Mihm Dunning, Tim Smart, Swainson’s Thrush (Russet- Norman Erthal). One at Chatfield SP, backed): One at Melody Tempel Douglas, 22 Mar (Joey Kellner, David Grove, Bent, 19 May (Steve Mlodi- Suddjian). One at Rocky Mountain now). One in Boulder, Boulder, 21 NP, Larimer, 23 May (James Nelson). May (Nick Moore).

Colorado Birds Fall 2015 Vol. 49 No. 4 211 Cassin’s Kingbird, Boulder Open Space, Yellow-throated Vireo, Fountain Creek Boulder County, 22 May 2015. Photo Regional Park, El Paso County, 3 May by Peter Burke 2015. Photo by Bill Maynard

Wood Thrush: One at Flagler Res. El Paso, 2 May (Susan Luenser, Gloria SWA, Kit Carson, 8 May (Joey Kell- Nikolai). One at Sinton Pond in Col- ner, Norman Erthal, Charles Law- orado Springs, El Paso, 13 – 16 May rence, Kathy Mihm Dunning, Cheryl (Dan Stringer, m.ob.) One at Brett Teuton). One at Chico Basin Ranch, Gray Ranch, Lincoln, 15 – 30 May El Paso, 20 May (Richard Bunn, John (Glenn Walbek, Peter Gaede, Mark Drummond, Bill Maynard). One in Peterson, Kathy Mihm Dunning). Fort Collins, Larimer, 30 May (Greg One at Prewitt Res., Washington, 17 Levandoski). May (David Dowell). One at Salyer, Gray Catbird: Forty-eight at Brett McMurry and Magpie Meander Natu- Gray Ranch, Lincoln, 22 May (Kathy ral Areas in Fort Collins, Larimer, 19 Mihm Dunning, Joey Kellner). – 20 May (David Wade, m.ob.) Curve-billed Thrasher: One at Blue-winged Warbler: One at Fla- Confluence Park in Delta,Delta , 15 gler Res. SWA, Kit Carson, 28 Apr May (Andrea Robinsong); rare in (Glenn Walbek). One at Welchester western Colorado. Tree Grant Park near Golden, Jeffer- Chestnut-collared Longspur: A son, 13 May – 17 June (Mark Chavez, whopping 1,875 near Genoa, Lincoln, m.ob.). 15 Apr (Glenn Walbek). GOLDEN-WINGED WARBLER: McCown’s Longspur: Three near One at Main Res. in Lakewood, Jef- Rabbit Ears Pass, Routt, 17 Apr (An- ferson, 25 Apr (Art Hudak, Alec Hop- drew Spencer); rare in western Colo- ping). One in Cañon City, Fremont, rado. 16 – 21 May (Robb Hinds, Brandon Worm-eating Warbler: One at Pi- Percival). One at Flagler Res. SWA, Kit nello Ranch near Colorado Springs, Carson, 16 May (Peter Gaede, Mark Pe-

212 Colorado Birds Fall 2015 Vol. 49 No. 4 Dunlin, South Platte River, Adams County, 6 March 2015. Photo by Da- Least Tern, Northgate Reservoir, Prow- vid Dowell ers County, 2 May 2015. Photo by Ja- neal Thompson

Yellow-billed Cuckoo, Northern Colo- Short-eared Owl, Bar 10 Road, El Paso rado Environmental Learning Center, County, 6 May 2015. Photo by Bill Larimer County, 21 May 2015. Photo Maynard by Dave Leatherman

Gray Flycatcher, Ryssby Church, Boul- Golden-crowned Kinglet, Stulp’s Farm, der County, 22 May 2015. Photo by Prowers County, 2 April 2015. Photo Peter Burke by Janeal Thompson

Colorado Birds Fall 2015 Vol. 49 No. 4 213 Northern Mockingbird, CU East Cam- Prothonotary Warbler, Chico Basin pus, Boulder County, 24 May 2015. Ranch, El Paso County, 29 May 2015. Photo by Peter Burke Photo by Bill Maynard

Magnolia Warbler, Chico Basin Ranch, El Paso County, 18 May 2015. Photo Chestnut-sided Warbler, Chico Basin by Bill Maynard Ranch, Pueblo County, 11 May 2015. Photo by Bill Maynard

Black-throated Blue Warbler, Hanover Blackpoll Warbler, Pioneer Park, Ster- Road, El Paso County, 30 May 2015. ling, Logan County, 20 May 2015. Photo by Bill Maynard Photo by Dave Leatherman

214 Colorado Birds Fall 2015 Vol. 49 No. 4 Mourning Warbler, Chico Basin Ranch, El Paso County, 18 May 2015. Photo by Bill Maynard

Kentucky Warbler, Lamar Community Summer Tanager, Northern Colorado College Woods, Prowers County, 23 Environmental Learning Center, Lar- April 2015. Photo by Janeal Thompson imer County, 26 May 2015. Photo by Dave Leatherman

American Redstart, South Mesa Trail- Northern Parula, Stulp Farm, Prowers head, Boulder County, 22 May 2015. County, 29 April 2015. Photo by Dave Photo by Peter Burke Leatherman

Colorado Birds Fall 2015 Vol. 49 No. 4 215 Rose-breasted Grosbeak, Melody Tem- ple’s Grove, Bent County, 28 April 2015. Photo by Dave Leatherman

Bobolink, Reservoir Ridge, Fort Collins, Larimer County, 17 May 2015. Photo by Janeal Thompson

Painted Bunting, Clear Spring Ranch, El Paso County, 3 May 2015. Photo by Bill Maynard

Orchard Oriole, Chico Basin Ranch, El Purple Finch, 6th Street, Las Animas, Paso County, 25 May 2015. Photo by Bent County, 4 March 2015. Photo by Bill Maynard Janeal Thompson

216 Colorado Birds Fall 2015 Vol. 49 No. 4 terson, Kara Carragher, Lisa Edwards). May (Duane Nelson). One at Lamar One hybrid with Blue-winged Warbler Community College, Prowers, 11 May (“Brewster’s Warbler”) near Loveland, (Dorothy Russell). One near Agate, Larimer, 21 May (Sean Walters, David Elbert, 11 May (David Suddjian). One Wade, Austin Hess, Denise Bretting). at Salyer, McMurry and Magpie Me- One at Butterfly Woods Natural Area ander Natural Areas in Fort Collins, in Fort Collins, Larimer, 23 May (John Larimer, 19 – 21 May (Dave Leather- Shenot). man, m.ob.). One at Chico Basin Black-and-white Warbler: Reports Ranch, El Paso, 20 – 25 May (John from Arapahoe, Baca, Bent, Douglas, Drummond, m.ob.). El Paso, Elbert, Jefferson, Kit Carson, Kentucky Warbler: One at Lamar Larimer, Lincoln, Prowers and Pueblo, Community College, Prowers, 23 Apr 1 – 29 May. (Jeannie Mitchell, Aaron Shipe). One Prothonotary Warbler: One at at Stulp Ranch near Lamar, Prowers, Picture Canyon, Baca, 9 – 10 May 31 May (Jane Stulp) (group led by William Kaempfer, Hooded Warbler: One female at m.ob.). One at Lamar Community Chico Basin Ranch, El Paso/Pueblo, 29 College, Prowers, 11 – 23 May (Janeal Apr – 27 May (Nancy Gobris, m.ob.). Thompson, Jane Stulp, m.ob.). One at One at Melody Tempel Grove, Bent, Chico Basin Ranch, El Paso, 28 – 29 8 – 10 May (group led by William May (Victoria Wheeler, Anton Morri- Kaempfer). One male south of Limon, son, Brandon Percival, Richard Bunn, Elbert, 18 May (David Suddjian). Lisa Edwards). CAPE MAY WARBLER: One Tennessee Warbler: Reports from female at Lake Hasty in John Martin Adams, Arapahoe, Baca, Boulder, El Res. SP, Bent, 6 – 11 May (Brandon Paso, Elbert, Jefferson, Kit Carson, Lar- Percival, Gene Rutherford, Nick Ko- imer, Lincoln, Logan, Phillips, Prowers, mar, Jeannie Mitchell, John Drum- Pueblo, Sedgwick, Weld and Yuma, 26 mond). Apr – 26 May. Northern Parula: One near Cres- Orange-crowned Warbler: One tone, Saguache, 14 May (John Cobb). hundred ninety-one at Flagler Res. One at Loudy-Simpson Park near SWA, Kit Carson, 26 Apr (David Craig, Moffat, 17 May (Tom and Kay Dowell). McConnell). One near Gunnison, LUCY’S WARBLER: One at Gunnison, 25 May (Tasha Blecha); Eaton Cemetery, Weld, 10 – 14 May rare in western Colorado. Other re- (Dave Leatherman, m.ob.). ports from Arapahoe, Baca, Bent, Boul- Nashville Warbler: Reports from der, Douglas, El Paso, Elbert, Huerfano, Arapahoe, Baca, Cheyenne, El Paso, Jefferson, Kiowa, Kit Carson, Larimer, Elbert, Jefferson, Kit Carson, Montezu- Lincoln, Phillips, Prowers, Pueblo and ma, Prowers and Pueblo, 15 Apr – 22 Weld, 21 Apr – 26 May. May. Magnolia Warbler: Reports from MOURNING WARBLER: One Arapahoe, Bent, Boulder, El Paso, El- at Melody Tempel Grove, Bent, 8 bert, Jefferson, Larimer, Lincoln, Prow-

Colorado Birds Fall 2015 Vol. 49 No. 4 217 Prairie Warbler, Chico Basin Ranch, El Paso County, 29 April 2015. Photo by Bill Maynard Bell’s Vireo, Valco Ponds, Pueblo County, 31 May 2015. Photo by Bill Maynard Black-throated Blue Warbler: Singles at Melody Tempel Grove, ers, Pueblo, Washington, Weld and Bent, 4 May (Brandon Percival) and Yuma, 15 – 31 May. 19 May (Duane Nelson). One at Blackburnian Warbler: One Stulp Ranch near Lamar, Prowers, northwest of Kit Carson, Cheyenne, 1 7 May (Jane Stulp). One at Lamar May (group led by Joey Kellner). One Community College, Prowers, 9 May at Stalker Lake near Wray, Yuma, 2 (group led by William Kaempfer, Nick May (Sue Riffe). One at Navajo Res., Komar). One at Fort Lupton, Weld, 9 Archuleta, 21 May (James Beatty); May (Jan DeSanti). One at Fountain very rare in western Colorado. Creek Regional Park, El Paso, 10 May Chestnut-sided Warbler: One (group led by Ken Pals and Ted Floyd). at Loudy-Simpson Park near Craig, One at Chatfield SP,Douglas , 12 May Moffat, 21 May (Jan Leonard) and 1 (David Suddjian). Singles in Colo- in Durango, La Plata, 24 May (Susan rado Springs, El Paso, 21 May (David Allerton, James Beatty, Riley Morris); Tønnessen) and 25 May (Gail Baker). rare in western Colorado. Other re- One along Hanover Road near Chico ports from Arapahoe, Denver, El Paso, Basin Ranch, El Paso, 30 May (Rich- Elbert, Fremont, Jefferson, Kiowa, ard Bunn, Brandon Percival). Kit Carson, Larimer, Logan, Prowers, Palm Warbler: Reports from Arap- Pueblo and Yuma, 6 – 30 May. ahoe, Baca, Bent, Boulder, Denver, El Blackpoll Warbler: Reports from Paso, Elbert, Kit Carson, Lincoln, Mor- Arapahoe, Baca, Bent, Boulder, Broom- gan, Prowers and Pueblo, 25 Apr – 20 field, El Paso, Elbert, Jefferson, Kiowa, May. Kit Carson, Larimer, Lincoln, Logan, Pine Warbler: One in Pueblo, Morgan, Phillips, Prowers, Pueblo, Pueblo, 17 Mar (Van Truan). One at Sedgwick, Washington, Weld and Yuma, Barr Lake SP, Adams, 20 May (Chris- 2 – 29 May. topher Rustay).

218 Colorado Birds Fall 2015 Vol. 49 No. 4 Yellow-throated Warbler: One in adult, present for its fifth consecutive Durango, La Plata, 6 – 11 May (Kris- winter, at Teller Farm and Lakes, Boul- ti Dranginis, Andrea Avantaggio, der, 30 Oct – 18 Apr (David Dowell, m.ob.); first western Colorado record. m.ob.). One adult, present for its sixth PRAIRIE WARBLER: One at winter, at Red Rocks Park, Jefferson, 1 Chico Basin Ranch, El Paso, 29 Apr – Nov – 8 Mar (Cyndy Johnson, m.ob.). 3 May (Nancy Gobris, m.ob.) One at Running Deer and Cotton- Townsend’s Warbler: Reports wood Hollow Natural Areas, Larimer, from Denver, El Paso, Elbert, Fremont, 8 Mar (David Wade). Jefferson, Kit Carson, Lincoln, Mon- Summer Tanager: Reports from tezuma, Park, Prowers, Pueblo and Baca, Bent, Boulder, El Paso, Elbert, Washington, 26 Apr – 20 May. Kiowa, Kit Carson, Larimer, Lincoln, Black-throated Green Warbler: Montezuma, Phillips, Pitkin, Prowers, One at Melody Tempel Grove, Bent, Pueblo and Routt, 1 – 29 May. 1 – 4 May (group led by Joey Kellner, Scarlet Tanager: One male in Col- m.ob.). As many as 2 at Brett Gray orado Springs, El Paso, 22 May (Sha- Ranch, Lincoln, 13 – 18 May (Steve ron Milito). One male near Milliken, Mlodinow, Mark Peterson, Peter Weld, 27 May (Steve Mlodinow). One Gaede). One at Chico Basin Ranch, male near Limon, Elbert, 31 May (Da- El Paso, 25 May (Brandon Percival). vid Suddjian). PAINTED REDSTART: One at Black-headed Grosbeak: Forty- Black Canyon of the Gunnison NP, five at Pryor (Santa Clara Creek), Montrose, 15 Apr (Matthew DeSaix). Huerfano, 24 May (Richard Taylor). EASTERN TOWHEE: One first- Painted Bunting: One female at year male at Tamarack Ranch SWA, Clear Springs Ranch, El Paso, 3 May Logan, 3 Jan – 14 Mar (Steve Lar- (Steve Brown, m.ob.). Male and fe- son, Loch Kilpatrick, Glenn Walbek, male pair at Picture Canyon, Baca, m.ob.); possibly a hybrid with Spotted 9 – 10 May (group led by William Towhee. One female at Chico Basin Kaempfer, m.ob.). One female at Ranch, El Paso, 11 Apr (John Drum- Brett Gray Ranch, Lincoln, 15 May mond). One female at Fox Ranch, (Brandon Percival). One male near Yuma, 21 May (Steve Larson, Steve Limon, Elbert, 11 May (David Sud- Mlodinow). One female at Brush djian). Two males at Picture Canyon, SWA, Morgan, 25 May (David Dow- Baca, 18 May (Steve Larson, Van ell). Remsen, Steve Mlodinow). One male BLACK-CHINNED SPAR- at Cottonwood Canyon, Baca, 18 May ROW: One at Colorado NM, Mesa, 2 (Steve Mlodinow, Steve Larson). One May (Forrest Luke, John Weier, Garry female at Pueblo Res., Pueblo, 24 May Budyk). (Brandon Percival). BAIRD’S SPARROW: One at Bobolink: Forty-eight in Cañon Pueblo Res. SWA, Pueblo, 16 Apr City, Fremont, 19 May (Rich Miller). (Brandon Percival). Rusty Blackbird: Two at Sand- Golden-crowned Sparrow: One stone Ranch, Weld, 1 Mar (Chris

Colorado Birds Fall 2015 Vol. 49 No. 4 219 Worm-eating Warbler, Prewitt Res- Ovenbird, Skunk Canyon, Boulder ervoir, Washington County, 17 May County, 17 May 2015. Photo by Peter 2015. Photo by David Dowell Burke

Knight, Kathy Mihm Dunning). cerville, San Miguel, 24 Apr – 1 May Forty-five near Longmont,Weld , 2 (Judy Kennedy, m.ob.) and 1 in Nu- Mar (Steve Mlodinow). Four in Flor- cla, Montrose, 30 Apr – 1 May (Coen ence, Fremont, 5 Mar (Rich Miller). Dexter and Brenda Wright); rare in Two at Brush SWA, Morgan, 14 Mar western Colorado. (David Dowell). One at Two Buttes PURPLE FINCH: One female in SWA, Baca, 14 Mar (David Tønnes- Las Animas, Bent, occasionally from sen, Mark Peterson, Glenn Walbek). 9 Jan – 6 Mar (Duane Nelson). One As many as 5 at Chatfield SP Douglas( female northeast of Limon, Lincoln, 11 and Jefferson), 17 Mar – 8 Apr (Alec – 14 May (Glenn Walbek). Hopping, m.ob.). One near Hasty, Brown-capped Rosy-Finch: A Bent, 31 Mar (Irene Fortune). flock of 1,235 in Estes Park,Larimer , 9 Baltimore Oriole: One in Pla- May (Scott Rashid).

ACKNOWLEDGMENTS Contributions from the volunteer compilers are greatly appreciated: Jim Beatty (southwest), Coen Dexter (west), John Drummond (southeast), Forrest Luke (northwest), Brandon Percival, and David Silverman. Much of the information in this report was obtained from the eBird Basic Dataset from the Cornell Lab of Ornithology, Ithaca, New York.

David Dowell, [email protected]

220 Colorado Birds Fall 2015 Vol. 49 No. 4 CBRC REPORT

The 72nd Report of the Colorado Bird Records Committee

Mark Peterson, Chair Colorado Birds Records Committee, and Bill Maynard, volunteer

Introduction This 72nd report of the Colorado Bird Records Committee (hereafter CBRC or Committee) presents the results of deliberations of the CBRC involving 276 reports submitted by 112 observers and documenting of 95 species from the period May 1979 to April 2015. Per CBRC bylaws, all accepted records received a final 7-0 or 6-1 vote to accept. A backlog of accumulated records needs to be published before they become official, therefore only sightings of species representing first county records, taxa with very few Colorado records and reasons for a report not being accepted by the CBRC are detailed in this report. With this publication, Vaux’s Swift becomes Colorado’s 499th official bird species. All other records in this report are by necessity limited in details. Committee members voting on these reports were John Drum- mond (Colorado Springs) Doug Faulkner (Arvada) Peter Gent (Boulder) Tony Leukering (Largo, Florida) Bill Maynard (Colorado Springs) Dan Maynard (Denver) Mark Peterson (Colorado Springs) Bill Schmoker (Longmont) and Glenn Walbek (Castle Rock). The 71st report erroneously stated that the White Ibis (2013-182) observed in Alamosa, 28 July 2013, was a first for the San Luis Valley. It is not only the second for the San Luis Valley, but also the second for Alamosa. The first record is of one at Blanca Wetlands, 5 May 1998. We thank John Rawinski for bringing this error to our attention.

Committee News The CBRC continues to recruit excellent members from the local birding community. Mark Peterson is the new chairperson of the CBRC replacing Doug Faulkner, Colorado Field Ornithologists’ newest president. Mark has extensive birding experience throughout the state. He has been birding since five years of age―remembering singing Yellow-headed Black- birds (his current ringtone) and going to the Crane Festival at Monte Vista National Wildlife Refuge from his home in Waverly, Colorado. Mark is known as an excellent birder, the CFO County List Master, a past CFO board member and Convention Field Trip Coordinator.

Colorado Birds Fall 2015 Vol. 49 No. 4 221 Dan Maynard, replacing Mark Peterson on the CBRC, was born in Manitou Springs. He currently lives in Denver where he works on renewable energy projects as the Senior Ecologist for Core Con- sultants. When he isn’t speeding across Colorado in pursuit of a Big Year or Big Day, Dan can be found fly fishing, doing yoga or leading a technical rock climbing route on a pitch in Colorado or Utah.

Committee Functions The Committee solicits documentation of reports in Colorado for all species published in its Main Review List (coloradobirdrecords. org/ReviewList.aspx), species with no prior accepted record in Colo- rado and sightings of regularly occurring species that are considered out-of-range or out-of-season. Documentary materials should be submitted online at the CBRC website (coloradobirdrecords.org). Al- ternatively, one can fill out the form printed on the dust jacket of this journal and mail it to the CBRC Chair, or request an electronic document from the Chair or Secretary (see this journal’s inside front cover for contact information).

Report Format The records in this report are arranged taxonomically following the American Ornithologists’ Union (AOU) Check-list of North American Birds (AOU 1998) through the 56th Supplement (Chesser et al. 2015). We present the initials of the contributing observer(s), the official accession number and the vote tally in the first round and, if relevant, the second and third rounds (with the number of “accept” votes on the left side of the dash). The total number of state records is given in parentheses after the species scientific name. The initial observer of the bird is underlined, if known, and is presented first only if that person contributed documentation; additional contributors’ follow in alphabetical order by last name. If the initial observer is known with certainty, but did not submit documentation, those initials are underlined and presented last. Observers submitting a photograph or video capture are indicated with a dagger (†) and those who submitted a sketch by a lower-case, italicized “sk” (sk). In this report, county names are italicized. Abbreviations are used for the following: reservoir (Res.) state park (SP) and state wildlife area (SWA).

ACCEPTED RECORDS egon, and Texas have more. The new- With the publication of this re- est addition to the state list is Vaux’s port, Colorado’s state bird list stands Swift – Chaetura vauxi (2015-46; 7-0) at 499 species. Only Alaska, Arizona, with a well-photographed individual California, Florida, New Mexico, Or- reported by Brandon Percival west

222 Colorado Birds Fall 2015 Vol. 49 No. 4 eBird data showing migrant Vaux’s Swift wintering records from southeastern U.S. and from various locations in western New Mexico, Nevada, and Utah, in addition to western breeding areas. Image provided by eBird (www.ebird.org) 10 August 2015. of Cottonwood Picnic area along the (C. v. tamaulipensis). Small numbers Arkansas River, below Pueblo Reser- of North American breeders winter voir Dam, Pueblo on 28 April 2015. in the U.S. from central California The CBRC bylaws section VIII C south and also in southeastern Louisi- (10) states a first state record can be ana and in northwest Florida (Birds of established by a single observer docu- North America). mentation that includes photographic The Committee commented on or audio-recorded evidence supportive the quality of the photographs, date of the identification. In this case the of migration for this species compared CBRC accepts the photographic evi- with Chimney Swift (Chaetura pelagi- dence as supportive of the identifica- ca) and the details of the report sepa- tion, thereby establishing it as the first rating it from Chimneys. Experts from state record. outside Colorado were consulted, and Vaux’s Swift is named for William they too validated this report as a S. Vaux (1811–1882) a member of Vaux’s Swift. Tom Johnson’s thorough the Academy of Natural Sciences analysis of these two Chaetura swifts, of Philadelphia and it was described including a “modified aspect ratio” ap- by John K. Townsend in 1839 from proach and nine characters to look for specimens collected along the Colum- in separating these two species, occurs bia River. Vaux’s Swifts (C. v. vauxi) in the print version of the September/ breed in northwestern U.S., Canada, October 2013 Birding, pp. 48-52. and possibly in northeastern Mexico Brant – B. b. nigricans. (JTh†,

Colorado Birds Fall 2015 Vol. 49 No. 4 223 DD†, EL†, SGM; 2012-207; 7-0) Red-necked Grebe – Podiceps grise- Loveland area, Larimer, 3-18 Decem- gena (LF†, CH†; 2013-181; 7-0) Lake ber 2012; (SGM; 2013-13; 7-0) Jack- John, Jackson, 10-14 July 2013. son Lake, Morgan, 23 December 2012; Neotropic Cormorant – Phala- (NM†; 2013-16; 7-0) providing a first crocorax brasilianus (RHi†; 2013-112; for Otero found during the Rocky Ford 7-0) Valco Ponds SWA, Pueblo, 5 CBC at Lake Cheraw, 15 December April 2013; (SGM; 2013-130; 7-0) 2011; (RBe†; 2014-4; 7-0) Larimer, Stewarts Pond on WCR 46, Weld, 14 Prospect Ponds Natural Area, 31 De- April 2013; (SGM†; 2013-159; 7-0) cember 2013. Weld County Road 7 entry road to St Brant – Branta bernicla. The fol- Vrain State Park, Weld, 15 May 2013. lowing three documented Brant were Least Bittern – Ixobrychus exilis all unanimously accepted as Brant (RMi; 2012-203; 7-0) Holcim Wet- but not to any specific taxon. They lands, Fremont. 25 July 2012; (BKm; came from Redstone Park and Chat- 2013-165; 7-0) NE pond of Sawhill field State Park, Douglas, Greeley, Ponds complex, Boulder, 13 June 2013. Weld and Equalizer Lake and Houts Tricolored Heron – Egretta tricolor Reservoir, Larimer. (EDo†, JH†, BM†, (JD†, BKP†, SGM†, SM; 2013-167; CN†, KPe†, TR†, CW†, SS; 2013- 7-0) Holcim Wetlands, Fremont 14 290; 7-0) 15 December 2013 to 19 June 2013 to 3 July 2013; (JD†, BM†; February 2014; (SGM; SW; 2014-12; 2013-171; 7-0) Lake Hasty, Bent, 22 7-0) 15 January 2014; (SB†, SGM†; June 2013. 2014-20; 7-0) 25 October 2013 to 11 Reddish Egret – Egretta rufescens November 2013. (DD†, DN; 2013-265; 7-0) Lake Mer- Trumpeter Swan – Cygnus bucci- edith, Crowley, 13 July 2013; (JSt†; nator (BS†, NL; 2013-47; 6-1) McKay 2014-38; 7-0) John Martin Reservoir Lake, Adams, 13-19 January 2002. State Park, Bent; 20-22 August 2013. Eurasian Wigeon – Anas penelope Cattle Egret – Bubulcus ibis (BBa†; (RBr; 2012-197; 7-0) Colorado River, 2013-245; 7-0) Pagosa Springs, Archu- Mesa, 15 March 2010; (JD†, BKP†, leta, 1 November 2013. RMi†, DM; 2012-214; 7-0) Willow Yellow-crowned Night-Heron and Ash St. 16 and 23 December – Nyctanassa violacea (LH†; 2010- 2011 thru 1 January 2012 at Centen- 183; 6-1) Larimer, 5 September 2005; nial Park, Fremont; (SGM†; 2013- (HK†; 2013-110; 6-1) Chatfield State 256; 7-0) Weld, 20 March 2013; (JTr†; Park, Jefferson, 19 May 1979; (DD†, 2013-260; 7-0) Riverfront trail at 29 JD†, BM†, BP†, RT, KL; 2013-222; Road, Mesa, 27 April 2013; (HK†, 7-0) Birdsall Road, El Paso, 5-13 Oc- KPe†; 2014-41; 7-0) Walker Pit, tober 2013; (WG, BM†; 2014-24; Douglas, 15-16 March 2014. 7-0) Carp Lake, El Paso, 26-27 August Long-tailed Duck – Clangula hy- 2005. emalis (BKP†, SM; 2013-104; 7-0) Common Black Hawk – Buteogal- Brush Hollow Reservoir, Fremont, 20 lus anthracinus (JBs; 2013-249; 7-0) January 2012. Hotchkiss, Delta, 5 April 2013.

224 Colorado Birds Fall 2015 Vol. 49 No. 4 Black Rail – Laterallus jamaicensis Little Gull – Hydrocoloeus minutus (MP; 2013-229; 7-0) Holcim Wet- (NK†, SW; 2012-200; 7-0) Wind- lands, Fremont, 15 June 2013. sor Lake, Weld, 2 December 2012; Whimbrel – Numenius phaeopus (MO, CT; 2013-109; 7-0) Lake Mer- (MH; 2013-252; 7-0) Fruitgrowers edith, Crowley, 7 April 2013; (BM†, Reservoir, Delta, 20 May 2000. BKP†, RMo; 2013-220; 7-0) Pueblo Hudsonian Godwit – Limosa hae- Reservoir, Pueblo, 4-9 October 2013; mastica (DD†, GP; 2014-37; 7-0) Bee- (SGM, PG, NK†; 2013-243; 7-0) Ter- be Draw, Weld, 21-23 May 2013. ry Lake and Clark Reservoir, Boulder, Buff-breasted Sandpiper – Calid- 30 October thru 3 November 2013. ris subruficollis (DD†; 2014-18; 7-0) Mew Gull – Larus canus (TLe†, Jackson Reservoir, Morgan, 21 August LK; 2014-19; 7-0) Cherry Creek State 2013. Park, Arapahoe, 27 September 2008. American Woodcock – Scolopax Western Gull (4)– Larus occiden- minor (DG†; 2013-282; 7-0) specimen talis (SGM; 2013-239; 7-0) A well recovered at UCC Campus, El Paso, described but un-photographed adult 9 February 2013; (CT†, BM†, BKP†; dark-mantled gull found at Timnath 2014-21; 7-0) Fountain Creek, El Reservoir, Larimer, 5 October 2013 Paso, 9 February 2014; (KPa†; 2014- was compared with Herring, Lesser 31; 7-0) Fountain Creek Regional Black-backed and California Gulls. Park, El Paso, 15 January 2013. Committee members felt that all es- Red Phalarope – Phalaropus fuli- sential and secondary features were carius (CDe†; 2013-101; 7-0) Ridgway noted to separate congeners. Reservoir, Ouray, 20 August 2012. Iceland Gull – Larus glaucoides Pomarine Jaeger – Stercorarius po- (JVv, TLe; 2002-75; 7-0) Erie landfill marinus (EDe†, JD†, BM†; 2013-169; north of Hwy 7, Prince Lakes, Erie and 7-0) Antero Reservoir, Park, 11-17 Thomas Reservoirs, Boulder, 9-18 April June 2013; (GW†, KPe†; 2014-27; 2000; (DD†, NL, GW†; 2013-43; 7-0) 7-0) Chatfield State Park,Douglas and Teller Lake No. 5 and Culver Ponds, Jefferson, 16-26 October 2013; (DN†; Boulder, 1-2 February 2013; (BKP†; 2014-39; 7-0) Blue Lake (Adobe 2013-61; 7-0) Pueblo Reservoir, Pueb- Creek Reservoir) Kiowa, 18 June 2013. lo, 3 January 2013; (LMa†; 2013-93; Parasitic Jaeger – Stercorarius para- 6-1) Anthem Pond, Broomfield, 26 siticus (GK, GW†, DN; 2014-28; 7-0) January 2013; (SGM†; 2013-124; 6-1) Blue Lake (Adobe Creek Reservoir) Stewarts Pond, Weld, 31 March 2013; Bent and Kiowa, 4-9 November 2013. (SGM; 2013-126; 7-0) Black Hollow Black-legged Kittiwake – Rissa tri- Reservoir, Weld, 3 April 2013; (NK; dactyla (MH†; 2013-262; 7-0) High- 2014-5; 7-0) Lake Loveland, Larimer, line Lake State Park, Mesa, 19-20 No- 30 December thru 2 January 2014; vember 2013. (SGM†; 2014-36; 7-0) Woods Lake, Sabine’s Gull – Xema sabini (TLe†; Weld, 19 February 2014; (DD†, SGM; 2014-14; 7-0) Eleven Mile State Park, 2014-42; 7-0) Aurora Reservoir, Arap- Park, 29 October 2005. ahoe, 19-29 January 2014.

Colorado Birds Fall 2015 Vol. 49 No. 4 225 Slaty-backed Gull (2) – Larus The observer thought this bird, based schistisagus (DD†, SGM†, KPe†; on detailed photographic comparison, 2014-8; 7-0) Aurora Reservoir Arap- was the same gull reported from Pueb- ahoe hosted an adult Slaty-backed lo Reservoir, Pueblo on 29 December Gull 15 December 2013 through 3 2012. January 2014. Although the winter- Glaucous-winged Gull – Larus ing gull showed an un-streaked white glaucescens (SGM; 2013-35; 6-1) head, it also showed the characteristic Pueblo Reservoir, Pueblo, 1 January “string of pearls,” the bold pattern of 2013; (SGM, TLe; 2013-77; 7-0) Val- white mirrors and tongue tips seen on mont Reservoir, Boulder, 27 January the dorsal and ventral surfaces of the 2013; (DD†; 2013-264; 7-0) Neegron- outer primaries in flight, broad white da Reservoir, Kiowa, 10 August 2013; trailing edge to the secondaries (skirt) (SGM; 2013-267; 7-0) Windsor Res- dark slate-gray mantle, broad white ervoir, Weld, 13 November 2013; scapular and tertial crescents and (SGM; 2013-268; 7-0) Aurora Res- bright pink legs and feet, all charac- ervoir, Arapahoe, 24 November 2013; teristics of this very rare visitor from (SGM†; 2013-280; 7-0) Pueblo Res- Asia. Comparison with a look-alike ervoir, Pueblo, 11-12 December 2013; “Vega Gull”, was noted (longer wings, (SGM†; 2014-10; 7-0) Aurora Reser- thinner bill, lighter gray mantle, no- voir, Arapahoe, 3 January 2014; (BKP; ticeable contrast between black wing- 2014-29; 7-0) Pueblo Reservoir, Pueb- tips and upperparts) eliminating that lo, 15 February 2014. taxon. Distant, but distinct photo- Great Black-backed Gull – Larus graphs on different dates were key for marinus (CM†; 2013-108; 6-1) Cher- this second Colorado and first county ry Creek State Park, Arapahoe, 23 record. January 2011; (NK†; 2013-261; 7-0) Herring Gull x Glaucous-winged Horseshoe Lake, Larimer, 17 April Gull – (DD†; 2013-51; 7-0) Herring 2013. Gull (Larus argentatus) and Glaucous- Arctic Tern – Sterna paradisaea winged Gull (Larus glaucescens) regu- (GW†, DD; 2013-213; 7-0) Cherry larly interbreed in southwest Alaska Creek State Park, Arapahoe, 23 Sep- and their hybrids increasingly occur tember 2013; (SGM; 2013-217; 7-0) along the North American Pacific Terry Lake and Clark Reservoir, Boul- Coast south to California (Howell and der, 29 September 2013. Dunn. 2007). An apparent first year Inca Dove – Columbina inca hybrid was well photographed from (BKP†; 2006-190; 7-0) Rocky Ford, Teller Lake No. 5, Boulder, 24 Janu- Otero, 16 April 2005; (CA; 2013-37; ary 2014. The identification indica- 6-1) Cottonwood Canyon, Baca, 17 tors given in the report specify promi- May 2012; (JSt†; 2014-16; 7-0) Farm- nent wing patterning and patches of yard, Prowers, 14 October 2005. a lighter color on a mostly-black bill Black-billed Cuckoo – Coccyzus resembling a dark Glaucous-winged erythropthalmus (JBr†; 2013-209; 7-0) Gull or a washed out Herring Gull. this first forAdams County was found

226 Colorado Birds Fall 2015 Vol. 49 No. 4 at Barr Lake State Park, 14 September stay at an estate in Colorado Springs, 2013. 1 November 2013 thru 26 February Snowy Owl – Bubo scandiacus 2014. The estate’s caretakers, provid- (KMD, JK†; 2014-32; 7-0) HWY 94 ing the bird flowering plants along and LCR 11, Lincoln, 26 January 2014. with a protein supplement, were able Boreal Owl – Aegolius funereus to watch the male hummingbird molt (DJ, TM†; 2013-72; 7-0) southeast of its gorget feathers and by the end of Silverton, San Juan, 16 July 2009. the period the bird was frequently Lesser Nighthawk – Chordeiles seen in a territorial display (Colorado acutipennis (SGM; 2013-178; 7-0) Birds. Vol. 48. No. 3). Adobe Creek Reservoir, Kiowa, 22 Acorn Woodpecker – Melanerpes June 2013. formicivorus (MW†, PB†, JD†, NK†, Magnificent Hummingbird – Eu- TLe†, BM†, KMD†, NM†, SP; 2012- genes fulgens (MB; 2012-153; 7-0) for 211; 7-0) Willow Circle, El Paso, 15 the third year in a row this bird was December 2012 thru 18 April 2013; found at Tunnel Campground, Lar- (HK†, KD; 2013-244; 7-0) provid- imer, 16 July 2012. ing for a first forDouglas , this Acorn Ruby-throated Hummingbird – Woodpecker was found by Kathy and Archilochus colubris (SW†, NK†; 2012- Howard Dressel on 24 May 2013. 181; 7-0) Walters residence, south Red-bellied Woodpecker – Mel- Loveland, Larimer, 12-13 September anerpes carolinus (SGM†; 2011-198; 2012; (MM; 2013-139; 6-1) South 7-0) Crow Valley Campground, Weld, Mesa Trail, Boulder, 13 May 2013; 1 October 2011; (PWN†; 2014-3; (DS; 2013-202; 7-0) Colorado City 7-0) providing a first forHuerfano and Rye, Pueblo, 1 September 2013; county, Polly Wren Neldner found a (JSt†; 2013-225; 7-0) Farmyard, Prow- Red-bellied Woodpecker in her yard ers, 28-29 September 2013; (RHo†; which stay from 17 November 2004 2013-231; 7-0) Long Pond, Larimer, thru 10 February 2005. 18-21 September 2013; (LP†; 2014- Yellow-bellied Sapsucker – Sphy- 1; 7-0) a first forAlamosa county was rapicus varius (LA†; 2013-83; 7-0) found at the Medano-Zapata Ranch, Redlands area, Mesa, 6 February 2013. 13 September 2013; (MC†; 2014-30; Eastern Wood-Pewee – Contopus 7-0) Lakewood, Jefferson, 3-4 Octo- virens (SGM†; 2013-155; 7-0) Jules- ber 2013; (DD; 2014-34; 7-0) Lamar, burg, Sedgwick, 26 May 2013. Prowers, 2 October 2013. Yellow-bellied Flycatcher – Em- Anna’s Hummingbird – Calypte pidonax flaviventris (DLe†; 2013-251; anna (DS; 2013-201; 7-0) Colorado 6-1) overlooked or difficult to iden- City and Rye, Pueblo, 9 September tify, only the ninth Colorado record 2013; (RBr; 2013-281; 6-1) Grand and firstProwers county record was Junction, Mesa, 4-19 December 2004. recorded in Lamar on 15 September Costa’s Hummingbird – Calypte 2013. This small Empidonax flycatcher costae (BM†, BP†; 2013-273; 7-0) this breeds in coniferous forests and bogs first forEl Paso County had a long across Canada and into Alaska win-

Colorado Birds Fall 2015 Vol. 49 No. 4 227 tering from northeastern Mexico (BU†; 2012-201; 7-0) Rio Grande south to western Panama. Excellent State Wildlife Area, a first forRio photographic evidence supported the Grande, 19 July 2012; (DA†; 2013-75; bird having a complete eye ring, big 7-0) Florence River Walk, Fremont, head and a slightly larger version of a 15 June 2013; (BJ†; 2013-106; 7-0) La Least Flycatcher but with a longer pri- Veta, Huerfano, 9 September 2012. mary projection and blackish wings. Great Crested Flycatcher – Myiar- The one member voting not to ac- chus crinitus (SGM†; 2011-197; 7-0) cept the record thought the eye ring Thompson Ranch (private) Lincoln, 5 should be wider for this species and he September 2011. mentioned the primary project on the Brown-crested Flycatcher – My- well-photographed bird was too short iarchus tyrannulus (LP†; 2014-2; 7-0) for a Yellow-bellied Flycatcher. was found by visiting British birder, Alder Flycatcher – Empidonax Laurence Pitcher on the Medano-Za- alnorum (DF†; 2013-55; 7-0) Barr pata Ranch in the San Luis Valley Al- Lake SP, Adams, 1 September 2012; amosa on 29 June 2013. Only present (SGM†; 2013-189; 7-0) Last Chance, for one day, it will become only the Washington, 11 August 2013. second state and first county record. Least Flycatcher – Empidonax min- Photographs and a written description imus (PD; 2013-250; 7-0) Connected nicely separated it from its congeners, Lakes, Mesa, 26 May 2007. in particular Ash-throated (M. cinera- Hammond’s Flycatcher – Empi- scens) and Great Crested (M. crintus) donax hammondii (BM†, BKP†, DM; flycatchers. Experts living in Brown- 2013-34; 7-0) On the 113th Christ- crested’s U.S. range, southeastern mas Bird Count, in particular the California, extreme southern Utah annual Penrose CBC on 16 Decem- and Nevada, southeastern Arizona, ber 2012, Dan Maynard detected an southwestern New Mexico, and south Empidonax flycatcher where a spring Texas were consulted. This southern begins its descent into a wooded ra- species is a resident in parts of Mexico, vine on a Willow Street dairy farm Central America, and in South Amer- in Cañon City, Fremont county. The ica. In South America it breeds mostly bird was seen by many, photographed, east of the Andes south to southern and documented. It remained for six Brazil, Paraguay, and northern Argen- days, becoming the firstEmpidonax fly- tina (Cardiff and Dittmann, 2000). catcher documented in December in Eastern Kingbird – Tyrannus tyran- Colorado. nus (JD; 2013-170; 7-0) Antero Reser- Gray Flycatcher – Empidonax voir, Park, 17 June 2013. wrightii (SGM†; 2011-195; 7-0) Crow Scissor-tailed Flycatcher – Tyran- Valley Campground, Weld, 20 Au- nus forficatus (DB; 2013-26; 7-0) just gust 2011; (SGM†; 2011-196; 7-0) east of the Cottonwood Canyon pic- Thompson Ranch, Lincoln, 5 Septem- nic area and campground, Las Animas, ber 2011. 1 June 1996. Black Phoebe – Sayornis nigricans Pacific Wren – Troglodytes pacificus

228 Colorado Birds Fall 2015 Vol. 49 No. 4 (GW; 2014-26; 7-0) this provides a Golden-winged Warbler – Vermi- first county record that was found at vora chrysoptera (TLe; 2013-278; 6-1) the private Thompson Ranch, Lincoln Barr Lake State Park, Adams, County. Prothonotary Warbler – Proto- Winter Wren – Troglodytes hiemalis notaria citrea (TM†; 2012-187; 7-0) (KMD; 2012-79; 7-0) trail to Black found by Robin and Kendall Henry Lake in Rocky Mountain National in Glenwood Springs on 9 September Park (Glacier Gorge Trailhead) Lar- 2012, was a first for Garfield county; imer, a rare summer record from 2 July (SA; 2013-214; 7-0) Pastorius State 2012; (CL†; 2013-19; 7-0) Durango, Wildlife Area, La Plata, 9 September La Plata, 24 December 2012. 2013. Sedge Wren – Cistothorus platensis Tennessee Warbler – Oreothlypis (SGM; 2012-191; 7-0) Kinny SWA, peregrina (BP†; 2013-271; 7-0) Pueblo Lincoln, 21 October 2012; (NM†; City Park, Pueblo, this bird found in 2013-14; 7-0) Walden Ponds, Boulder, November stayed until at least 1 De- 17 November 2011; (SGM; 2013-240; cember 2013 to provide a first winter 7-0) TNC Fox Ranch (private) Yuma, record for Colorado. 12 October 2013; (BBi†; 2013-241; Connecticut Warbler – Oporor- 7-0) Spring Creek Trail, Larimer, 24 nis agilis (NG†; 2013-29; 7-0) Chico October 2013; (DD†; 2014-15; 7-0) Basin Ranch, El Paso, 10 September Prewitt Reservoir, Logan, 16 Novem- 2012; (SGM, GW; 2013-195; 7-0) ber 2013. Prewitt Reservoir State Wildlife Area, Gray-cheeked Thrush – Catharus Washington, 2 September 2013. minimus (NG†; 2014-17; 7-0) Chico Mourning Warbler – Geothlypis Basin Ranch, El Paso, 13 May 2013; Philadelphia (BKP†; 2013-145; 7-0) (NG†; 2014-22; 7-0) Chico Basin Brett Gray Ranch (private) Lincoln, Ranch, El Paso, 10 May 2013; (NG†; 18 May 2013; (SGM; 2013-204; 7-0) 2014-23; 7-0) Chico Basin Ranch, El Flagler Reservoir State Wildlife Area, Paso, 16 May 2013. Kit Carson, 11 September 2013; (NK†, Varied Thrush – Ixoreus naevius KK, JSh; 2013-207; 7-0) Fort Col- (BKP; 2013-117; 7-0) Walsenburg, lins, Larimer, 9-10 September 2013; providing a first forHuerfano , 1 April (MM; 2013-208; 7-0) Walden Ponds/ 2000; (BKP†, PWN†; 2014-11; 7-0) Sawhill Ponds Complex, Boulder, 11 La Veta, Huerfano, 12-30 January September 2013; (SGM†; 2013-212; 2014. 7-0) Jackson Reservoir, Morgan, 2 McCown’s Longspur – Rhyncho- September 2013. phanes mccownii (TLi, CDo; 2013- Kentucky Warbler – Geothlypis 118; 7-0) 4 miles west of Steamboat formosa (TLe†; 2012-196; 7-0) Pritch- Springs, Routt, 18-19 April 2013. ett, Baca, 31 May 2011. Worm-eating Warbler – Helmithe- Cape May Warbler – Setophaga ros vermivorum (CDe†; 2014-7; 7-0) tigrina (AS†; 2012-186; 7-0) Kiowa Grand Junction, Mesa, 28-29 Novem- Creek Sanctuary, El Paso, 2 October ber 2013. 2012; (BKP†, RO†, GW†; 2013-138;

Colorado Birds Fall 2015 Vol. 49 No. 4 229 7-0) Two Buttes State Wildlife Area, ber 2011; (BKP; 2013-224; 7-0) Pueb- Baca, 10-11 May 2013; (BKP†; 2013- lo Reservoir area, Pueblo, 7 September 149; 7-0) Chico Basin Ranch, Pueblo, 2013; (DLe†; 2013-253; 7-0) Lamar, 22 May 2013; (BKP†, JD†, SGM†; Prowers, 16 September 2013. 2013-152; 7-0) Chico Basin Ranch, Eastern Towhee – Pipilo eryth- Pueblo, 22-24 May 2013; (GW†; rophthalmus (SGM; 2012-198; 6-1) 2013-196; 7-0) South Republican Tamarack Ranch SWA, Logan, 2 June SWA, Yuma, 21 May 2013; (DLe†; 2011; (DD†; 2012-216; 6-1) Tama- 2013-257; 7-0) Grandview Cemetery, rack Ranch SWA, Logan, 7 July 2012; Larimer, 7-8 October 2013. (BKP†; 2013-2; 7-0) Greenwood, Northern Parula – Setophaga amer- Custer, 1 January 2013, although not icana (BKP†; 2013-74; 7-0) Pueblo documented this bird was seen into City Park, Pueblo, 5 December 2012. April of 2013; (SGM; 2013-154; 7-0) Bay-breasted Warbler – Setophaga Tamarack Ranch SWA, Logan, 26 castanea (DLe†; 2013-258; 7-0) Boul- May 2013; (RR; 2013-283; 6-1) east der, Boulder, this bird was around for of I76 on 160th just east of the railroad approximately three weeks but only tracks, Adams, 4-31 January 2013. documented for 9 November 2013. Field Sparrow – Spizella pusilla Blackburnian Warbler – Setophaga (SGM; 2011-194; 7-0) Black Hollow fusca (HK; 2013-276; 7-0) Chatfield Reservoir, Weld, 5 May 2001; (JD; State Park, Jefferson, 7 October 1987. 2013-30; 7-0) Chico Basin Ranch, El Chestnut-sided Warbler – Setoph- Paso, 5 October 2012; (BKP; 2013- aga pensylvanica (JBe†; 2012-180; 7-0) 223; 7-0) Chico Basin Ranch, Pueblo, Navajo Reservoir, Archuleta, 2 Octo- 28 September 2013. ber 2012. White-throated Sparrow – Zono- Yellow-throated Warbler – Setoph- trichia albicollis (TLe†, SGM; 2013-50; aga dominica (BKP†; 2013-73; 7-0) 7-0) Moose Visitor Center, Jackson, 26 Pueblo City Park, Pueblo, this long January 2013. A nice high elevation staying bird showed up in Septem- record for this species in Colorado. ber and was last seen on 8 December There was also one at this location the 2012. previous year but not documented. Prairie Warbler – Setophaga dis- Hepatic Tanager – Piranga flava color (BKP, MP; 2013-114; 7-0) Lake (SO; 2013-254; 7-0) 5 miles south of DeWeese, Custer, 21 September 2004; Tobe, Las Animas, 14 May 2004. (BKP, DS; 2013-115; 7-0) Diversion Scarlet Tanager – Piranga olivacea Gate near Colorado City, Pueblo, 8 (SW; 2012-193; 7-0) Loveland, Lar- May 2003. imer, 9 September 2012; (DE; 2013- Hermit Warbler – Setophaga occi- 263; 6-1) McKay Lake, Adams, 5 May dentalis (BKP; 2013-113; 7-0) Upper 2005; (RS; 2013-277; 7-0) Chautau- Queens Reservoir, Kiowa, 6 May 2001. qua Cabins, Boulder, 18 February 1994. Canada Warbler – Cardellina ca- Eastern Meadowlark – Sturnella nadensis (DR; 2013-95; 6-1) Lamar magna (BKm; 2013-164; 6-1) Beech Community College, Prowers, 7 Octo- Open Space, Boulder, 13 June 2013.

230 Colorado Birds Fall 2015 Vol. 49 No. 4 Baltimore Oriole – Icterus galbula posture or include a sound recording (TM; 2014-33; 7-0) providing a first or a sonogram when possible. for Garfield County, this Baltimore Mute Swan – Cygnus olor. In spite Oriole was found by Robin and Ken- of almost yearly sightings of Mute dall Henry in Glenwood Springs on Swan in Colorado, there have been no 15-16 May 2013. records of the species accepted and it Purple Finch – Haemorhous purpu- currently does not appear on the Col- reus (SGM; 2012-188; 6-1) Holyoke, orado Bird Checklist. There is no cur- Phillips, 30 September 2012; (GW†; rently accepted method to determine 2013-96; 7-0) Castle Rock, Douglas, if Colorado Mute Swans escaped from 25 December 2012 thru 15 March captivity or if they wandered to Colo- 2013; (MP†; 2013-232; 7-0) Flagler rado on their own. For example, what Reservoir State Wildlife Area, Kit is the provenance of the Mute Swan Carson, 13 October 2013. west of Boulder Creek in Weld on 27 October 2013? The reported bird was RECORDS NOT ACCEPTED an obvious Mute Swan, but one of un- Every Colorado birder, beginner known origin (2013-238; 3-4). and expert alike, will sooner or later Trumpeter Swan – Cygnus buccina- have a bird report “not accepted” by tors. Lack of a detailed description or the CBRC. While some written de- photographs separating this from the scriptions may describe a look-alike smaller Tundra Swan (Cygnus colum- species or subspecies causing the bianus) persuaded a majority of CBRC non-acceptance, more often than members to not accept this 15 No- not, unaccepted reports simply do not vember 2012 report (2012-185; 3-4) provide enough descriptive details or from North Delaney Lake, Jackson. convincing photographs to provide Glossy Ibis – Plegadis falcinellus. A “without a doubt” evidence to support Plegadis ibis seen on 18 April 2004 at a record. Or, the key call or song was 20 Mile Road, Routt was not accept- not heard well or not described well ed by Committee members primarily or at all. Even a 5-2 majority vote in because the bird was not in full alter- favor of a record being accepted does nate plumage and four of the mem- not meet the required 6-1 or 7-0. The bers commented that the report did bird may, in fact refer to the species not rule out a hybrid (2013-248; 3-4). reported, but the details provided may Hybrid White-faced Ibis x Glossy Ibis, have been not convincing enough. depicted and described as “intermedi- Do not be insulted. Next time, detail ate” by Sibley (2014) are increasingly every key identification point you ob- reported from Colorado (see Leuker- served (but not a word-for-word field ing 2008). One reviewer mentioned guide description). Separate all of the that size is not a consistent character look-alike species and when appropri- for separating the two species. ate address potential hybrids. When Swallow-tailed Kite – Elanoides photographing, attempt to get clear forficatus. An observer driving north shots that show key features/behavior/ on I-25 in Larimer on 3 April 2013

Colorado Birds Fall 2015 Vol. 49 No. 4 231 was unable to present convincing ers, reports to records committees of details of the raptor he thought was Harris’s Hawks require extra scrutiny this species. The driving speed, 75 and observers should look for bands mph, was felt as giving the observer and/or jesses and should state such in too little time to sufficiently identify their submitted details. This aspect such a rarity; Colorado has only five was noted by many reviewers for both accepted records (2013-99; 0-7) the of these reports. last in 1993. Western Gull – Larus occidenta- Harris’s Hawk – Parabuteo unicinc- lis. A dark-mantled gull fitting the tus. A dark raptor was described from description of Western Gull was re- near Holly Municipal Airport, Prow- ported from Totten Reservoir, Mont- ers on 22 April 2012. Three rounds ezuma on 22 April 2012. During the of voting did not provide the margin second round of voting (2012-64; 5-2; needed for acceptance. Negative vote 2-5) Committee members decided a comments suggested a reported band hybrid could not be completely ruled on the tail was not visible in the sub- out based on a series of photographs mitted photographs (2013-65; 4-3; showing mantle coloration a bit light- 4-3; 5-2). One review agreed with the er than expected and with leg and feet I.D. but was not okay with the bird’s color not perfectly matching either provenance, due to the extensive use of the two Pacific Coast subspecies of of Harris’s Hawks by falconers (pos- Western Gull. sible escaped bird). One reviewer Herring (Vega) Gull – Larus ar- suggested the reported raptor might gentatus vegae. Though still considered be a dark-morph Ferruginous Hawk a subspecies of Herring Gull by the whereas another reviewer, one who AOU Check-list Committee (Chess- voted in favor of acceptance, men- er et al. 2015) the eastern Siberian tioned Harris’s Hawk was the only form known as Vega Gull is regular in Colorado raptor showing the chestnut western Alaska, but with only a few shoulder patches seen in the submit- accepted records from farther south ted photographs. Also mentioned as a on the U. S. coast. Adults are slightly plus in favor or acceptance were vis- darker-mantled in adult plumages ible tarsi feathered halfway, a good than is the typical ABA-area form character for Harris’s Hawk. Another (smithsonianus) and have brighter reviewer liked the amount of yellow pink legs and dark eyes. A gull at Lake on the bird’s cere for Harris’s Hawk. Loveland, Larimer on 28 December A raptor seen on 10 October 2013 at 2011 was thought by CBRC members Crown Hill Park/Lake/Cemetery, Jef- to be inseparable from the highly vari- ferson was observed without binocu- able plumage of Herring Gulls win- lars (2013-230; 0-7). All Committee tering in Colorado (2012-209; 1-6). members mentioned a lack of details Another individual was reported from in the report and questioned whether Lake Loveland, Larimer on 17 Decem- the bird’s identification. Due to the ber 2012. The bird exhibited large popularity of the species with falcon- scapular and tertial crescents and ex-

232 Colorado Birds Fall 2015 Vol. 49 No. 4 tensive neck streaking, but the report other hummingbird species except was not accepted by the Committee Black-chinned (2013-233; 4-3; 0-7). because photographs were thought to Neither the photographs nor a de- be inconclusive (2012-210; 0-7). tailed description could eliminate Ruby-throated Hummingbird – Black-chinned Hummingbird for a Archilocus colubris. Only two species of majority of Committee members con- Archilochus hummingbird exist in the cerning a report from Spring Creek world. With a good view and/or upon Trail, Larimer on 21 September 2013 examination of photographs show- (2013-274; 3-4). ing a profile view of the folded wings, Yellow-bellied Sapsucker – Sphy- identification to genus is straightfor- rapicus varius. A 19 February 2005 ward, with the noticeable difference sapsucker report from Pueblo City in width between the narrow inner Park, Pueblo required two rounds of primaries and the broad outer pri- voting (2005-13; 5-2; 3-4) for a deci- maries being definitive. Separating sion to be reached. Two voters men- Ruby-throated from Black-chinned tioned that the lack of a red nape does Hummingbird (A. alexandri) however, not necessarily eliminate Red-naped is more difficult, and the shape of the Sapsucker. Observers should focus on tip of the outermost primary is an im- more than just the presence or absence portant separator, particularly in fe- of a red nape patch, particularly the males and many immature males. The back pattern and the precise details committee here provides details on of red, black, and white on the throat. four reports that were found at least Additionally, some members noted somewhat lacking. The Committee that Yellow-bellied x Red-naped Sap- commented that the presented evi- sucker, a regular hybrid combination, dence for a hummingbird in southern was not addressed. Prowers on 5 September 2013 was in- Coastal Pacific Group Downy sufficient to eliminate Black-chinned Woodpecker – Picoides pubescens Hummingbird (2013-187; 5-2, 1-6). gairdnerii. Spots on the upper breast, The primary tips were not described not streaks was indicative of a Downy sufficiently, although most Committee Woodpecker seen at Ish Reservoir, members believed the report pointed Boulder on 20 October 2012, but toward Ruby-throated Humming- some members felt intergrades with bird. Committee members expressed Rocky Mountain subspecies of Downy concern about insufficient details in Woodpecker could not be ruled out. the report one noted 25 July 2013 at Other voters wanted more informa- Lakewood, Jefferson. (2013-194; 3-4) tion on patterns of vagrancy in Pacific and four voters thought the lack of a Downies before adding this north- “wing whirr” did not sufficiently rule western subspecies group to the offi- out Black-chinned Hummingbird. cial Colorado list (2012-190; 3-4). Details of another, reported from Es- Eastern Wood-Pewee – Contopus tes Park, Larimer on 29 August 2013, virens. An old record from 27 May were sufficient to differentiate it from 2009 was evaluated. Photographs of a

Colorado Birds Fall 2015 Vol. 49 No. 4 233 silent wood-pewee in Pueblo were not report had some conflicting details enough to convince two Committee about the belly color and the length members to accept this report after of the tail streamers, enough to leave three rounds of voting (2009-120; some doubt in the mind of four Com- 5-2; 5-2; 5-2). Eastern Wood-Pewee mittee members (2013-98; 3-4). usually has less dark tip on its orange Chihuahuan Raven – Corvus cryp- bill than Western, more of a greenish toleucus. Perhaps the most difficult cast to upperparts or breast, and the field-identification problem in Colo- greater coverts are usually broader, but rado is separating Chihuahuan Raven these are all subtle secondary charac- from Common Raven (C. corax). An ters with some overlap found in mu- out-of-range bird at Longmont, Boul- seum specimens. Reviewers were re- der, on 13 December 2012 was unani- luctant to accept a report of another mously thought to be insufficiently silent wood-pewee, from Lake Beck- separated from the more expected with Dam, Pueblo on 27 May 2013 Common Raven (2012-205; 0-7). The (2013-153; 2-5). Some comments description was of just the call notes. mentioned that the observer did not Another report originated from the see enough of the bird’s plumage and Big Thompson River Walk, Larimer, that the observation was of short du- on 20 April 2013. Some reviewers ration. See Lee et al. (2008) for a very commented on the lack of details in good article dealing with the separa- the description of the raven’s tail, the tion of wood-pewee species. lack of a detailed analysis of the call Alder Flycatcher – Empidonax notes, and the northern Colorado lo- alnorum. A 22 July 2012 Empidonax cation of this southern species. Others flycatcher from Kinney SWALincoln commented on the general difficulty did not receive the necessary votes by of differentiating the two Colorado ra- the Committee for acceptance. The ven species. Pieplow (2014) discusses “no” vote comments (2012-87; 4-3; raven vocalizations, while Leukering 3-4) mention the early date for this (2015a) discusses visual identification normally late migrant and the diffi- elsewhere in this issue. culty in positively separating Alders Pacific Wren – Troglodytes pacifi- from the eastern subspecies of Willow cus. The subspecies of Pacific Wren Flycatcher (Empidonax trailii trailii) in most likely to occur in Colorado, T. some circumstances. Another Com- p. salebrosus, is not generally depicted mittee member thought hearing only well in field guides and, in many re- one note was insufficient for conclu- spects, is quite similar in appearance sive evidence supporting the reported to Winter Wren (Leukering 2010) identification. thus it causes confusion here. The re- Scissor-tailed Flycatcher – Tyran- port of a dark, stub-tailed wren from nus forficatus. The Road 18 overlook Fox Ranch, Yuma, on 6 October 2012 at John Martin Reservoir, Bent was the was not accepted, mostly because spot where a Scissor-tailed Flycatcher the report lacked a good photograph was reported on 29 July 2012. The and, apparently, no sound recording

234 Colorado Birds Fall 2015 Vol. 49 No. 4 was made, though double-noted calls than Swainson’s Thrush (Leukering were described as being similar to a 2007, 2015b). Wilson’s Warbler’s call (2012-136; Swainson’s (Russet-backed group) 4-3; 3-4). See Leukering (2010) and Thrush – Catharus usutulatus. Swain- Faulkner (2012) for more discussion son’s Thrush subspecies breeding on on differences and references. the Pacific slope, known as Russet- Winter Wren – Troglodytes hiemelis. backed Thrush, have been recorded as On 19 May 2013, a likely stub-tailed spring migrants in Colorado (Mlodi- wren was heard “chipping” from the now et al. 2013 and references there- south end of Old Lime Road, San in). They differ from the form that Juan. Reviewers mentioned that the breeds in Colorado (C. u. swainsoni) observer did not have a binocular at Olive-backed Thrush, by their rus- the time of the sighting and did not set back coloration and dark flanks provide details of how its congener, (among other features) often looking Pacific Wren T( . pacificus) was ruled similar to Veery (C. fuscescens). Some out (2013-150; 3-4). A stub-tailed Committee members thought that the wren was seen, but not heard, on 15 photograph of a thrush from Chico Ba- November 2002 in Hotchkiss, Delta. sin Ranch, El Paso, on 15 September This sighting occurred before the 2013 (2013-226; 3-4) did not show split of Winter Wren into three spe- enough russet tones on its back to be cies (Chesser et al. 2010) and few properly considered referable to the were aware of the differences between Russet-backed Thrush group. the two ABA-area taxa in call notes, Bendire’s Thrasher – Toxostoma dorsal spotting, and coloration when bendirei. The difficulty of differentiat- the report was submitted. Much new ing the very-rare-in-Colorado Ben- information has been presented since dire’s Thrasher from juvenile Curve- 2002 on the topic of differentiating billed Thrasher (T. curvirostre) and Pacific and Winter Wrens, so it is not worn adult Sage Thrasher (Oreoscop- surprising that the Committee did not tes montanus) remains a stumbling accept this report (2013-246; 1-6). block for the Committee. This report Gray-cheeked Thrush – Catha- was of a single Bendire’s from north of rus minimus. The report of a Catharus Del Norte, Saguache, on 20 June 2000 thrush at Crow Valley Campground, (2012-212; 1-6). Although Curve- Weld, on 24 May 2012 fell one vote billed Thrasher is very rare, at best, in short of being accepted (2012-75; the San Luis Valley, Sage Thrasher is 5-2; 5-2; 5-2). After each of the three a common local breeder. rounds of voting, the two “no” votes Smith’s Longspur – Calcarius pictus. mentioned the thrush’s cheek color One was reported from Cherry Creek had not been described as cold gray State Park, Arapahoe, on 30 April 2013 a key field mark ofC. minimus. Un- (2013-133; 1-6). Reviewers’ comments like in the East, the primary confu- indicate that this report was not ac- sion species for Gray-cheeked Thrush cepted mostly for a lack of photograph- in Colorado is Hermit Thrush rather ic evidence and the scanty description.

Colorado Birds Fall 2015 Vol. 49 No. 4 235 Louisiana Waterthrush – Parkesia Lamar Community College Woods, motacilla. A 7 September 2011 water- Prowers, was the location described as thrush was described from below the harboring a wintering towhee, 7 Janu- dam at Two Buttes Reservoir SWA, ary 2013 (2013-36; 4-3; 2-5). As more Baca (2013-3; 2-5). Reviewers com- photographic documentation was mented on the late date for this spe- submitted before the second round of cies and that the throat streaking was voting, some reviewers commented on not described, which would help dif- visible white spotting on the tertials ferentiate it from the more common and on wing coverts suggesting a hy- congener, Northern Waterthrush (P. brid Eastern x Spotted Towhee. noveboracensis). LeConte’s Sparrow – Ammodramus Bay-breasted Warbler – Setophaga leconteii. Four Committee members castanea. A report came from 22 Sep- thought the description of this sparrow tember 1992 of a Bay-breasted War- from below the John Martin Reser- bler at what was then, and still is, a voir bunkhouse, Bent, on 4 April 2013 migrant trap, Last Chance, Washing- (2013-97; 3-4) did not rule out the oth- ton, (2013-275; 5-2; 4-3). Reviewers er similar Ammodramus sparrows, espe- commented on the elapsed time (23 cially Nelson’s Sparrow (A. nelsoni). years) between the sighting and the Common Redpoll – Acanthis flam- report submission and that the expe- mea. Now that Hoary Redpoll (Acan- rienced observer did not separate this this hornemanni) has been documented species from two look-alike species, as occurring in Colorado, Commit- Pine Warbler (S. pinus) and Blackpoll tee members voiced concern about Warbler (S. striata). Hoary Redpoll not being eliminated Eastern Towhee – Pipilo erythroph- in the report, especially evident after thalmus. One was reported from Cot- the second round of voting (2013-42; tonwood Canyon, Baca, on 12 May 5-2; 2-5). The bird was described from 2012 (2012-60; 5-2; 3-4). This audio- South Fork, Rio Grande, on 2 January only report was felt by the Commit- 2013. Another, reported on 2 April tee to require plumage details, as the 2013 from near Clark, Routt (2013-94; species, like most passerines, learns its 1-6) was believed by the Committee song, so the bird may have been a hy- to be a redpoll, but their concern was brid (which are depressingly regular in with the scanty and vague details in Colorado) or a confused Spotted To- the description not eliminating other whee. The well-known migrant trap, look-alike species.

REPORTERS AND CITED OBSERVERS The CBRC thanks the following individuals for submitting records of or discovering and reporting the rare species in Colorado discussed in this report: Dale Adams, Chuck Aid, Susan Allerton, Larry Arnold, Ben Bailey, Jason Beason, James Beatty, Robert Beau- champ, Dan Belter, Brad Biggerstaff, JD Birchmeier, Maggie Boswell, Robert Bradley, John Breitsch, Peter Burke, Frank Cada, Mark Chavez, Eric DeFonso, Peter Derven, Coen Dexter, Scott Dieni, Craig Dodson, Edward Donnan, David Dowell, John Drum- mond, Kathy Mihm Dunning, David Ely, Lee Farrell, Doug Faulkner, Peter Gent, Brian

236 Colorado Birds Fall 2015 Vol. 49 No. 4 Gibbons, Nancy Gobris, Doug Gould, Laurens Halsey, Judith Henderson, Mike Henwood, Robb Hinds, Rachel Hopper, Charles Hundertmark, Bev- erly Jensen, David Johnson, Bonnie Kaake, Bill Kaempfer, Kevin Keirn, Joey Kellner, Amy Kenyon, Loch Kilpatrick, Michael King, Hugh Kingery, Gary Koehn, Nicholas Komar, Kaye Lafreniere, David Laliberte, David Leather- man, Tony Leukering, Norm Lewis, Thomas Litteral, Carl Lundblad, Eric Lutomski, Cynthia Madsen, Luis Matheus, Bill Maynard, Tom McConnell, Rich Miller, Mark Minner-Lee, Steven G Mlodinow, Larry Modesitt, Nick Moore, Andrew Morris, Riley Morris, SeEtta Moss, Polly Wren Neldner, Duane Nelson, James Nelson, Andrea Niess, Charlie Nims, Michael Obrien, Ric Olson, Steve Olson, Ken Pals, Scott Pendleton, Brandon K. Percival, Guillaume Peron, Kris Petersen, Mark Peterson, Laurence Pitcher, Greg Prelich, Rob Raker, Andrea Robinsong, Dorothy Russell, Tim Ryan, Bill Schmoker, Cathy Sheeter, John Shenot, Aaron Shipe, Randy Siebert, David Silverman, Steve Stachowiak, Jane Stulp, Richard Taylor, Cheryl Teuton, Jim Thompson, Jackson Trappett, Van Truan, Brian Underwood, John Van- derpoel, Glenn Walbek, Sean Walters, Christopher Warneke, Marty Wolf, Jimmy Woodard, Randi Young.

LITERATURE CITED American Ornithologists’ Union. 1998. Checklist of North American Birds. Lawrence, KS: Allen Press. American Ornithologists’ Union (AOU). 1998. Check-list of North Ameri- can Birds. Lawrence, KS: Allen Press. Howell, N.G., and J. Dunn. 2007. A Reference Guide to Gulls of the Ameri- cas. Houghton Mifflin Company. Boston New York. pp. 482-483. Bull, E. L. and C. T. Collins. 2007. Vaux’s Swift (Chaetura vauxi) The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithol- ogy; Retrieved from the Birds of North America Online: http://bna.birds. cornell.edu/bna/species/077. Chesser, T. R., Banks, R. C., Barker, F. K., Cicero, C., Dunn, J. L., Kratter, A. W., Lovette, I. J., Rasmussen, P. C., Remsen, Jr., J. V., Rising, J. D., Stotz, D. F., and K. Winker. 2010. Fifty-first Supplement to the American Ornithologists’ Union check-list of North American Birds. Auk 127 (3): 726-744. Chesser, T. R., Banks, R. C., Burns, K. J., Cicero, C., Dunn, J. L., Kratter, A. W., Lovette, I. J., Navarro-Siguenza, A. G., Rasmussen, P. C., Rem- sen, Jr., J. V., Rising, J. D., Stotz, D. F., and K. Winker. 2015. Fifty-sixth Supplement to the American Ornithologists’ Union Check-list of North American Birds. Auk 132(3): CSi-CSxvi. Maynard, B. 2014. A Costa’s Hummingbird (Calypte costae) in Colorado Springs. Colorado Birds 48:199-203. Cardiff, Steven W. and Donna L. Dittmann. 2000. Brown-crested Fly- catcher (Myiarchus tyrannulus) The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/ species/496doi:10.2173/bna.496.

Colorado Birds Fall 2015 Vol. 49 No. 4 237 eBird. 2012. eBird: An online database of bird distribution and abundance. eBird, Ithaca, New York. Available: http://www.ebird.org. [Accessed: Au- gust 10, 2015.] Howell, S. N. G., and J. Dunn. 2007. Gulls of the Americas. Houghton Mif- flin, Boston. Johnson, T. 2013. Answers to July Photo Quiz. Birding 45(5):48-52. Faulkner, D. 2012. The 63rd Report of the Colorado Bird Records Commit- tee. Colorado Birds 46:188-197. Lee, C-T., Birch, A., and T.E. Eubanks. 2008. Field identification of Western and Eastern Wood-Pewees. Birding 40(5):34-40. www.aba.org/birding/ v40n5p34.pdf Leukering, T. 2007. Gray-cheeked Thrush. Colorado Birds 41:59-62. Leukering, T. 2008. Glossy Ibis and the identification challenges of hybrid Plegadis in Colorado. Colorado Birds 42:147-149. Leukering, T., and N. Pieplow. 2010. Pacific and Winter Wrens. Colorado Birds 44:281-286. Leukering, T. 2015a. Ravens in Colorado: An impossible field identification? Colorado Birds 49:255-262. Leukering, T. 2015b. The unfamiliar familiar Hermit Thrush. Birding 47(4):54-56. McNair, D. B. and T. E. Lewis. Vaux’s Swifts overwinter at a roost in Apala- chicola, Florida. 1997. Fla. Field Nat. 25(2):54-57. Mlodinow, S. G., T. Leukering, and N. Pieplow. 2013. “Russet-backed” Swainson’s Thrush. Colorado Birds 47:135-142. Pieplow, N. 2014. Common vs. Chihuahuan Ravens. Earbirding.com (http:// earbirding.com/blog/archives/4736). [Accessed 4 August 2015] Sibley, D. A. The Sibley Guide to Birds, Second Edition. 2014 Alfred A. Knopf, New York.

Mark Peterson, [email protected] Bill Maynard, [email protected]

238 Colorado Birds Fall 2015 Vol. 49 No. 4 Computer Modeling to Improve Flock-size Estimates

Alyssa H. Rawinski Monte Vista Middle School Science Fair Project 2015

Abstract The National Audubon Society predicts 314 species of birds are inching closer to extinction because of climate change. It will be very important for biologists and bird watchers to estimate bird numbers accurately as bird populations are monitored. I chose to test traits, skills and characteristics that may affect bird counting accuracy. I used the Jack Hodges computer model/simulation Wildlife Counts to determine whether training improved estimating accuracy. I randomly selected biologists and bird watchers from a local list. Each participant was shown screens with an unknown number of birds, and was asked to estimate the flock size. In general participants made significant improvements after being trained using Wildlife Counts. Comparisons of groups (i.e. biologist vs. bird watcher, male vs. female, caffeine vs. no caffeine, artist vs. scientist) yielded no significant differences. Within each group, all members demonstrated a significant improvement in estimating flock size after training. I also used real bird photos and found there were significant differences between simulation and real bird photo estimates. This seems to indicate that there are other factors that may affect counting accuracy. One report said people tend to underestimate numbers in large flocks. My findings agree with that statement, even after training. In conclusion, there were no specific characteristics that affected the accuracy of flock size estimates, meaning that all individuals, regardless of background and traits, can count birds and improve through prac- tice with the simulation. Training study participants using the Wildlife Counts program significantly improved their estimates of flock size. Similar training for anyone who monitors bird populations is recommended.

Introduction According to the National Audubon Society (NAS), bird populations may be facing serious threats and declines due to global warming and climate change (Nijhuis, 2014). It will become very important for biologists and bird watchers to estimate bird numbers accurately.

Colorado Birds Fall 2015 Vol. 49 No. 4 239 When I read the NAS article, I realized how important it is to estimate bird numbers accurately and keep track of bird populations. I thought it would be a good idea to test traits, skills and characteristics in people that might affect bird counting accuracy. Some of those traits, skills and characteristics that I chose to test included biologist/ bird watcher, male/female, use of caffeine within five hours/no caffeine within five hours and artist/scientist. I wanted to know if there were any differences between these groups. I reviewed the proceedings of an International Symposium held in Asilomar, California called Estimating Numbers of Terrestrial Birds (Ralph, J.C. and M.J. Scott, 1980). I checked to see if any of the papers had used computer simulations to improve estimating accuracy and found that none did. This is probably because the paper is dated 1980 and computers were just starting to be used at that time. I did not find any other literature that referenced use of computer simulations to improve bird counting accuracy (other than the Jack Hodges, Wildlife Counts computer simulation, which I used in my experiment). Within these same proceedings, Kepler and Scott (1980) described that variability can be reduced by training observers. I wanted to see if Wildlife Counts could improve estimation accuracy. A presentation by Harrington in 1999 stated that people counting birds tend to underestimate when large numbers of birds are viewed. I wanted to use my data to see if that principle held true.

Fig. 1. Example of Simulation Screen. Guess how many birds are there!

240 Colorado Birds Fall 2015 Vol. 49 No. 4 Methods and Materials For this experiment, I designed four different tests using the Jack Hodges computer model/simulation Wildlife Counts. The model shows simulated images of birds while it knew the exact number of birds on the screen. For all tests the participants were told that the range of birds was 50-600. For my experiment, I used the “Swans on a Lake” simulation (Fig. 1). I was able to obtain 32 participants for this project, and their results were kept confidential. For Test 1, the participants were asked to look at five screens, all with different numbers of birds in them, for a certain amount of time, and then write down their estimate after each screen was shown. This was considered the “pre-training” test, and was used to show how well the participants did without any training. Test 2 was used as the training session. The participants were shown screens with 20, 50, 100, 300, and 500 birds in them, and were told the actual number. This helped the participants cali- brate their eyes. Then, participants were shown five more screens of birds. They wrote down their estimates and then were shown the actual number of birds in the image immediately. This was used to let the participants know how well they were doing and what kind of changes they needed to make to increase their estimating accuracy. Test 3 was the “after-training” test. The participants were again shown five computer screens, after which they would write down their estimate. We did not tell the participants that the numbers of birds were exactly the same in Test 1 and Test 3. This allowed me to see if there was improved accuracy after training because the actual numbers were held constant. Test 3 was used to determine if the participants’ accuracy improved after training. Test 4 was a series of three actual bird photographs. I used Corel Photo Paint Software to pre-count and modify bird numbers in the photos so that each photo matched the number of birds in one of the screens in Test 1 and Test 3. The participants would be shown the three photos, and then write down their guess. This test was used to show how accurately the participants could estimate real birds, after all the simulations. This allowed me to compare the photo bird number to a corresponding simulation number since they had the same number of birds.

Results There are two primary statistics used throughout this experiment. One is the average estimate for a group. For example, if 10 biologists write down their estimates, an average can be produced. If 10 bird-

Colorado Birds Fall 2015 Vol. 49 No. 4 241 watchers provide estimates for that same screen, another average can be produced. This is comparing actual bird estimates that participants made, and is usually done within a single screen of a known number of birds. Averages therefore can be compared among groups or to actual numbers. Another statistic I call the “absolute error” of an estimate. The plain and simple way to define absolute error is the number of birds, either above or below, that the participant guessed compared with the actual number of birds. Absolute error is used to determine the error for a participant across the five screens. For example, if a participant

Table 1: Summary of Group Analysis.

Summary of Group Analysis For Test 1 and Test 3 Average Absolute Average Absolute Error Group/Comparison* Error for First Significance** for Second Group Listed Group Listed All T1 vs. All T3 567 314 Extremely

Bio T1 vs. BW T1 510 606 Not Bio T3 vs. BW T3 285 334 Not Bio T1 vs Bio T3 510 285 Very BW T1 vs. BW T3 606 334 Extremely

Male T1 vs. Female T1 529 597 Not Male T3 vs. Female T3 269 350 Not Male T1 vs. Male T3 529 269 Extremely Female T1 vs. Female T3 597 350 Very

Caf T1 vs. Ncaf T1 507 621 Not Caf T3 vs. Ncaf T3 318 311 Not Caf T1 vs. Caf T3 507 318 Significant Ncaf T1 vs. Ncaf T3 621 311 Extremely

Art T1 vs. Sci T1 659 526 Not Art T3 vs. Sci T3 338 305 Not Art T1 vs. Art T3 659 338 Very Sci T1 vs. Sci T3 526 305 Extremely *Abbreviations Include: Bio=Biologist; BW=Bird Watcher; Art=Artist; Sci=Scientist; Male=Male; Female=Female;T1=Test 1; Caf=People who had caffeine; Ncaf=had no caffeine; T3=Test 3 ** Categories include: not significant=<90% confidence; significant=90-98% confidence; very significant=98-99% confidence; extremely significant=>99% confidence

242 Colorado Birds Fall 2015 Vol. 49 No. 4 The author presenting her poster, “Do Certain Traits, Skills, or Characteristics Affect Bird Estimating Accuracy, and Can a Computer Model Improve Estimating Accu- racy? You Can Count on it!” estimates that there are 250 birds on the screen when there are actually 412 birds, the absolute error (expressed as a positive number) would be the difference, in this case 162. Adding the absolute error for each of the five screens, you get the total absolute error for that person, which might be 470. If another person’s total absolute error was 325, then that person’s total error was lower. The total absolute error could be added together and averaged for each group. It should be noted that the Hodges simulation allows for the cancellation of errors. I chose not to allow cancellation of errors because it is like shooting two arrows at a bull’s eye, hitting 10 inches high, and then 10 inches low. The two hits, high and low, should not make a bull’s eye. I used GraphPad, QuickCalcs 2014 to run my t-tests to compare means and determine significance. The analysis used both paired and unpaired samples. Table 1 lists the summary of group analysis. It shows one group compared to another (example: male vs. female), and also one group compared to the same group (example: male Test 1 vs. male Test 3). It also shows the significance of the averages for each group. Fig. 2 shows how each group improved after training, and the reduction in their errors.

Colorado Birds Fall 2015 Vol. 49 No. 4 243 Table 2: Test 3 vs. Test 4 Results.

Compare Simulated Screens to Real Bird Images: Average Estimates for All Participants Test 3 vs. Test 4

Test 3 (76 birds) Test 4 (76 birds) Significance Average Estimate Average Estimate

78 76 Not significant

Test 3 (536 birds) Test 4 (536 birds) Significance Average Estimate Average Estimate

451 315 Extremely significant

Test 3 (132 birds) Test 4 (132 birds) Significance Average Estimate Average Estimate

118 143 Significant

Fig. 2: How each group improved after training, and the reduction in their errors.

Table 2 shows the Test 3 vs. Test 4 results for each screen. Test 3 used simulated bird screens compared with Test 4, which used real bird photographs of the same number of birds.

Discussion and Conclusions Did Traits, Skills or Other Characteristics Have an Effect on Bird

244 Colorado Birds Fall 2015 Vol. 49 No. 4 Estimating Accuracy? Table 1 shows the differences in one group vs. another. For example, were males more accurate than females? In all cases (biologist vs. bird watcher, male vs. female, caffeine vs. no caffeine, artist vs. scientist) there were no significant differences between any of the groups. This means that traits, skills and characteristics don’t significantly affect counting accuracy. It also means that any person, regardless of characteristics, can potentially improve bird-counting accuracy through training. How Did Accuracy Change From Simulation Screens to Real Life Bird Photographs? By testing the participants using real bird photographs compared to the simulation screens, I found out that when numbers are low, people are more accurate with estimating, as shown in Table 2. As numbers of birds in the photographs increased, there were significant differences between simulation screen estimates and real bird photo estimates. This may be due to the fact that there are more challenges when estimating real bird numbers. Difficulties such as background, types of birds, overlapping birds, and density may all affect bird estimating accuracy. Over and Underestimation. Harrington (1999) said that people tend to underestimate numbers of birds in large flocks, and my findings are consistent with that statement. In Test 1, 85 percent of the estimates were lower than the actual number and in Test 3, 72 percent of the estimates were lower. I believe that the training had to do with the change in percentages. Did the Jack Hodges Computer Simulation Wildlife Counts Improve Bird Counting Accuracy? Table 1, line one, shows the absolute errors for all of the participants in Test 1 and Test 3. As you can see the participants made extremely significant improvements after training (error was reduced). This data agrees with Kepler, et al. (1980) in that training reduced bird counting variability. Bird counters around the world should consider using the online or purchased editions of Wildlife Counts computer simulation model to improve their bird counting accuracy. The model is available at wildlifecounts.com. Why Accurate Bird Estimating is Important. In the coming years, bird populations are expected to decline because of climate change. With all of these potential changes in bird populations, accurate bird estimates and population data will be very important to the future of these species. Using the Jack Hodges Wildlife Counts computer simulation, most participants’ estimates improved. Although there were no specific characteristics that effected bird estimating accuracy, training participants with a computer model did improve accuracy, and that may be the future for keeping precious bird species accounted for and protected!

Colorado Birds Fall 2015 Vol. 49 No. 4 245 So how many birds did you guess were in Fig. 1? There were actually 360 birds!

Acknowledgements First of all, I would like to thank all of the participants who contributed to my experiment. Thank you as well to Mr. Jack Hodges for providing the simulation software. I would also like to thank my teachers, Mrs. Gina Randolph and Ms. Loree Harvey, for being so helpful. And last but not least, I would like to thank my family, especially my dad, for helping me whenever I needed it. So thank you all, I couldn’t have done it without you!

Literature Cited “Bird Counting 101.” eBird. Audubon and Cornell Lab of Ornithology, 23 Feb. 2012. Web. 29 Sept. 2014. . Harrington, B. (1999, July 21). Estimating Numbers of Birds in Flocks. Retrieved 2015, from www.audubon.org/sites/.../estimating_flocks.p.. A power-point presentation. Hodges, J., 2013, Wildlife Counts. A training tool for wildlife population estimation. A computer simulation computer simulation. Wildlifecounts.com Kepler, C., & Scott, M. (1980). Reducing Bird Count Variability by Training Observers. In: Estimating Numbers of Terrestrial Birds, C. John Ralph and J Michael Scott, Editors, Proceedings of an International Symposium held at Asilomar, California, 1980, 366-371. Retrieved February 2, 2015, from https://sora.unm.edu/sites/default/files/journals/sab/ sab_006.pdf Nijhuis, M. (2014, September 1). A Gathering Storm for North American Birds. Audu- bon, 25-32. Volume 116 QuickCalcs , T-Test Calculator. (2014). Retrieved December 1, 2014, from http://www. graphpad.com/quickcalcs/ttest1.cfm Ralph, J.C. ad J.M. Scott, 1980. Estimating Numbers of Terrestrial Birds. Proceedings of an International Symposium, Asilomar, California. Cooper Ornithology Society, Studies in Avian Biology No.6. 641 p.

Alyssa H. Rawinski, [email protected]

246 Colorado Birds Fall 2015 Vol. 49 No. 4 THE HUNGRY BIRD

A Loggerhead Larder

Dave Leatherman The job opening is that of biological technician for a natural resource agency with land management responsibilities on the northeastern plains of Colorado. It’s the kind of job I would have jumped at back in the 1970s with a formal description that might read something like this: “Inventory, collect and curate fauna from within an assigned area of native grassland. Applicants must be familiar with the life histories and diurnal habits of the insects, small mammals, passerine birds, reptiles and amphibians of Weld and surrounding counties. Work conditions include variable and potentially harsh weather, venomous snakes, barbed wire, cattle (including bulls), truck traffic and plants with thorns. Must be willing to have work habits and performance evaluated by at least one other technician on a regular basis. Pay commensurate with education and experience.” In the text and photographs that follow, I intend to make a case for the United States Forest Service or Colorado Department of Parks and Wildlife hiring a certain male Loggerhead Shrike (Lanius ludovicianus) to fill the job opening described above. This one bird, operating on Weld County Road 37 between Roads 114 and 122 during the summer of 2015, would not only warrant hiring, but a promo- tion, a letter of commendation and a 2016 rehire. In fact it did such a good job of collecting and displaying biota that I was in awe of its appreciation for diversity and was taken aback on more than one oc- casion by its lethal efficiency. He was an exhibitionist in every sense of the word. No doubt, as soon as humans began noticing shrikes in the natural world around them, their habit of sticking objects on sharp things became a source of curiosity. Our grandparents called them “butcher birds” and probably never used benign descriptors in their company. From our perspective, impaling creatures on sharp objects, especially when often the stickees are alive at the time of the act, and not eaten right away, or at all, can easily be interpreted as “mean” or “macabre.” So why do they do it? These unique raptorial songbirds have sharp, falcon-like beaks equipped with a pair of tomial teeth on the maxilla for severing the spinal columns of their prey (Craig 1978). And like hawks they have the skills to discover and catch things. But why stick them? The answer seems partly attributable to their relatively weak feet that lack talons (Yosef 1996). In essence, the act of prey consumption is made easier by use of sharp objects, both natural and unnatural, that function as “forks.”

Colorado Birds Fall 2015 Vol. 49 No. 4 247 Fig. 1. Redshank grasshopper impaled intact by Loggerhead Shrike as found 18 June 2015 on Weld CR37 0.9 miles north of CR114. This particular species is perhaps the most commonly utilized insect by Fig. 2. Redshank grass- shrikes on the eastern plains of CO. hopper. Legs removed by shrike to make the handling and impaling easier.

Fig. 3. Robust camel cricket, second most commonly impaled insect in many Fig. 4. A second species parts of eastern Colorado. of robust camel cricket.

Fig. 6. Ground beetle Fig. 5. Field cricket. head and thorax. Fig. 7. Darkling beetle.

248 Colorado Birds Fall 2015 Vol. 49 No. 4 But there’s more to impaling potential food items than that. A common theme throughout the Animal Kingdom is males showing off in various ways to females as a prelude to reproduction. The Log- gerhead Shrike, the only one out of 30 true shrike species in the world that occurs wholly within North America, is mostly migratory throughout the northern part of its range, including Weld County, CO (Kingery 1998, Craig 2014, Yosef 1996). In spring males arrive on breeding grounds before females. Usually for a period of weeks af- All photos taken on either 18 June or 22 ter the males arrive, an increasing June (except for the one showing a pellet) frenzy of “bulletin board” activity by Dave Leatherman within 0.9 and 1.1 occurs, with these hormone-driven miles north of Weld CR114 along CR 37. individuals impaling things all over territories they think would be productive places to raise families. Colorado Breeding Bird Atlas I fieldworkers documented shrike courtship as basically a May activity (30 April to 6 June) (Kingery 1998). During this timeframe, males show off their skills at providing food for prospective mates and their resultant broods. During the two mid-June visits in this episode, I believe the nest was occupied and that the adults were in the process of whittling away at the male’s stash of food. I have long been enamored of shrikes and their penchant for impaling prey. Odd objects on barbed wire fences catch my eye. See- ing an impaled grasshopper here, a cricket there is not uncommon anywhere in Colorado where shrikes breed, and particularly not at a known stronghold like the Pawnee Grasslands. But I wasn’t prepared for what I saw on 18 June 2015 along CR37 north of CR114 between the Owl Creek Bridge and the Central Plains Experimental Range Headquarters complex to the north. There on metal fence barbs on both sides of the road within about 100 meters both north and south of a lone Siberian elm (1.1 miles north of CR114), was an exceptional assortment of shrike-impaled biota. I did not do an exact count but would estimate at least 75 objects. Insects were by far the most common animal group impaled. Most were what I have learned to be the “favorite” of shrikes on the eastern plains of Colorado, the redshank grasshopper (Xanthippus corallipes) (Figs. 1 & 2). These large, band-winged hoppers (family Acrididae, subfamily Oedipodinae) are widely distributed in the West and usually abundant on the arid plains. Their bright red inner “thighs” on the hind jumping legs are distinctive, although my friend Tim Mc- Nary, an orthopteran expert extraordinaire, reminds me that there are a few other lookalike species in this genus. Next in abundance among the six-legged larder were large crickets

Colorado Birds Fall 2015 Vol. 49 No. 4 249 in the family Gryllacrididae, mostly reddish-brown but some creamy- tan. These so-called robust camel crickets (Udeopsylla robusta) (Fig. 3) and perhaps another species (Daihinia brevipes?) (Fig. 4) live in burrows in the soil or hide under objects like dry cow pies and are most active at night (Cranshaw 1995). Because male crickets are more apt to forage away from burrows (for other insects and a limited amount of plant material), it is likely more males are caught and impaled by shrikes than females, however, this needs to be verified. Several black field crickets of both genders Gryllus( sp.) decorated the fences (Fig. 5). There was one large predaceous ground beetle head (family Ca- rabidae, genus Pasimachus) (Fig. 6) and one medium-sized darkling beetle (family Tenebrionidae, probably Eleodes sp.) (Fig. 7). As for reptiles, on 18 June the only representative taxon were four, small (about half-grown), intact, Short-horned Lizards (Phrysonoma hernandesi) (Fig. 8). On 22 June the number of “horny toads” was the same but it was obvious something, presumably a shrike, had eaten part of the upper torso of one, accessed from the underside (Fig. 9). Added to the reptilian ranks of the run-through were a Lesser Earless Lizard (Holbrookia maculata) (Fig. 11) and a small Western Hognose Snake (Heterodon nasicus) (Fig. 12). This lizard, multiple individuals of which I have seen impaled in other eastern CO locations, was partially shriveled, but its inner organs appeared to have been at least partly removed. The head end of the snake was missing. Loggerhead Shrikes are known to impale small mammals, at times in good numbers, but never as commonly as their relative, the North- ern Shrike (Lanius excubitor) (Yosef 1996). The remains of only one mammal hung from a barb in this situation, what I think was a young Thirteen-lined Ground-Squirrel (Ictidomys tridecemlineatus) based on the shape of the skull and the color of hairs still attached to the carcass (Fig. 13). What seemed exceptional to me about this situation, in addition to the sheer number of objects, was what this shrike imposed on other birds. In addition to finding adults, it also found new nestlings, some that were essentially featherless (Figs. 15 & 16). Not only did it find birds smaller than itself, it apparently killed one bigger than itself, a juvenile Western Meadowlark (Sturnella neglecta) (Fig. 14). Some of its bird victims were affixed to a wire whole, others were beheaded. I must admit that on 18 June, even as a lifelong biologist, coming across the beautiful, unbloodied head of a Brewer’s Sparrow (Spizella breweri) with its lifeless, hollow stare, stopped me in my tracks (Fig. 17). I later found a headless Brewer’s Sparrow body over a hundred meters away that may have been its match. This shrike was not mess-

250 Colorado Birds Fall 2015 Vol. 49 No. 4 Fig. 8. Young short-horned lizard intact on 18 June 2015. Fig. 9. Same individual short- horned lizad as shown in Fig. 8 as discovered on 22 June 2015 showing partial consumption after being impaled.

Fig. 10. Short-horned lizard head as discovered on 7 August 2015.

Fig. 11. Lesser earless lizard. Fig. 12. Western hognose snake.

Colorado Birds Fall 2015 Vol. 49 No. 4 251 Fig. 13. Unknown mammal (probably young 13-lined ground-squirrel). Skull showing black mouth cavity at lower left part of carcass. Fig. 14. Young Western Meadowlark, presumably impaled by shrike.

Fig. 15. Nestling bird (species unknown). Fig. 16. Nestling bird (species unknown).

Fig. 18. Pellet, presumably of shrike, Fig. 17. Brewer’s Sparrow head. impaled by shrike.

252 Colorado Birds Fall 2015 Vol. 49 No. 4 ing around. Altogether I would estimate I saw a total of 10 impaled birds, most quite young, that had to have been taken from nests. So a total of about 75 objects: 6 reptiles, about 10 birds, one mammal and roughly 58 insects, most of the latter group being rather large grasshoppers and crickets. The major differences in the larder between 18 and 22 June were that many of the objects that were whole on the first visit were partially or mostly consumed on the second visit. Plus there was the addition of two reptile species. The male shrike doing the impaling seemed to accomplish what were likely his two primary objectives: storing food for later consumption and attracting a mate. As a follow up, I revisited the site on 7 August 2015. Mostly I drove the stretch of road on either side of the nest tree, but also walked some of it. The only identifiable object I found from the June larder was the head of one Short-horned Lizard (see Fig. 10). A re- gurgitated bird pellet, which appeared to be the right size for a shrike, was also new on the fence very near the shrikes’ nest elm (Fig. 18). And yes, I saw at least three fledged shrikes. Asking them the question, “who’s your daddy?” seemed unnecessary. They were hunting on their own, usually by flying down to the ground from the top strand of the fence. Twice I observed them returning to the fence with small insects, probably grasshopper nymphs, which they held against the wire with a toe, and consumed on the spot. In closing, my curiosity keeps returning to that impaled Brewer’s Sparrow head and those nestling birds. These objects perhaps fit within the standard reasons for impaling by shrikes cited in the literature, but struck me as possibly serving a third purpose–that of in- timidation. It reminded me of something I saw once as a kid in a Na- tional Geographic Magazine involving cannibals in Borneo who, as a warning to would-be intruders, displayed heads on sticks. If whole birds are usually impaled (as was the meadowlark and most of the nestling birds), why did this male shrike go to the trouble of carefully beheading a sparrow and then, apparently, place the resultant two body parts at opposite ends of his territory? Did this, along with the impaling of nestlings, convey to other species nesting, or even considering nesting within this shrike’s territory, that competing with him for food resources might be a bad idea? No way to prove any of this, but one has to wonder. Regardless of answers to these last conjectures, if I was an HR person looking to fill a biodiversity surveyor position, and a male shrike was sitting across the desk, I’d ignore the bad recommendation in the application folder from somebody’s grandmother. Hire him!

Colorado Birds Fall 2015 Vol. 49 No. 4 253 ACKNOWLEDGMENTS I thank Tim McNary and Dr. Boris Kondratieff, both affiliated with the C.P. Gillette Museum of Arthropod Diversity at Colorado State University, for assisting with identifications of impaled insects.

LITERATURE CITED Craig, R. B. 1978. An analysis of the predatory behavior of the Loggerhead Shrike. Auk 95:221-234. Craig, Susan. 2014. Movements, migration and breeding by Loggerhead Shrikes (Lanius ludovicianus) in eastern El Paso County, Colorado. CO Birds 48(2):266-271. Cranshaw, Whitney and Boris Kondratieff. 1995. Bagging big bugs. Fulcrum Publishing, Golden, CO. Kingery, Hugh E. (ed.). 1998. Colorado breeding bird atlas (I). Co-published by Colorado Bird Atlas Partnership and Colorado Division of Wildlife, Denver. Yosef, Reuven. 1996. Loggerhead Shrike (Lanius ludovicianus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithol- ogy; Retrieved from the Birds of North America Online: http://bna.birds. cornell.edu/bna/species/231

Dave Leatherman, [email protected]

254 Colorado Birds Fall 2015 Vol. 49 No. 4 IN THE SCOPE

Ravens in Colorado: An Impossible Field Identification?

Tony Leukering Colorado hosts two species of ravens, the holarctic Common Raven (Corvus corax), grist for many an authorial mill (including that of Poe), and the limited-range Chihuahuan Raven (Cor- vus cryptoleucus), which has probably seen little, if any, poetry or prose written about it. Common Raven is represented in Colorado by the subspecies sinuatus. Its range is largely restricted to West Slope and montane habitats in Colorado, including on the Mesa de Maya, which extends from Las Animas County into Baca, Bent and Otero counties. Common Ravens are also regularly seen on the northwest plains adjacent to the foothills, typically west of I-25 though with some exceptions [especially westernmost Arapahoe County and the vicinity of Rocky Mountain Arsenal N. W. R. in Adams County (eBird 2015)] and on the plains in the Arkansas River drainage. The Chihuahuan Raven’s range is something of an enigma. Henshaw (1875) reported the species as widespread on the Colorado plains during the period of American Bison slaughter (mid- to late 1800s), but its range contracted greatly following the near extinction of wild bison in the United States, possibly returning to pre-slaughter range (Aiken and Warren 1914). The first Colorado Breeding Bird Atlas presented the breeding range of Chihuahuan Raven as restricted to 11 southeastern counties: south from southern Pueblo County east to southern Prowers County, with scattered records north through Crowley and Kiowa counties and single records from the southern borders of El Paso and Chey- enne counties (Nelson 1998). With the great increase and intensity of birding efforts in the state that began in the early 1990s (pers. obs.), sightings of Chihua- huan Ravens outside of the range mapped by Andrews and Righter (1992) and Nelson (1998) began to accumulate and seems to be accelerating (pers. obs.). There are eBird (eBird 2015) reports from 38 of the state’s 64 counties, including those as far north as Routt, Larimer and Weld and as far west as Mesa and Montezuma. The vast majority of these far-flung reports is supported by little or no definitive details, and therefore is not included in the public eBird data. But, what constitutes definitive details for two species so similar, that are entirely black in both plumage and soft-parts coloration? Aye, there’s the rub.

Colorado Birds Fall 2015 Vol. 49 No. 4 255 Back-cover Photo, Part I The photograph on the back cover of this issue was taken in July 2015 and serves as an excellent illustrative piece for this essay. Clear- ly it’s a raven, but which species? Perhaps the following will assist in the bird’s identification.

Raven Identification “Distinguishing Chihuahuan Raven from small Common individuals can be extremely difficult.” (Sibley 2000) As indicated above, raven identification is at times, “extremely difficult.” In fact, some birders (including yours truly) consider this the single most-difficult identification quandary in the ABA area. Yes, there are other very difficult groups, but how many are of such large birds that are often seen so well? My personal experience with raven identification in southeastern Colorado followed an interest- ing course. I first considered them quite difficult, then fairly straight- forward as I got more experience with them. However, as additional experience piled up, I’ve forced myself to keep an open mind and have now reverted, considering them to be at the very least quite difficult to separate, if they’re definitively and reliably separable at all. Due to the near-complete lack of plumage characters permitting sepa- ration (both are all black), birders in the New World area of sympatry or nearby have had to resort to shape and vocal clues to attempt raven identification, with the various individual characters discussed below. Pieplow (2014) discussed the vocal aspects of raven identification, and given the difficulty of discussing vocalizations in a print medium, I highly recom- mend reading (and listening to) that post, including the comments. Before tackling the individual characters that are typically used to attempt raven identification, please note the following caveats with regard to size. While Common Raven averages considerably larger than Chihuahuan Raven, there is enough variation in overall size in both species as to make an in-the-field distinction between a large Chihuahuan Raven and a small Common Raven problematic. Ad- ditionally, some of that variation in size is due to sex, with males in both species being larger than females in nearly all characters. In the treatment of individual characters below, all statements are of relative size. You may also refer to the data presented in Table 1. As we all know, correctly assessing size in the field without some comparison, direct or indirect, is fraught with uncertainty. A direct comparison of size with some other bird species may be useful, but only with a suitable yardstick: An American Crow mobbing a raven would provide a useful comparison, but a much smaller bird, such as a Western King- bird, would not, due to the significant size disparity.

256 Colorado Birds Fall 2015 Vol. 49 No. 4 Fig. 2. Two each Chihuahuan (left) and Common (right) Ravens (specimens at Mu- seum of Vertebrate Zoology, CA). Photo by Peter Pyle

Bill Shape Common Raven bills are longer and, generally, deeper than are those of Chihuahuan Raven. With the overlap in bill depth between the two species, but the absolute greater length of bill in Common Raven, Common Raven generally appears to have a longer bill relative to depth than that of Chihuahuan [midpoints of extreme ratios are length being 2.55x greater than depth in Chihuahuan, 2.81x in Common (Ratio of C:D); Fig. 1]. However, without direct comparison, this character is probably nearly useless in field situations.

Nasal-bristle Length The nasal bristles are the feathers that lie atop the basal part of the bill in all members of the genus Corvus, and much is made of this character’s usefulness in raven identification by some birders. The extent of the bristles on Chihuahuan is generally more (often distinctly more) than half the bill length, while that of Common is generally less than half the bill length. This would mean that individuals with nasal-bristle length of about half the bill length are not identifiable using just this character. Additionally, there has been suspicion raised

Colorado Birds Fall 2015 Vol. 49 No. 4 257 about the true usefulness of the character in Colorado (B. Maynard pers. comm., S. Mlodinow pers. comm.), as most ravens assumed to be Chihuahuans in Colorado seem to lack the excessive nasal bristles typical of the species in the core of its range (Fig. 1). Whether this is due to misidentification of ravens on our part, variability in this character on the part of Colorado Chihuahuan Ravens or, egad!, a result of hybridization of ravens in Colorado is not determinable at this time. Suffice it to say that this character may not be particularly useful in the field, at least not in Colorado.

Color of the Base of Neck and Breast Feathers Chihuahuan Raven used to be known by the moniker White- necked Raven due to the fact that the base of the neck and breast feathers is white versus the gray of the same feather bases in Common Raven. However, given that looks at these feather bases good enough to provide certainly of the color just about requires having the bird in question in the hand, that means that this character’s usefulness is akin to, but probably less useful than, that of the brown neck ring in male Ring-necked Ducks. At least with the duck, if you can see the bird well enough to note the brown neck ring, you certainly have a sufficient view to note all of the other much-more-obvious identification features! In order for the white feather bases to be seen, the feathers usually need to be ruffled by the wind. Pyle (1997) presents this caution: “Beware that the throat and breast plumage differences can be subtle, particularly without direct comparison.” And that in a publication aimed at bird banders with birds in the hand! Some observers report seeing single Common Ravens in very windy conditions exhibiting apparent white bases to these feathers in direct comparison with gray feather bases on other Common Ravens in the same flock (S. Mlodinow pers. comm.).

Throat Shagginess This character is created by the long feathers of the throat, with Chihuahuans having, generally, shorter such feathers than do Com- mons. However, given the overlap in the range of values in the two species, and the difficulty in correctly assessing the feature in the field [the non-overlapped part of the Common range is only 14 mm (0.55 in.)], this is probably another character with limited field usefulness.

Wing Length and Shape Common Raven may have longer wings, relative to overall size, than does Chihuahuan [at least Sibley (2000) seems to present the

258 Colorado Birds Fall 2015 Vol. 49 No. 4 species that way], but if so, any difference is probably not reliably detectable in the field. Sibley (2000) also presents a different wingtip shape in the two species, with Chihuahuan wings more square- or round-tipped versus more pointed Common Raven wings, but this difference is much less apparent in Sibley (2014). Although Pyle (1997) presents a wingtip metric for Chihuahuan (the relative lengths of primaries 5 and 9), no such measurement is given for Com- mon.

Tail Shape With the exception of voice, tail shape is probably the single character used most often by birders to identify ravens to species in Colo- rado (and elsewhere in the New World). In general, Chihuahuan Ravens have rounded tails and Common Ravens wedge-shaped tails. However, tail shape seems to be a factor associated with sex, with females of both species possibly being rounder-tailed than are males. Thus, as with overall size, male Chihuahuans and female Commons

Table 1. Chihuahuan and Common Raven measurements1. Measurements are in mm; sample sizes (where provided in source literature) are in parentheses.

Chihuahuan Raven Common Raven (sinuatus) Character Female Male Female Male Wing chord 321-361 (100) 332-380 (100) 390-425 (19) 412-440 (17) Tail length 179-205 (20) 181-214 (20) 218-242 (19) 225-250 (17)

All All Wing chord 321-380 (200) 390-440 (36) Tail length (A) 179-214 (40) 218-250 (36) r1-r62 (B) 25-45 34-633 Ratio of B:A4 0.14-0.21 0.16-0.25 Length of longest 29-42 39-56 throat feathers Bill length5 (C) 49.5-59 63-71 (14) Bill depth6 (D) 20-22.5 21.7-26.1 Ratio of C:D4 2.48-2.62 2.72-2.90 1 All values from Pyle (1997) except those of Bill length of Common Raven are from Oberholser (1918) 2 The differences in length between innermost (r1) and outermost (r6) rectrices, a measure of "wedged-ness" 3 Pyle (1997) provides this measure for the species as a whole, not for sinuatus, which is a medium-sized subspecies. 4 Range obtained by comparing minimum value of both variables and maximum value of both variables 5 Exposed culmen measurement; that is from base of bill to tip 6 Measured at nares

Colorado Birds Fall 2015 Vol. 49 No. 4 259 may very well overlap in tail shape. Yes, those nearly diamond- shaped tails of large, long-tailed male Commons probably provide an excellent identification clue, but round tails do not do much for us. Unfortunately, Pyle (1997) did not provide a range of values of “wedged-ness” (r1-r6; the higher the value, the more wedge-shaped) for the subspecies found in Colorado, so the range provided in Table 1 includes all four North American subspecies. Because sinuatus is a medium-sized subspecies, the larger and smaller values of that range are probably not found in Colorado. Also, it is probably worth men- tioning that factors including how spread the tail is as well as the degree of molt and/or wear of the tail can impact one’s impression of tail shape.

Back-cover Photo, Part II Are you ready to tackle the identification of this raven using the above criteria? Size: With nothing in the picture other than raven and blue sky, we cannot determine the bird’s overall size. Bill shape: With the bird’s bill being open, we cannot adequately assess the depth of the bill, thus the ratio of length to depth cannot be determined. (There do seem to be some odd aspects of this bird’s bill, which are discussed below.) Nasal-bristle length: Despite the low angle of the photo, we can see the extent of the nasal bristles, which appear to lay on about half the length of the top of the bill, so that character is not useful to identify this individual. Color of the base of neck and breast feathers: There seem to be some gray bits in the bird’s neck/breast plumage, which might suggest Common Raven as the identification. However, this appearance is not due to ruffled feathers and exposure of the feather bases to the light (more on this below). Throat shagginess: The throat is shadowed in the picture and no shagginess is evident (more on this below). Wing length and shape: The wings seem fairly short and wide, at least to me, and the wingtip seems an odd combination of pointed [long distance between the tip of the outermost (p10) and longest primaries) and squared-off (p6-p8 being of the same length). Perhaps this feature points toward Chihuahuan (more on this below). Tail shape: The tip of the tail is smoothly rounded, with no sug- gestion of a wedge shape, though the absolute tail length seems a bit long to my eye. This character may be a wash, or could lean toward Chihuahuan.

260 Colorado Birds Fall 2015 Vol. 49 No. 4 Ageing Ravens I know…why would you want to? Well, as with gulls and many other bird species, determining the bird’s age can instruct on the identification process. At least with ravens, we have to deal with only two age classes, adult and juvenile/immature (birds in their first plumage cycle; Leukering 2010). The pictured bird is readily aged as an immature by at least three features. 1) The gape and the roof of the mouth (the latter of which we can see well thanks to the open bill) are pale and contrast with the black of most of the outside of the bill. Adults lack such an obvious gape (and what they show is black) and have the roof of the mouth black. 2) The body shows a mix of feather generations, with scattered clumps of gray-brown neck, breast and belly feathers that are remnants of juvenile plumage. 3) The color of the primaries and secondaries are a grayish-brown that produces a strong contrast with the black formative (Leukering 2010) feathering of the wing linings. Knowing that the picture was taken in July, and knowing that there has been extensive replacement of juvenile body plumage, but no replacement of flight feathers, we can determine that this bird was hatched this year and is, at best, a few months old. Additionally, because the bird is still wearing its juvenile flight feathers, we might want to consider any wing-shape characters to be suspect as wing shape in juveniles/immatures of many bird species differs from that of adults of the same species (e. g., many or most eagle species, most or all Buteo species, Little Gull). Taking into account all of the above, I find that there are no strong clues to allow identification of this raven. Well, there is one, but unless you looked ahead, you wouldn’t know that the photo was taken in northwestern Montana, about ten miles from the U.S. border with Canada. The location should nicely rule out Chihuahuan Raven. While range-based identification may not be very satisfying, birders use that criterion all the time. A silent wood-pewee seen in Utah is a Western, but seen in Virginia it’s Eastern. Yet as birders state all the time, “birds have wings” and the ability to show up where they are not “supposed” to be, so why is the pictured bird not documentation for Montana’s first record of Chihuahuan Raven? Despite the aforementioned poorly supported scattering of eBird reports of Chihuahuan Raven nearly the length and width of Colo- rado, the vast majority of reports of the species come from that part of the state where they are “supposed to be.” Colorado birding has the belief that, at least in the breeding season, Chihuahuan Ravens occupy the prairie, Common Ravens the foothills and mountains, with a bit of overlap on the prairies within a few miles of “suitable”

Colorado Birds Fall 2015 Vol. 49 No. 4 261 Common Raven habitat. This creates the situation in which ravens on the plains in summer are identified as Chihuahuans and those in the mountains and foothills as Commons, a circular-reasoning situation if ever I saw one. Raise your hand if you have ever identified a distant summer raven on the plains as a Chihuahuan, despite the fact that you discerned no useful field characters. Did your hand join mine, which was wildly waving in the air? Why is it that we are willing to use range maps as the sole feature to identify individuals of some difficult groups, but not of other groups? Consider this essay a plea for more thought and care in raven identification in the state, which should lead to more extensive use of the “raven sp.” category in field notebooks and in eBird.

Acknowledgments I greatly appreciate discussion of raven bill morphology with and unpublished data on such from Peter Pyle. I also thank Steve Mlodinow for a thoughtful review of a previous draft of this essay.

Literature Cited Aiken, C. and E. Warren. 1914. Birds of El Paso County. Colorado College Publ. General Series 74, Science Series No. 13. Colorado Springs, CO. Henshaw, H. W. 1875. Report on the ornithological collections made in portions of Nevada, Utah, California, Colorado, New Mexico, and Arizona, during the years 1871, 1872, 1873, and 1874 in report upon geographical and geological explorations and surveys west of the one hundredth merid- ian, vol. 5. U. S. Government Printing Office, Washington, DC. Leukering, T. 2010. Molt and plumage: A primer. Colorado Birds 44:135- 142. Nelson, D. L. 1998. Chihuahuan Raven. In Colorado Breeding Bird Atlas (H. E. Kingery, ed.), Colorado Bird Atlas Partnership and Colorado Divi- sion of Wildlife, Denver, CO. Pieplow, N. 2014. Common vs. Chihuahuan Ravens. Earbirding.com (http:// earbirding.com/blog/archives/4736). [Accessed 4 August 2015] Pyle, P. 1997. Identification Guide to North American Birds, part I. Slate Creek Press, Bolinas, CA. Sibley, D. A. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York. Sibley D. A. 2014. The Sibley Guide, 2nd ed. Alfred A. Knopf, New York.

Tony Leukering, [email protected]

Fig. 1 (back cover). Immature Common Raven, Toole Co., MT, 30 July 2015. Photo by Tony Leukering

262 Colorado Birds Fall 2015 Vol. 49 No. 4 The Colorado Field Ornithologists’ Quarterly

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Colorado Birds Fall 2015 Vol. 49 No. 4 263 In the Scope Ravens in Colorado: An Impossible Field Identification? . . . 255