Colorado Birds the Colorado Field Ornithologists’ Quarterly

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Vol. 50 No. 2 Spring 2016 Colorado Birds The Colorado Field Ornithologists’ Quarterly

Boreal Owls in Rocky Hungry Birds Key In on Defects Lesser Nighthawks in Colorado 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, 2017, [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, 2018; 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, Boul- der, 2017*; Tony Leukering, Largo, Florida, 2018; Dan Maynard, Denver, 2017*; Bill Schmoker, Longmont, 2016; Kathy Mihm Dunning, Denver, 2018*

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

Contributors: Peter Gent, 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.

COPYRIGHT © 2016 by Colorado Field Ornithologists. Reproduction of articles is permitted only under consent from the publisher. Works by U.S. and Canadian governments are not copyrighted. The Colorado Field Ornithologists’ Quarterly Vol. 50 No. 2 Spring 2016

PRESIDENT’S MESSAGE...... 62 Doug Faulkner

ABOUT THE AUTHORS...... 65

CFO BOARD MEETING MINUTES...... 66 Larry Modesitt

CFO APPRECIATION AWARD...... 69 Joe Roller and Dave Leatherman

JOHN KIRK TOWNSEND...... 70 Bob Righter

THE HUNGRY BIRD...... 75 Dave Leatherman

STATUS OF THE BOREAL OWL...... 83 Scott Rashid

NEWS FROM THE FIELD: FALL 2015...... 88 David Dowell

IN THE SCOPE...... 105 Tony Leukering

COLORADO'S BIRD LIST...... 114 Tony Leukering

Cooper’s Hawk, Aurora, FULLY EXPOSED...... 118 Arapahoe Bill Schmoker County, 6 December 2015. Photo by LESSER NIGHTHAWK IN COLORADO...... 121 Connie Kogler Tony Leukering PRESIDENT’S MESSAGE

I love anniversaries. Not because of presents or parties, but because it helps to reset my perspective. I enjoy comparing an entity’s embry- onic beginnings with its more mature version of today. I will admit that this interest does not involve very deep thought. I won’t pretend to have a command of any of the behavioral, socio-economic, or po- litical sciences. Anniversaries do, however, give me an opportunity to reflect on change over long time- frames and to recognize changes happening in the short-term. The year 2016 marks the 50th anniversary of CFO journal publications, the first of which was published as The Colorado Field Orni- thologist No. 1 in winter 1967. That 20-page issue was a quick read, but nonetheless full of interesting articles. Paul Julian presented a me- ticulous review of Harlan’s Hawk (then considered a full species Bu- teo harlani), including its confused taxonomic origins—did John James Audubon really collect this (now subspecies), the plate of which he titled “Black Warrior”—along with a summary of plumage characteris- tics and the challenges of identifying a Harlan’s in the field. George Shier’s article “Rufous- Doug Faulkner sided Towhee Range in Colorado” summarized anecdotal evidence of that (then species’) breeding range in the state. Well known along the Front Range, it was apparently much less frequently encountered elsewhere in the state. That issue also gave a tabular summary of Colorado’s ten Christ- mas Bird Counts, noting such species as Whistling Swan, Oldsquaw, Marsh Hawk, Sparrow Hawk, Common Bushtit, and Water Pipit. In stark contrast to our current “News from the Field,” the first issue’s “Field Notes” listed just four interesting sight observations— Mourning Dove, Carolina Wren, Brown Thrasher, and Oldsquaw, all of which were noted in the Fort Collins area. The final aspect of that first issue I want to present: that year’s CFO convention was an- nounced on the inside back cover. Reservations were made by writ-

62 Colorado Birds Spring 2016 Vol. 50 No. 2 ing (that is, by hand, on paper, mailed through the post office) to the local bird club hosting the convention. The Colorado Field Ornithologists, its publications, the latest of which is published as Colorado Birds, and much of what we now “know” has changed. We no longer consider Harlan’s Hawk a species; thanks to the Colorado Breeding Bird Atlases I and II we have a much clearer picture of the (now Spotted Towhee’s) breeding distribution; the number of CBCs has grown considerably and those species names are no longer used in current taxonomy, but I would guess that most of you know to which species they now refer; the venues in which to report birds, both common and rare, are not limited to hard-copy publications; and convention registration no longer re- quires pen and stamp. I encourage old and new members to take a peek at what the journal has published. Issues dating back to April 2000, which is when we first started printing from a PDF format, are available on the CFO website under the Birding Resources tab. The CFO Board is looking at options for getting the remaining past issues online. If you have any ideas we should consider or if you would like to participate in this endeavor, please send me an email (or pen me a note and mail it). And, yet, to prove that not all changes are permanent, take a look at who the journal editor was for the earliest issue available on the website. It was none other than our new editor, Scott Gillihan. It is a pleasant treat to see that some changes are not forever. Welcome back! The journal has had three editors between Scott’s editorships, most recently Peter Burke who is stepping down from the journal but not away from involvement in CFO. Colorado Birds continued to provide outstanding content under Peter Burke’s editorship that started with the fall 2013 issue and which included an interview introducing Peter and his thoughts on the future of CFO and the journal. Not only did he bring skill and expertise to the editor posi- tion, but his thoughtful insight and perspective on other issues during Board meetings will be missed. On behalf of CFO, our many thanks to you, Peter, for your contributions to our organization, to Colorado Birds, and to Colorado birding. May you have many more sunrises, wing glimpses, and terabytes of ridiculously memorized data to sort through in the years ahead.

Colorado Birds Spring 2016 Vol. 50 No. 2 63 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.

64 Colorado Birds Spring 2016 Vol. 50 No. 2 Featured Authors

John Kirk Townsend 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.

Status of the Boreal Owl Scott Rashid is the director of the Colorado Avian Research and Rehabilitation Institute in Estes Park. He has been working with birds of prey for more than 25 years and has written two books about owls: Small Mountain Owls published in 2009 and The Great Horned Owl published in 2015. His third book, The Northern Goshawk, will be released in December 2015.

Editor’s note: The page numbering in the previous issue (Volume 50, Num- ber 1) was inadvertently carried over from the final issue of Volume 49. The 60 pages of Volume 50, Number 1 should have been numbered 1–60. The page numbering in the present issue (Volume 50, Number 2) picks up with page 61. We apologize for any inconvenience.

Colorado Birds Spring 2016 Vol. 50 No. 2 65 CFO BOARD MEETING MINUTES

23 January 2016 Boulder Open Space Mountain Parks Annex, Boulder, CO

Larry Modesitt President Doug Faulkner called the January quarterly meeting to order at 11:14 a.m. after a pre-meeting birding outing featuring a White-winged Dove. Other Officers present were Vice President David Gillilan, Secretary Larry Modesitt, and Treasurer Michael Kiessig. Directors Christy Carello, Lisa Edwards, Ted Floyd, Scott Gillihan, Mike Henwood, Bill Kaempfer, Christian Nunes, Chris Owens, and Mark Peterson also were present.

To begin the meeting, Doug wel- case of rain, and the cost of the open- comed our new editor of Colorado ing picnic has been donated by local Birds, Scott Gillihan, and noted that residents. this is a welcome return to the posi- 2. Field Trips are defined, and lead- tion of editor but for a publication ers are being determined. Some dif- that has undergone much growth. ferent trips will have broad appeal. Scott indicated he is delighted to be For example, Christian Nunes will back and welcomed the opportunity lead an “All Things Wild” trip to Pic- to continue improving the excellent ture Canyon, and trips to Kansas and publication. Oklahoma will appeal to state listers. Duane Nelson will lead a Piping Plo- Secretary’s Report: Larry Modes- ver trip, and a Sand Creek trip will itt’s minutes of the 07 November 2015 include history of the massacre there. board meeting were approved. Keynote Speaker Garth Spellman will hold a workshop. Treasurer’s Report: The board 3. Our banquet will be at the Elks reviewed Michael Kiessig’s previously Club. The board is still smarting from submitted budget and after making a the late and lengthy convention a few minor corrections, approved it. decade ago in which sleepy birders, The previous year’s heavy spending for with every appearance of a dark slide, website upgrades are no longer neces- bolted for the exits. Consequently, all sary, so we approved big increases in actions will be tightly controlled to grants for worthwhile projects. finish on time and early. 4. Paper session. Christy Carello 2016 Lamar Convention Plan- noted we have five paper speakers ning Roles and Responsibilities— lined up. Doug Faulkner 5. Registration Process and Con- 1. Facilities. Willow Creek will be vention Brochure. David Gillilan the site of the opening picnic. The pleaded for information on field trips, City of Lamar has made provisions in so that live information will be posted

66 Colorado Birds Spring 2016 Vol. 50 No. 2 by 25 February, giving people the op- Ornithologists to publicize the con- portunity to select their desired trips vention to WFO members. We expect prior to the opening of registration. high attendance and see no need to The registration process will be com- advertise. pletely online again but simplified 13. Ask Me. Chris Owens has from last year. recruited additional people to assist 6. Pricing. We decided to main- attendees in various venues. tain pricing for members at $95, still a bargain. Student prices, however, will Future 2017 Convention: The be reduced to encourage their atten- board evaluated considerations and dance, particularly for the banquet. will explore possibilities. 7. Food Service: Local birders Jane Stulp and Janeal Thompson are ne- Project Fund and Scholarships— gotiating with suppliers for breakfasts Christy Carello presented the evalu- and lunches. ations from project judges Jameson 8. Jeopbirdy. Christian Nunes Chace, Catherine Ortega, and Na- promised that the bargain-brand Jeop- than Pieplow. The board reviewed birdy system will be replaced by one each project and decided whom to that will work properly. fund, again agreeing that any person 9. Exhibitors. Larry Modesitt an- who receives a grant has the obliga- nounced that, unlike the cramped con- tion to publish results somewhere. ditions in Salida limiting the number of and space for exhibitors, this year’s Nominations—Chris Owens de- location will be spacious and conve- scribed a teleconference with Doug nient. Since the Empire Room at the Faulkner, David Gillilan, and Larry Cow Palace will be a meeting room for Modesitt to improve the process for registration, paper sessions, trip result selecting new board members. We are charts, and the BAR, attendees fre- interested in more diversity in several quently will be near exhibitors. areas, and we frequently have require- 10. Tee Shirt. Lisa Edwards an- ments for specific expertise. In addi- nounced they are on schedule and fea- tion, a Director must be hard working, ture a special bird of the area. dependable, and team-oriented. We 11. Compensation for leaders all reaffirmed that being an outstand- who are CFO members will be in- ing birder is unnecessary to be consid- creased to include free registration— ered for helping with CFO activities, including the banquet cost—and a including service as a Director. Being free T-shirt. Leaders will be encour- devoted to our mission—the study, aged to lead two trips. One leader per conservation, and enjoyment of Colo- trip may receive these benefits. rado’s birds—is what matters. 12. Convention Publicity and Advertising. Ted Floyd will coordi- Awards—Chris Owens discussed nate with Christian and Lisa. Larry recommendations, and the board dis- Modesitt will work with Western Field cussed potential awards.

Colorado Birds Spring 2016 Vol. 50 No. 2 67 CFO–Western Field Ornitholo- distributed some suggestions for im- gists (WFO) Partnership—Larry proving readability of the publication Modesitt discussed WFO’s 2016 Con- with some formatting changes. vention in Fortuna, California, 28 2. Membership—Lisa Edwards re- September to 2 October. Jon Dunn ported that we have grown to distrib- will be leading a pre-convention CFO uting 577 issues of Colorado Birds. Au- trip beginning 22 September to visit tomatic renewal is working well. several hotspots for California special- 3. CFO Field Trips—Doug Faulkner ties, including a pelagic trip. This trip mentioned a CFO trip in June. In ad- could be an opportunity for a swarm of dition, Mike Henwood will be leading lifers. Interested CFO members should two different trips for Sagebrush Spar- contact Larry Modesitt. row on 16 and 17 April. One will be along the Utah–Colorado line. Colorado Bird Records Commit- 4. COBBA II Marketing—Doug tee (CBRC)—Mark Peterson suggest- Faulkner. CFO has been posting on ed Bylaw changes regarding terms and Facebook and on our website. eBird submissions no longer will need 5. Compensation—Doug Faulkner. to be reviewed by CBRC, unless it is a We approved increased for layout of state review species. Colorado Birds from $250 to $325 per journal. The hourly rate for doing ad- CFO Website—David Gillilan ditional pages increases from $15 to asked for assistance in cropping pic- $25. This is expected to total $600 ex- tures. He noted that field trip reports tra per year, an amount that is in the now are posted on “Events & Field budget. Trips” on the “Welcome to CFO” tab. The next meeting will be at 11:00 Social Media Communications on 9 April 2016, in Grand Junction. —Christian Nunes reported more growth to 1,426 Facebook followers President Faulkner adjourned the and 300 on Twitter. meeting at 5:02 p.m.

Additional Committee Reports Respectfully submitted, 1. Colorado Birds—Scott Gillihan Larry Modesitt, Secretary

68 Colorado Birds Spring 2016 Vol. 50 No. 2 CFO Appreciation Award Given to Ranger Karl Manderbach

Joe Roller and Dave Leatherman

CFO’s mission is to study, conserve, and enjoy Colorado’s birds. The CFO Board periodically recognizes special individuals who contribute significantly to attaining that mission. In April 2015 we recognized Ranger Karl Manderbach of the City of Fort Collins Natural Areas Department with the coveted CFO Appreciation Award. Following the discovery by Fawn Simonds of a rare American Wood- cock (Scolopax minor) on 15 January 2015 at Bobcat Ridge Natural Area near Masonville in Larimer County, a pilgrimage of excited birders hurried there. Literally hundreds of timberdoo- dle enthusiasts trekked to Bobcat Ridge, a park not accustomed to that kind of attention, during the “shorebird’s” 12-day stay. With a couple of options as to how he could have reacted to the “happening,” resident ranger Karl Manderbach was positively over the top in his assistance American Woodcock, Bobcat Ridge to birders. Day after day he helped them Natural Area, Fort Collins, Larimer park safely along the muddy roads, ex- County. Photo by Glenn Walbek plained park regulations, and most of all helped spot the cryptic bird. (Where’s Waldo?) All the while he protected the woodcock and its habitat. Karl went from someone who didn’t know a woodcock from a windmill to THE expert on the Bobcat Ridge beauty. An untold number of avid birders saw their first American Woodcock in Colorado, and maybe anywhere, because of Karl’s shepherding. For that we thank him. On 22 January 2016 CFO member Dave Leatherman presented our plaque of appreciation to Ranger Karl at the Natural Areas Department’s annual Volunteer Appreciation Banquet. And then, woodcock redux! The next winter, during the 1 January 2016 Loveland Christmas Bird Count, David Wade discovered an Ameri- can Woodcock at the same site. Patiently, Karl again aided the gang of birders, one of whom, Cole Wild, found a second woodcock in the company of the first! Apparently Karl’s on-site hospitality extended to the bird itself, which returned a year later and even brought a friend. Congratulations to Karl Manderbach for earning the CFO Apprecia- tion Award.

Colorado Birds Spring 2016 Vol. 50 No. 2 69 John Kirk Townsend (1809–1851)

Bob Righter In 1833, John Kirk Townsend and Thomas Nuttall were the first naturalists to travel the Oregon Trail while assigned to the Nathan- iel J. Wyeth Second Expedition across the Rockies to the Pacific Ocean. The Oregon Trail, a 2,200-mile route originating in Indepen- dence, Missouri, traveled through the newly opened western lands, ending in Oregon. The trail was first trampled upon by fur trap- pers in 1811, and by the late 1830s large caravans of wagons began transporting vast numbers of pioneers to various westward destinations, some even going all the way to Oregon. Today Interstate 80 essentially fol- lows the original Oregon Trail. During the era very little was known about the natural history of the interior western United States. The Lewis and Clark Expedi- tion of 1804–1806 traveled a more northern route across the Great Plains, then up, over, and through the Rocky Mountains, finally John Kirk Townsend. Photogra- trekking their way along the Columbia River pher Unknown, Public Domain to the Pacific Ocean. Aside from just three new species of birds—Lewis’s Woodpecker, Clark’s Nutcracker, and Western Tanager, described by Alexander Wilson in 1811—no other new bird species were recognized. This is because the original, hand-written journals were lost and were only rediscovered in 1892 when Elliot Coues stumbled over a pile of old oilskins in the basement of the Academy of Natural Sciences and, eu- reka!, there were the original Lewis and Clark journals. But even after researchers burrowed through the journals, any potential new species lacked the definitive documentation for new species acceptance. The other organized expedition into the interior west was led by Major Steven Long, starting in1820, and had the dual purpose of gathering military information ands cataloging the natural history of the region. The expedition followed the Platte River drainage into territory now known as Colorado where they discovered many new species of plants, birds, and mammals. For a naturalist to be on an exploration of the interior western United States in the early 1800s, the result could be instant fame, similar perhaps to the first astronauts being launched into space—

70 Colorado Birds Spring 2016 Vol. 50 No. 2 everything they saw, touched and experienced was potentially new to science. When Nathaniel Wyeth was forming his second expedition to the Pacific, he invited the esteemed British botanist Thomas Nuttall to join his caravan. Nuttall, associated with the Academy of Natural Sciences of Philadelphia (ANSP), the leading natural history organization in the United States, invited a young, up-and-coming naturalist, John Kirk Townsend, to join him as the second naturalist, focusing on cataloging the birds and mammals. Townsend was born in Philadelphia in 1809. He attended the Westtown Boarding School near Philadelphia—probably the only school in the country offering courses in natural history. Other West- town graduates were Thomas Say, the distinguished naturalist special- izing in entomology and zoology, who was commemorated by having the Say’s Phoebe named in his honor, and John Cassin, the noted taxonomist at the ANSP, who was commemorated by the many birds named in his honor, such as Cassin’s Kingbird. Townsend was in the right place to acquire the skills for being a first-rate naturalist.

New Bird Species Discovered by Townsend while Traveling the Oregon Trail along the Great Plains and through Rocky Mountains Drainages (arranged by date of discovery) On 25 May 1834, when the expedition was within 25 miles of what is now Colorado’s northeast border, Townsend bagged what he thought was a new finch. The finch kept springing up from the prairie floor making beautiful warbling-gurgling–like sounds. The finch turned out to be what is now known as the Lark Bunting, the state bird of Colorado. Type specimen ANSP 2393. On 28 May 1834, 25 miles farther along the trail, Townsend bagged another new species, a male Chestnut-collared Longspur. Type specimen ANSP 24099. In early June 1834, while the expedition was near the Laramie Mountains in a territory now known as Wyoming, Townsend collected a group of little brown birds that were sent back to the ANSP. In 1856 John Cassin, the ornithologist at the Academy, while rifling through a collection of Clay-colored Sparrows, noticed Townsend’s specimens were different. Thus the Brewer’s Sparrow was officially introduced to science. Type specimen ANSP 24050. In mid-June, near South Pass, Wyoming, on the “table lands… near the last streams of the Platte…in the mountains in an area where not a single blade of grass for our horses,” Townsend collected the first Mountain Plover, type specimen ANSP 24353. Today, 181 years later, the Mountain Plover’s breeding habitat remains essentially unchanged.

Colorado Birds Spring 2016 Vol. 50 No. 2 71 In the middle of May, 1834, in sagebrush country, “west of South Pass betwixt the northern sources of the Platte and the Colorado…” (Green River), Townsend gathered another new species, the “Moun- tain Mocking-bird,” which today is known as the Sage Thrasher. Type specimen ANSP 23728. On 12 July 1834, near Ross’s Creek, Idaho, Townsend discovered an odd, long-tailed, finch-like bird attired in cryptic juvenile plumage. At a later date when Audubon was searching through Townsend’s western specimens, he noted the juvenile finch-like bird represented a new species, which he named the Green-tailed Towhee in his notes. It is of interest he didn’t illustrate the new species for his famous Birds of America, perhaps because the bird’s nondescript plumage could appear inappropriate for his forthcoming book, which depicted American birds in their finest attire, or he may have had doubts about the bird’s identity. Type specimen not exant. On 12 August 1834, while in the Sawtooth Mountains, Idaho, near the Snake River, Townsend collected a “Thrush” that he described as “…whitish below, with long rounded tail, every feather except the two middle ones largely tipped white…since the bird was molting, I foolishly threw it away….” Later on Audubon, using Townsend’s description, recklessly named this thrush species Townsend’s Mock- ing Thrush, based at the time on the flimsiest of evidence. Because Audubon was under time pressure from his printer to wrap things up as soon as possible this could be an explanation for his inappropriate ornithological behavior in regards to introducing the Townsend’s Solitaire to science. Type specimen not extant. Townsend sent many of his specimens on his western trip to the ANSP. Audubon was aware of this cache of new western species and in most situations he bought the excess specimens allocated to a particular species and used these as models for his Birds of America. In most situations he gave credit to Townsend for his discoveries, but not always.

New Bird Species Discovered by Townsend along the Columbia River Drainage (arranged in taxonomic order) Black Oystercatcher: Discovered sometime during 1836 by Dr. William Tolmie who gave the specimen to Townsend, who then forward it to the ANSP where Audubon described it and honored his friend John Bachman, instead of Townsend or Tomlie, with the specific epithetbachmanii . Type specimen not extant. Western Gull: On 6 October 1836, Townsend discovered what he believed to be a new species of gull at Cape Disappointment, Wash- ington, and shipped two specimens to ANSP where Audubon, with a

72 Colorado Birds Spring 2016 Vol. 50 No. 2 degree of doubt, described a new gull, the Western Gull. Type specimen unknown. Vaux’s Swift: Discovered and described by Townsend in 1839, Fort Van- couver, Washington. Townsend honored his friend William Vaux, a mineralogist who was associated with the ANSP. Type specimen ANSP 24169. Chestnut-backed Chickadee: Pos- sibly first discovered 12 May 1835, and described by Townsend in 1837, Fort Vancouver, Washington. Type specimen Oxford University Museum No. 11571. Swainson’s Thrush: Discovered by Townsend on the banks of the Colum- Townsend’s Solitaire, Chatfield State bia River near Fort Vancouver, Wash- Park, Douglas County, 3 January ington, 10 June, probably 1835. Nut- 2011. Photo by Loch Kilpatrick tall described the new thrush in 1840 and named it in honor of William Swainson for his early efforts in delineating this difficult group of thrushes from one another. Type specimen not exant. Bushtit: Discovered and described by Townsend in 1837, Fort Vancouver, Washington. Type specimen not extant. Black-throated Gray Warbler: Discovered and described by Townsend in 1837, Portland, Oregon. Type specimen United State Natural History Museum (USNM) No. 2918. Townsend’s Warbler: Discovered and described by Townsend in 1837, Fort Vancouver, Washington. Type specimen USNM No. 2918. MacGillivray’s Warbler: Townsend discovered and described this warbler in 1839 and named it after his friend William Tolmie: Tol- mie’s Warbler. When the type specimen arrived at the ANSP Audu- bon renamed the warbler after his close friend William MacGillivray, who worked closely with Audubon on his Ornithological Biographies. Publication was nearing the end and Audubon wanted to name a species in MacGillivray’s honor, even though it turned out to be at Townsend’s expense. Type specimen ANSP 23765.

New Species Discovered by Townsend on His Way to the Hawaiian Islands Black-footed Albatross: On Christmas Day, 1834, Townsend dis-

Colorado Birds Spring 2016 Vol. 50 No. 2 73 covered a new species while at sea. The specimen was forwarded to ANSP where Audubon described the bird after looking at other albatross species in the collections for comparison, then assigning the vernacular name Black-footed Al- batross. Type specimen does not appear extant. In December 1834 Nuttall and Townsend sailed for Hawaii for a three-month collecting trip. In November 1836 Townsend again sailed to Hawaii, then on to Ta- hiti, Valparaiso (Chile), and Ar- gentina, finally returning to Phila- delphia in November 1837. His field work greatly contributed to Townsend’s Warbler, Park County, 1 Sep- those countries’ knowledge about tember 2012. Photo by Peter Burke their bird life.

Townsend’s Place in History History has shown that being in the right place at the right time is a recipe for success, although history has also shown that it doesn’t always work out that way. Such was the case for Townsend. What he contributed to science on his westward trip should have securely placed him high on the list of the great naturalists of the early 19th century. Unfortunately for Townsend, the early 1800s is known in ornithological history as the Audubon era. Audubon’s accomplish- ments were legendary, and no one individual dominated ornithology during an era as Audubon did during his lifetime. Sadly, Townsend’s contributions drifted into obscurity. It may have been different if he had had the opportunity to describe and illustrate his newly discovered species, but the arrival on the scene of Audubon’s magnificentBirds of America sucked the air out of anyone else’s achievements and Townsend never fully received the recogni- tion he deserved.

Literature Cited Mearns, B., and R. Mearns. 2007. John Kirk Townsend. Barbara and Richard Mearns, Connanskowe, Kirkton, Dumfries, Scotland. Thwaites, R. G. 1905. Early Western Travels. Arthur H. Clarke Company, Cleveland, OH.

Robert Righter, Denver, Colorado, [email protected]

74 Colorado Birds Spring 2016 Vol. 50 No. 2 THE HUNGRY BIRD

Birds Exploring Defect as a Proven Foraging Strategy

Dave Leatherman As commonly used, the concept “normal” describes some thing or situation that is “good” or at least understood. “Back to normal” sounds comforting. I am sure folks living in Normal, Illinois, are proud of their hometown. When part of my job was helping diagnose tree pest issues for forest landowners, a concept that proved helpful at workshops was telling attendees to “learn what normal is.” It followed that if plant inspectors examined their valuable trees and shrubs in all seasons, stages, and ages, and thus thoroughly knew what normal or healthy looked like, they would better be able to detect the early onset of potential problems. As our doctors tell us, the earlier an issue is detected, the better the chances of curing it. Nip it in the bud. Birds clearly use this notion, or its opposite, “defect,” in detecting animal prey. Where something is absent, out of order, abnormal, or does not look right, the cause or maker of said variance from normal might be present nearby. Where there’s a broken window, there might be a burglar. Where you see crumbs, the Cookie Monster lurks. Origami is found in the artist’s shop. Dead leaves are red flags that just might lead under bark upstream to larvae with jaws or sucking mouthparts. If we birders learn to look at the world the way birds do, we will hopefully see more birds. At worst we will see interesting behaviors. The types of defect birds explore in their pursuit of prey are many. This article describes but a few of the common visual patterns I have observed Colorado birds keying in on while attempting to perform an activity that takes up about a third of their waking hours every single day of their lives—feeding themselves and their dependent offspring.

Missing Foliage or Holes in Foliage Leaves are centers of action in plants with chlorophyll, which is most of them. When combined with sunlight, water, and carbon di- oxide, chlorophyll enables the almost miraculous and Planet Earth– sustaining phenomenon of photosynthesis whereby plants manufac- ture their own food. The resultant sugar production by plants attracts consumption by many animals, foremost being invertebrates. Of course, insects form the bulk of backboneless animals that eat plants. The most straightforward insectivorous herbivory, simple chewing of holes in leaves, is carried out by forms with chewing mouthparts.

Colorado Birds Spring 2016 Vol. 50 No. 2 75 Included are larval and adult beetles, larval moths and butterflies, orthopterans (grasshoppers and their kin), mantids (praying mantids and walking sticks), and certain hymenopterans (bees, wasps, and ants). It seems easy to understand that birds would have learned by tri- al and error investigation of their world that, where leaves exhibit evidence of recent chewing by insects, the actual perpetrators of the damage might be present (Fig. 1). In a natural world ruled by sur- vival, repetitively successful trials morph into method. We have all seen tree-crown foragers like warblers, vireos, orioles, and chickadees tracking down larvae by first noticing holes.

Leaf Discoloration An entire leaf can be discolored (pale green, yellow, or ultimately brown) if it is nutrient deficient, dying, or dead. This is usually the result of an issue farther down the line in the branch to which it is attached, the trunk its branch grows from, the roots feeding the upper part of the plant, or even the soil. Whole leaves showing uniform discoloration are usually not caused by something directly feeding on them, and thus would not be all that productive for foraging birds looking for causal organisms. One key word in this description is “whole.” If, on the other hand, the discoloration is limited to parts of the leaf such that they form an irregular oval (called a blotch mine) or snakelike track (called a serpentine mine), then interest by birds is revived. Leafminers are highly evolved defoliators that have mastered the technique of feeding on leaves by getting between the upper and lower leaf surfaces and chewing in this unique, narrow space. The bodies of leafmining moths, flies, beetles, and wasps are quite dorso-ventrally compressed to fit their life style. Being a fairly big human, I remember times in crawl spaces when such a body would have been handy. I have seen birds consume blotch mining larvae in two ways. In the first they delicately peel off either the roof or floor of the tunneling larva’s comfort zone and extract it. In the second, especially used by big-billed birds like grosbeaks, they simply glom onto the entire discolored mine and enjoy a protein-spiked bit of salad. With serpentine miners, the method of removal is usually delicate extraction at the end of the path that is being elongated. Since the larva digging the tunnel is growing big- ger as it feeds, the most prudent end of the track for a bird to open is the widest end. The action end of the tunnel is also somewhat darker due to its greater accumulation of excrement pellets. Another exception to dead leaves usually not being all that productive as a site of exploration are dead leaf clusters. Little groups of

76 Colorado Birds Spring 2016 Vol. 50 No. 2 dead leaves might have been killed by lepidopteran larvae that tied them together with silk in the form of a shelter (see next section), or they might have been tied together after they died by a spider. Certain warblers like Worm- eating and Golden-winged are noted for their fondness for morsels found within dead leaf clusters (Fig. 2). Inhabitants of plant structures, like webbed-together leaves or galls, not involved in actively forming the structure, are called “inquilines.” These “squatters,” if you will, take advantage of a left-behind home and use it for their own purposes. Earwigs, aphids, spiders, lacewings and many other arthropods commonly live as inquilines. They benefit from the labor of Fig. 1. Brownheaded Ash Sawfly (To- other creatures but suffer at the beaks mostethus multicinctus) larvae and of their predators which care not who chewing damage to Green Ash (Fraxi- the building contractor was. nus pennsylvanica), Colorado Springs, As mentioned, whole brown CO. Photo by Dave Leatherman leaves, while usually not all that populated with prey themselves, can indicate issues upstream. Woodpeckers know well how to ex- ploit the larvae of bark and wood-boring beetles that divert water from distal parts of a tree, causing its leaves to discolor. It is rare, indeed, to see a Hairy or American Three- toed woodpecker in a tree that does not have Fig. 2. Warbling Vireo inspecting cluster of dead Russian- a crown red with a pre- olive leaves, probably for an “inquiline” species like an ponderance of dead earwig or spider. Lamar Community College Woods, La- needles. A mountain mar, Prowers County, Colorado on 12 September 2013. picid scans a conifer- Photo by Dave Leatherman

Colorado Birds Spring 2016 Vol. 50 No. 2 77 Figs. 3, 4, 5. Pine showing dead top (left), evidence of woodpecker predation on bark beetles in trunk of a pine with a dead top (middle) and bark flakes on ground under a bark beetle-infested pine with a dead crown after visitation by woodpeckers extracting beetle larvae (right). Photos by Dave Leatherman

ous hillside and goes to the pine, fir, or spruce with a discoloring or dead top (Fig. 3). A birder, likewise, looking for a year-list three-toed should key in on the red trees, too, and once found, search the branches and trunks to which those discolored needles are connected. In winter, think like a bird. Look for abnormal. While walking a trail or snowshoeing, notice the oddball trunk sur- rounded by snow littered with flakes of bark pulled off by woodpeckers digging down to phloem-feeding beetle larvae (Figs. 4 and 5), which they found from afar by noticing foliage that was not the normal green of surrounding conifers.

Origami Many leaf-feeding insects modify leaves by rolling, folding, or tying them into rather fancy, consistently patterned structures that potentially protect the makers from weather and detection by predators. Most of these are either lepidopteran larvae or spiders, and both utilize silk produced from mandibular glands or spinnerettes, respectively, to hold their creations in the desired po- sition. The idea is to fashion a protec- Fig. 6. Three styles of leaf modifica- tive structure and then engage a path to tion (aspen in this case) or “orgami”: adulthood by eating out of the structure. from l to r, rolling, folding, and ty- With the right search image, leaf rolls, ing, each the work of a different spe- folded leaves, and leaves tied together cies. Photo by Dave Leatherman

78 Colorado Birds Spring 2016 Vol. 50 No. 2 Figs. 7 & 8. Plains Cottonwood leaves at the LCC Woods in Lamar, CO tied together and somewhat discolored by subsequent feeding by a moth caterpillar within this structure (left). At right is an unidentified moth larva from tied aspen leaves (overtopping leaf has been removed) near Telluride, CO that is closely related to the unidentified larva found in the tied cottonwood leaves at left. The pale green areas in this photo show evidence of leaf grazing by the caterpillar and are the kind of abnormal discoloration birds key in on. Photos by Dave Leatherman

(Fig. 6), when arrayed against a background matrix of normal leaves, stand out. Once a bird finds one of these artsy meal packages, they handle it in ways similar to the ways they handle detected leafminers: probe for and pull out the inhabitant (Figs. 7 and 8), or if the structure is small, eat the whole thing. By far the most common method I have observed is beak probing followed by rather precise exorcism. Warblers and chickadees have mastered this.

Retained Bud Caps Tree buds are sheathed in a cap. In spring or early summer, as the new foliage of an impending growing season swells and elongates, the cap is loosened. Under the sheer force of meristematic cell division, it is shed. Free of this cap, the new blades or needles are free to unfurl and expand to full size. The caps of an individual tree, particularly those within one aspect of one tree, tend to pop off in syn- chrony. That is, the uniformity of light and temperature on one side of a crown tends to result in fairly uniform growth. The caps from neighboring branch ends tend to freefall within a day or two of one another. The timing or “phenology” of seasonal events like budbreak and autumn leaf drop can be quite exact in one tree, one clone (as in the case of color in aspen), or even one whole hillside. But if you ex- amine enough trees at the time the bud caps are being shed to make

Colorado Birds Spring 2016 Vol. 50 No. 2 79 room for the next set of pho- tosynthetic greenery, you will eventually see a cap here and there that did not get the memo. Often this is the result of insect mischief and is the sort of thing birds notice. During the Colorado Field Ornithologists’ Convention in Salida in May 2015, I was lucky enough to witness a great example of birds keying in on defect right in the parking lot of the motel next door. There, in a sea of asphalt and defying all that we are taught in botany class about the re- quirements for proper tree growth, was a rather mag- nificent Colorado blue spruce Fig. 9. Red Crossbill removing a retained bud cap towering perhaps 60 feet over prior to eating the larva feeding on foliage under- the cars. And in it were birds, neath. Photo by Dave Leatherman many birds. Mostly they were Red Crossbills and Pine Sis- kins. We know these birds to favor conifer seeds pulled from cones, but not on this day. Opportunistically, they were gorging on larvae of the western spruce budworm. Why the name “budworm”? Because after spending the winter as very tiny larvae within loose silken tents (“hibernacula”) attached to a small twigs, they come out of hiding in spring and tunnel into swell- ing buds. There they feed on nubile needles. Perhaps half the content of a bud, sometimes even more, is consumed before the needles therein even have a chance to practice their genetically programmed deal with the sun. Without a full complement of needles pushing outward, infested buds tend to blow their tops late, or not at all. What I quickly noticed with those voracious crossbills and siskins was a very certain orientation to a particular subset of new shoots. They were not at all interested in most pristine lime green puffs of soft new needles at branch ends. They were homing in on the ones with retained caps. A quick flick of the beak dislodged the papery cap (Fig. 9), revealing the fat, carmel brown budworm larva within. She/ He Scoooooorrrrres!!! (Figs. 10 and 11). And a “hat trick” only took two minutes.

80 Colorado Birds Spring 2016 Vol. 50 No. 2 Figs. 10 & 11. Red Crossbill (top) and Pine Siskin (bottom) feeding on Western Spruce Budworm larvae found under reddish- brown retained bud caps such as the three immedi- ately under the crossbill. Pristine new growth, such as appears in the far right of the crossbill photo was uninfested by budworms and went unsearched by the birds. Photos by Dave Leatherman

Frass This word is a polite way of saying “poop.” Insect excrement is a natural outcome of their feeding, and like holes, discoloration, origami, and many other versions of “defect,” can be used to detect the frasser (Figs. 12 and 13).

A Case of a Caterpillar Hiding Defect It Caused Remember those old TV Westerns where the stagecoach robbers would try

Fig. 12. A frass pellet at the rear of a Fig. 13. Tomato hornworm frass pellets tomato hornworm caterpillar. Photo by on the ground under an infested tomato David Shetlar, Ohio State University plant. Photo by David Shetlar, OSU

Colorado Birds Spring 2016 Vol. 50 No. 2 81 to hide their horses’ hoof prints from the posse by sweeping the trail clean with a tree branch? The American dagger moth (Acronicta americana) knew the trick centuries before the drama of the Wild West. The fuzzy yellow caterpillars with a few black tufts scallop big holes in maple leaves (Fig. 14). To hide this evidence that might Fig. 14. American Dagger Moth cat- be used by birds to find them, they clip erpillar on ground looking for pupation the petioles of fed-upon leaves, which site. Photo by Dave Leatherman then drop earthward (Fig. 15). Per- haps at some stage in the escalation of this predator–prey arms race, birds will spy partially chewed leaves with very short petioles littering the ground under infested maples and look up. Essentially, birds noticing defect in an effort to find what made the defect is a lot like what the human birders do who find all those wonderful species on the Rare Bird Alert. They know what normal looks like and try to find Waldo hiding in the mix. Many more examples exist besides what was covered above: specks on the glass of a still water surface; something that moves/falls in the “wrong” direction compared to the mostly ordered flow of leaves in a light breeze; a limp or weak Fig. 15. Silver maple leaves partially flutter amid the herd/flock; movement chewed and petiole clipped by American under the still grass; vibration beneath Dagger Moth caterpillar at left, intact leaf otherwise silent bark; the inattentive at right. Photo by Dave Leatherman back of a clueless finch bellied up with a flock of paranoid cohorts at a feeder; and so on. Bird like a hungry bird and my strong suspicion is you will sate your soul.

Acknowledgments I thank Whitney Cranshaw of Colorado State University for use of the two frass photos by David Shetlar of Ohio State University and for finding my photo of the clipped maple leaves in his files that could not be found in mine.

Dave Leatherman, [email protected]

82 Colorado Birds Spring 2016 Vol. 50 No. 2 Status of the Boreal Owl (Aegolius funereus) as a Breeding Species within Rocky Mountain National Park

Scott Rashid The Boreal Owl (Aeoglius funereus) has been documented as a nesting species throughout the higher mountains of Colorado (Palm- er and Ryder 1984). However, there has never been a nest of the species located within Rocky Mountain National Park (RMNP). In order to document nesting, without having located an active nest, we decided to set up mist nets to trap and band any young birds that we could capture. If we could capture a juvenile bird prior to it leaving its nesting area, within the boundaries of RMNP, we would demon- strate that the species does in fact nest within RMNP.

Boreal Owls in Colorado On 10 March 1996, I assisted Dr. Ron Ryder, professor emeritus from Colorado State University, with one of his road censuses along Cameron Pass, northwest of Fort Collins. This survey was to identify the number of vocalizing Boreal Owls present that particular evening. It was about 6:00 p.m. when we arrived at a small dot on the map called Gould, Colorado. The objective was to drive east to Chambers Lake over Cameron Pass (elevation 10,276 ft. [4318 m]), stopping every half mile to listen for calling owls. If none were heard, we would play a recorded Boreal Owl call and document what would transpire. That particular evening we heard nine different birds. One of the normal stops along the route was the Moose Visitor Center between Chambers Lake and Gould. We pulled into the parking lot, turned off the car, and stepped onto the pavement to hear a Boreal Owl vocalizing from within a spruce (Picea sp.) near the road just a few yards from us. Ron suggested that we stand at two different spots in the parking lot, which would enable us to triangulate on the calling bird. As we did this, Ron said, “Shine your light to where you think the bird is and I’ll shine mine to where I think the bird is.” As we shined our lights, a beautiful adult Boreal Owl was vocalizing, perched several meters up in the spruce. Prior to 1965 there were only four Boreal Owls documented in Colorado, with the first being obtained in 1896. Then in August 1963, Baldwin and Koplin (1966) collected a juvenile female on

Colorado Birds Spring 2016 Vol. 50 No. 2 83 Deadman Mountain in Larimer County. Throughout 16 years of roadside counts along Cameron Pass, Ron and his researchers found between zero and 27 calling owls each time the survey was taken. Dr. Ryder and Dave Palmer were instrumental in identifying and documenting the Boreal Owl as a nesting species in the lower 48 states (Palmer and Ryder 1984). Their first nest was found on 17 April 1981, along Cameron Pass. The owl’s nest was in a lodgepole pine (Pinus contorta) snag. That nest had failed, although the owls renested in that same cavity in 1982.

Hidden Valley Being a volunteer owl researcher for RMNP, on 31 March 1996, a few weeks after my Cameron Pass experience, I talked Jerry Zan- nineli, a birding friend of mine, into going to the Hidden Valley area of RMNP to search for Boreal Owls. Hidden Valley was a downhill ski area that is no longer in use. The unused ski runs are still visible and are most likely used by the Boreal Owls for hunting small ground-dwelling mammals as well as the medium-sized birds that in- habit the area. I chose to search Hidden Valley in RMNP because it looks very similar to the area along Cameron Pass that Ron and I had surveyed a few weeks earlier. Both habitats consist primarily of Douglas fir (Pseudotsuga menziesii) and Engelmann spruce (Picea engelmannii), and have openings in the forests as well as active water sources. This combination is what Boreal Owls seem to prefer for nesting. We arrived at Hidden Valley at 8:15 p.m. and began walking up one of the unused ski runs. At this point the full moon was rising over the mountain and was so bright that our flashlights were no longer needed. As we hiked, we heard the familiar winnowing of the male Bo- real Owl. As the owl was calling we walked toward it, knowing that while the owl was calling it could not hear us. When the owl stopped calling, I mimicked its call a few times, then stopped and listened. A short time later the owl began vocalizing again. This time it had moved closer to us. As before, while the owl was calling we walked toward it. At this point, we were just a few hundred meters from the bird. I began mimicking the call softer and softer until the owl was just about a meter from us. Due to the light of the moon, we could plainly see the owl as it perched near us at eye level. Knowing that North- ern Saw-whet Owls (Aegolius acadicus) can be closely approached, I reached out to see if I could touch the owl, but it flew off. Virtually every year since that first sighting in RMNP, I have either

84 Colorado Birds Spring 2016 Vol. 50 No. 2 seen or heard Boreal Owls at Hidden Valley. However, I have yet to either locate a Boreal Owl nest or hear more than a single bird calling at any given time. Therefore, to verify whether or not Boreal Owls nest within the boundaries of RMNP, I decided to set up a se- ries of mist nets to trap and band the owl(s) at Hidden Valley. In do- Fig. 1. Adult Boreal Owl perched near the mist nets ing this my theory was prior to being captured. Photo by Scott Rashid that if I were to capture a juvenile Boreal Owl within the boundaries of the Park, prior to it leaving the area where it had hatched, it would verify that Boreal Owls do in fact nest within RMNP. I spoke with Greg Hayward (a Boreal Owl researcher now living in Alaska) and Ron Ryder; both told me that, in their opinions, if I were to capture a juvenile Boreal Owl in September in Hidden Valley inside RMNP, the captured owl would have to have hatched within the boundaries of RMNP. Apparently juvenile Boreal Owls do not disperse from their natal grounds until later in the year, possibly the third or fourth weeks in October or even later.

Fig. 2. The wing of a Hatching Year (HY) Fig. 3. An adult Boreal Owl. This Boreal Owl. Note all feathers are the same bird is considered After Second tone. Photo by Roy Powel Year (ASY). Each feather is labeled N=new, O=old, VO=very old. Pho- to by Scott Rashid

Colorado Birds Spring 2016 Vol. 50 No. 2 85 Banding Boreal Owls On 3 October 2011, Gary C. Miller (wildlife biologist for RMNP), Apryle Craig (RMNP research assistant), and I placed three 2.6-meter–high and 12-meter–long mist nets in the spruce-fir forest behind the visitor’s center at Hidden Valley. The three nets were placed in a “U” shape. In the center of that “U” was a CD player with detachable speakers. The speakers were placed as far apart as the wires would allow. Both speakers were placed on plastic milk crates. One speaker faced northwest and the other southeast. The reason the speakers are placed in this manner is to make it harder for the owls to determine the exact source of the sound. At 7:30 p.m. we broadcast the territorial call of a male Boreal Owl. We stationed ourselves in the visitor’s center between net checks. The nets were checked every half hour by walking the edge of each net and shining a flashlight on the net in front of us to determine if an owl was captured (Fig. 1). While we were broadcasting the Boreal Owl call, we could hear Northern Saw-whet Owls calling in the distance, seemingly agitated by the call of the larger Boreal Owl. At 9:40 p.m., our first Boreal Owl was found entangled in one of the mist nets. Using Pyle’s (1997) identification guide, we determined that the owl had hatched that same year, making it a juvenile Boreal Owl (Fig. 2). The bird had a wing length of 172 mm, a tail length of 103 mm, and it weighed 133.6 grams. Based on the Pyle guide, the owl was determined to be a juvenile female. The owl was banded with a U.S. Fish and Wildlife Service size 6 leg band, number 1156-02338. This was the first-ever documented juvenile Boreal Owl within RMNP. To release the owl it was simply placed in a live spruce tree. Soon after it was put on the branch, the bird flew off into the darkness. A week later, on 10 October, we returned with the intention of trapping more Boreal Owls, and possibly the Northern Saw-whet Owls as well. We decided to begin that trapping session by broadcasting the territorial call of the Northern Saw-whet Owl. As before, the call of the owl was broadcast at 7:30 p.m. At the 8:00 p.m. net check we found a second-year Northern Saw-whet Owl entangled in one of the mist nets. Again using Pyle’s guide, we determined that bird to be a second-year female. It had a wing length of 148 mm, a tail length of 69 mm and weighed 93.8 grams. I placed a size four–short leg band, number 1014-28541, on that bird. After the Northern Saw-whet Owl was captured, we began broadcasting the call of the Boreal Owl. At the 9:30 p.m. net check we found two Boreal Owls entangled in two different nets. Both birds were females. One owl had a wing length of 183 mm, tail length of

86 Colorado Birds Spring 2016 Vol. 50 No. 2 100 mm, and weighed 130.1 grams. That bird was determined to be an ASY owl, i.e., it was more than two years old (Fig. 3). The second owl was determined to have hatched the same year we had caught it. It had a wing length of 185 mm, tail length of 105 mm, and weighed 125.4 grams. I placed band number 1156-02339 on the first Boreal Owl captured that evening and band number 1156-02340 on the second owl. We took the birds out of the visitor’s center and placed them in different spruce trees for release. Even though no one has yet found a Boreal Owl nest within RMNP, our capture of two juvenile, young-of-the-year birds demonstrates that the species does indeed nest in the park.

Acknowledgments I would like to thank Jeff Conner, Apryle Craig, Gary C. Miller, Ronald Ryder, Jerry Zaninnelli, and RMNP.

Literature Cited Baldwin, P. H., and J. R. Koplin. 1966. The Boreal Owl as a Pleistocene relict in Colo- rado. The Condor 68:299–300. Palmer, D. A., and R. A. Ryder. 1984. The first documented breeding of the Boreal Owl in Colorado. The Condor 86:241–217. Pyle, P. 1997. Identification Guide to North American Birds Part 1. Slate Creek Press, Point Reyes Station, CA. Rashid. S. 2009. Small Mountain Owls. Schiffer Publishing, Atglen, PA. pp. 154–169.

Scott Rashid, [email protected]

Colorado Birds Spring 2016 Vol. 50 No. 2 87 NEWS FROM THE FIELD

Fall 2015 (August–November)

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 In contrast to the extreme weather of fall 2013 and 2014, tranquil weather was typical for Colorado birding in fall 2015. September was a particularly dry and calm month statewide. The fall 2015 passer- ine migration seemed to have more of a “western” flavor than usual. For example, Cassin’s Vireos were found in unusually high numbers statewide. Type 3 (Western Hemlock) Red Crossbills, found primarily in coastal areas of Washington and British Columbia but irruptive elsewhere, were documented in two locations in northeast Colorado. Colorado birders noted that eastern warblers were generally scarce during their fall outings. During the months of August to Novem- ber 2015, 32 different warbler species were reported across the state, compared to 38 species during spring 2015. For the second year in a row, lake levels remained high through the fall. As a result, mudflats attractive to shorebirds were in short supply. Although fall 2015 won’t be remembered for abundant shorebirds and eastern warblers, it will be remembered for a great diversity of rare birds. The sightings below include a remarkable 25 different species on the state review list. Three species had not been seen in the state in several years, including Cerulean Warbler (previous accepted record in 2005), Red-shouldered Hawk (previous accepted record in 2010) and Inca Dove (previous accepted record in 2012). Fall 2015 was productive for rare herons, with Tricolored Heron, Yellow- crowned Night-Heron and Least Bittern all seen in the state. In the mountains and west, birders found numerous species not normally seen there, including Greater White-fronted Goose, Snow Goose, Broad-winged Hawk, Common Tern, Vermilion Flycatcher, Brown Thrasher, Worm-eating Warbler, Hooded Warbler, Swamp Sparrow, and Painted Bunting.

88 Colorado Birds Spring 2016 Vol. 50 No. 2 In the list of reports below, county names are italicized, and the following abbreviations are used: CFO – Colorado Field Ornithologists; CG – campground; m.ob. – many observers; NA – Natural Area; NHS – National Historic Site; NP – National Park; NWR – Na- tional Wildlife Refuge; Res. – Reservoir; SP – State Park; STL – State Trust Lands; SWA – State Wildlife Area.

Greater White-fronted Goose: fat, 24–25 Nov (Dona Hilkey, Mi- 1 at DeWeese Res., Custer, 22 Sep chael Mack). 1 at Lon Hagler Res. (Rich Miller); rare at high-elevation SWA and Boedecker Res., Larimer, lakes in Colorado. Other reports from 27–29 Nov (Nick Komar, m.ob.). Adams, Arapahoe, Boulder, Denver, 5 at Highline Lake SP, Mesa, 28–29 Douglas, El Paso, Huerfano, Jefferson, Nov (Ronda Woodward, Eileen Cun- Kiowa, Logan, Sedgwick, and Weld, 31 ningham, Ron Lambeth, Denise and Aug–30 Nov. Mark Vollmar, Mike Henwood, Nic Snow Goose: 2 in Craig, Moffat, Korte). 1 at Lake Granby, Grand, 30 30 Oct (Forrest Luke); rare in north- Nov (Carol Hunter). west Colorado. Tundra Swan: Reports from BRANT (Black): 1 at Lake Beck- Arapahoe, Bent, Boulder (as many as with, Pueblo, 27 Nov (David Silver- 14), Douglas (as many as 19), El Paso, man). Garfield, Jefferson, Larimer, Mesa, Trumpeter Swan: 8 at Horse- Moffat (as many as 13), and Routt, 24 tooth Res., Larimer, 22 Nov (Jeffrey Oct–30 Nov. Birek). 4 at Browns Park NWR, Mof- Mallard (Mexican): 2 at Stewarts’

White-tailed Ptarmigan, Guanella Pass, Pacific Loon, Terry Lake, Boulder Clear Creek County, 24 November County, 25 November 2015. Photo by 2015. Photo by Mark Chavez David Waltman

Colorado Birds Spring 2016 Vol. 50 No. 2 89 Least Bittern, Bent CR JJ, Bent County, Cooper’s Hawk, Longmont, Boulder 21 November 2015. Photo by Janeal County, 8 August 2015. Photo by Thompson Todd Deininger

Pond, Weld, 2 Nov (Steven Mlodi- Riffe, m.ob.). 1 at Big Johnson Res., now, Kathy Mihm Dunning). El Paso, 29 Oct (John Drummond, American Black Duck x Mallard Glenn Walbek). 2 at Cherry Creek (hybrid): 1 at Riverbend Ponds NA, SP, Arapahoe, 8–16 Nov (Chris Ru- Larimer, 24 Oct (Nick Komar). rik, m.ob.). 1 at Jumbo Res., Logan, Surf Scoter: Reports from Arapa- 22 Nov (David Dowell, Joey Kellner, hoe, Grand, Jefferson, La Plata, Lar- Kathy Mihm Dunning, Dick Schot- imer, Mesa, Montrose, Park, Pueblo, tler). 1 at Pueblo Res., Pueblo, 25 Nov San Miguel, and Weld, 8 Sep–30 Nov. (Brandon Percival, Chris Knight). White-winged Scoter: 1 at Cherry Long-tailed Duck: 1 at Lake Ch- Creek SP, Arapahoe, 18 Oct (Gene eraw, Otero, 8 Nov (Mark Peterson). Rutherford). 2 at South Platte Res., 1 at North Sterling Res., Logan, 29 Arapahoe, 8 Nov (Brian Johnson). 1 at Nov (Kathy Mihm Dunning, Joey Aurora Res., Arapahoe, 14 Nov (Scott Kellner). 1 at Jumbo Res., Sedgwick, Manwaring). 1 at North Sterling Res., 29 Nov (Joey Kellner, Kathy Mihm Logan, 22 Nov (Joey Kellner, Kathy Dunning). Mihm Dunning, David Dowell, Dick Common Goldeneye: 1 immature Schottler). 2 at Rawhide Energy Sta- at Prewitt Res., Washington, 12 Aug–3 tion/Hamilton Res., Larimer, 23 Nov Oct (David Dowell, Norm Lewis, Wil- (Janice Backstrom). 1 at Baseline liam Kaempfer); rare in Colorado in Res., Boulder, 28–29 Nov (Peter Gent, summer, particularly on the plains. m.ob.). Common Merganser: 12,000 at Black Scoter: 1 at Spinney Moun- Windsor Res., Weld, 29 Nov (Steven tain Res., Park, 25 Oct–1 Nov (Sue Mlodinow, David Dowell).

90 Colorado Birds Spring 2016 Vol. 50 No. 2 Solitary Sandpipers, Lamar, Prowers Ruddy Turnstone, Chatfield State Park, County, 22 August 2015. Photo by Ja- Jefferson County, 10 October 2015. neal Thompson Photo by Mark Chavez

Red-throated Loon: 1 juvenile at Dunning, Norman Erthal, Joey Kell- Terry Lake, Boulder, 25 Oct–7 Nov ner). 1 juvenile at Sixmile Res., Boul- (David Dowell, John Vanderpoel, der, 27–28 Nov (William Kaempfer, m.ob.). 1 juvenile at Cherry Creek m.ob.). SP, Arapahoe, 21 Nov (Glenn Wal- Red-necked Grebe: Long-staying bek, Gene Rutherford). 1 immature birds at Chatfield SP,Douglas/Jef - at Union Res., Weld, 25 Nov (Steven ferson, with 1 seen initially on 4 Oct Mlodinow). 1 at Prewitt Res., Logan, (Van Remsen), joined by others in 29 Nov (Joey Kellner, Kathy Mihm Nov when as many as 4 were seen on Dunning). 14 Nov (Glenn Walbek), and then 2 Pacific Loon: 1 adult at Cherry continuing until 28 Nov (m.ob.). 2 at Creek SP, Arapahoe, 25 Oct–30 Nov Catamount Lake, Routt, 5 Oct (Tresa (Kay Rasmussen, m.ob.). 1 at Lake Moulton). 1 at Jackson Res., Morgan, Trinidad, Las Animas, 1 Nov (Rich 12 Oct (David Dowell). 1 and then 2 Miller). 1 at Marston Res., Denver, 2 at Union Res., Weld, 14 Oct–11 Nov Nov (Alec Hopping). 1 at Ridgway (Steven Mlodinow, Carl Bendorf, Res., Ouray, 9–10 Nov (Kent Nel- Mark Duchesne). 1 at Lake Loveland, son, Brenda Wright, Coen Dexter). 1 Larimer, 15 Oct (Irene Fortune). 1 at at Lower Latham Res., Weld, 13 Nov Big Johnson Res., El Paso, 17 Oct–22 (Steven Mlodinow). 1 at Jackson Nov (Aaron Driscoll, m.ob.). 1 at Res., Morgan, 14–19 Nov (Boulder Cherry Creek SP, Arapahoe, 1–17 Nov Bird Club, m.ob.). 1 at Timnath Res., (Gwen Moore). 1 on 11 Nov and then Larimer, 22 Nov (Brandon Nooner). 2 on 25 Nov at Pueblo Res., Pueblo, 1 adult at Terry Lake, Boulder, 24–25 25 Nov (Brandon K. Percival, Chris Nov (David Dowell, m.ob.). 1 at Knight). 1 at Gateway Park Pond near Chatfield SP,Douglas/Jefferson , 24 Fort Collins, Larimer, 14 Nov (Robert Nov (Glenn Walbek, Kathy Mihm Beauchamp). 1 at Clement Park and

Colorado Birds Spring 2016 Vol. 50 No. 2 91 Tricolored Heron, Cottonwood Marsh, Yellow-crowned Night-Heron, Wheat Boulder County, 10 November 2015. Ridge Greenbelt, Jefferson County, 8 Photo by David Waltman August 2015. Photo by Mark Chavez

Buff-breasted Sandpiper, Ramah Reser- Inca Dove, Private Residence, El Paso voir, El Paso County, 22 August 2015. County, 19 November 2015. Photo by Photo by Bill Maynard Mark Chavez

92 Colorado Birds Spring 2016 Vol. 50 No. 2 Rufous Hummingbird, Private Resi- dence, Larimer County, 13 August Northern Flicker, Crow Valley Camp- 2015. Photo by Dave Leatherman ground, Weld County, 8 November 2015. Photo by Mark Chavez

Loggerhead Shrike, juvenile, Larimer CR 5 north of Buckey Rd, Larimer County, 4 August 2015. Photo by Dave Leatherman

Tennessee Warbler, Colorado State University Campus, Larimer County, 24 November 2015. Photo by Mark Chavez

White-eyed Vireo, Crow Valley Camp- ground, Weld County, 8 November 2015. Photo by Mark Chavez

Colorado Birds Spring 2016 Vol. 50 No. 2 93 Short-billed Dowitcher, Chatfield State Wilson’s Snipe, Upper Queens Reser- Park, Jefferson County, 25 August voir, Kiowa County, 1 September 2015. 2015. Photo by Mark Chavez Photo by Janeal Thompson

Johnson Res. near Littleton, Jefferson, from Boulder, El Paso, Logan, Morgan, 25 Nov (C Warneke). Otero, and Weld, 30 Sep–13 Nov. LEAST BITTERN: 1 near John American Golden-Plover: 3 at Martin Res., Bent, 20–21 Nov (Duane Timnath Reservoir, Larimer, 12–24 Nelson, m.ob.). Sep (group led by Nick Komar, TRICOLORED HERON: 1 im- m.ob.). 1 at Jumbo Res., Logan, 27 mature at Walden Ponds, Boulder, 11 Sep (Steve Larson, Glenn Walbek). Oct (Jamie Simo, Maikel Wise, Susan 1 northwest of Snyder, Morgan, 30 W, Peter Gent, m.ob.). Sep–3 Oct (Steven Mlodinow, Dean YELLOW-CROWNED NIGHT- Shoup, m.ob.). HERON: 1 adult at Wheat Ridge Whimbrel: 1 at Windsor Res., Greenbelt, Jefferson, 6–11 Aug (Ben- Weld, 28 Sep (Steven Mlodinow). jamin Peter, m.ob.). Ruddy Turnstone: 1 at Chatfield RED-SHOULDERED HAWK: 1 SP, Douglas, 6–10 Oct (Michael Kies- immature at North Sterling Res., Lo- sig, m.ob.). gan, 30 Aug–6 Sep (group led by Wil- Dunlin: 1 at Windsor Res., Weld, liam Kaempfer, m.ob.). 14 Oct (Steven Mlodinow). 1 at Tim- Broad-winged Hawk: 7 at Flagler nath Res., Larimer, 25 Oct–24 Nov Res. SWA, Kit Carson, 30 Sep (Glenn (Andy Bankert, m.ob.). 1 at Vega Res. Walbek). 1 at Cottonwood Pass, Mon- and SP, Mesa, 30 Oct (JoAnn Riggle). trose, 28 Sep and 1 at Nucla, Montrose, 2 at Lake Loveland, Larimer, 29 Nov– 1 Oct (Brenda Wright, Coen Dexter); 11 Dec (Irene Fortune, m.ob.). rare in western Colorado. Other re- Buff-breasted Sandpiper: 1 at Ra- ports from Arapahoe, Bent, Kit Car- mah Res. SWA, El Paso, 21–22 Aug son, Larimer, Logan, Morgan, Prowers, (Gary Koehn, George Cresswell, Washington, and Weld, 13 Sep–12 Oct. m.ob.). 1 at North Sterling Res., Lo- Black-bellied Plover: Reports gan, 9 Sep (Mark Holmgren).

94 Colorado Birds Spring 2016 Vol. 50 No. 2 Sabine’s Gull, Big Johnson Reservoir, El Arctic Tern, Chatfield State Park, Jeffer- Paso County 5 September 2015. Photo son County, 7 October 2015. Photo by by Bill Maynard Mark Chavez

Short-billed Dowitcher: 1 at Jaeger sp.: 1 at Union Res., Weld, Chatfield SP, Jefferson, 24–29 Aug 13 Oct (Steven Mlodinow). (Alec Hopping, m.ob.). 1 northwest LITTLE GULL: 1 at Horseshoe of Cheyenne Wells, Cheyenne, 8 Sep Res., Larimer, 3 Oct (Nick Komar, (Alec Hopping). 1 at Upper Queens/ Austin Hess, David Wade). Neeskah Res., Kiowa, 10 Oct (Chris Laughing Gull: 1 immature at Rurik, David Dowell). Pueblo Res., Pueblo, 18 Sep (Brandon AMERICAN WOODCOCK: 1 K. Percival). at Colorado State Univ., Larimer, 21 Laughing x Ring-billed Gull (hy- Nov (John Shenot, Joe Mammoser, brid): 1 at Terry Lake, Boulder, 25 Nov Andy Bankert, Dave Leatherman, (David Dowell, Steven Mlodinow). Austin Hess). Mew Gull: 1 juvenile at Union Red Phalarope: 1 at Chatfield SP, Res., Weld, 14 Oct (Steven Mlodi- Douglas, 18–21 Sep (Doug Kibbe, now). 1 juvenile at Aurora Res., m.ob.). 1 at Spinney Mountain Res., Arapahoe, 12–27 Nov (David Dowell, Park, 22 Sep (David Suddjian). Sin- Gene Rutherford). 1 adult at Cher- gles at Jumbo Res., Logan, 3 Oct (Da- ry Creek SP, Arapahoe, 21–28 Nov vid Dowell) and 25 Oct (Kathy Mihm (Glenn Walbek, m.ob.). Dunning, Joey Kellner). 1 at Prince California Gull: 5,250 at Windsor Lake #2, Boulder, 22 Oct (Chris Ru- Res., Weld, 29 Nov (Steven Mlodi- rik, m.ob.). now, David Dowell). PARASITIC JAEGER: 1 juve- Herring Gull: 1,225 at Windsor nile at Pueblo Res., Pueblo, 18 Sep Res., Weld, 29 Nov (Steven Mlodi- (Brandon K. Percival). 1 juvenile at now, David Dowell). Jackson Res., Morgan, 3 Oct (Chris Herring x Glaucous-winged Gull Wood, Jessie Barry). 1 adult at Jackson (hybrid): 1 adult at Aurora Res., Res., Morgan, 4–7 Oct (Kathy Mihm Arapahoe, 12 Nov (David Dowell). Dunning, Norman Erthal, m.ob.). Great Black-backed Gull: 1

Colorado Birds Spring 2016 Vol. 50 No. 2 95 Caspian Tern, Jumbo Reservoir, Logan County, 1 August 2015. Photo by Kathy Mihm Dunning adult female, returning for the 22nd Springs, El Paso, 15–22 Nov (Sharon consecutive winter, at Pueblo Res., Milito, m.ob.). Pueblo, 23 Nov continuing into win- Boreal Owl: Reports from Chaffee, ter (Stephany McNew, Brandon K. Eagle, Gunnison, Jackson, and Summit, Percival, m.ob.). 6 Sep–9 Nov. Caspian Tern: Reports from Boul- RUBY-THROATED HUM- der, Douglas, El Paso, Jefferson, Logan, MINGBIRD: 1 in Fort Collins, Lar- Pueblo, Sedgwick and Weld, 1 Aug–7 imer, 15 Aug (Ken Pals). 1 in Lamar, Oct. Prowers, 9 Sep (Dorothy Russell). Common Tern: 1 at Vega Res., COSTA’S HUMMINGBIRD: Mesa, 7 Sep (Nic Korte). 1 at High- 1 female type in Rye, Pueblo, 20 Sep line Res., Mesa, 15 Sep (Denise & (David Silverman). Mark Vollmar). 3 at Ruedi Res., Eagle/ ACORN WOODPECKER: 1 in Pitkin, 21 Oct (Tom & Kay McCon- Indian Hills, Jefferson, 2–3 Sep (Peggy nell); rare in western Colorado. Corpenny, m.ob.). Other reports of ARCTIC TERN: 1 juvenile at ongoing birds in Durango (La Plata) Chatfield SP,Douglas/ Jefferson, 2–7 and Pueblo Mountain Park (Pueblo). Oct (Glenn Walbek, m.ob.). 1 juve- Yellow-bellied Sapsucker: Reports nile at Boulder Res., Boulder, 11 Nov from Bent, Denver, El Paso, Jefferson, (Peter Burke, m.ob.). Kit Carson, Las Animas, Morgan, INCA DOVE: 1 in Colorado Prowers, and Yuma, 5 Oct–22 Nov.

96 Colorado Birds Spring 2016 Vol. 50 No. 2 Common Poorwill, Cheeseman Park, Broad-tailed Hummingbird, Xeriscape Denver County, 3 October 2015. Pho- Garden, El Paso County 4 September to by Mark Chavez 2015. Photo by Bill Maynard

EASTERN WOOD-PEWEE: 1 Miguel, Washington, Weld, and Yuma, at Tamarack Ranch SWA, Logan, 19 16 Aug–17 Oct. Jul–6 Aug (David Dowell, Chris Ru- Blue-headed Vireo: 1 in Ovid, rik, Steven Mlodinow). 5 at Sandy Sedgwick, 5 Sep (David Dowell). 1 in Bluffs STL, Yuma, 7 Sep (David Dow- Lamar, Prowers, 9 Oct (Janeal Thomp- ell). 1 at Crow Valley CG, Weld, 9 Sep son). 1 at Two Buttes SWA, Baca, 10 (Dave Leatherman). 1 in Fort Collins, Oct (David Dowell, Chris Rurik). 1 in Larimer, 3 Oct (Nick Komar). Arriba, Lincoln, 17 Oct (Kathy Mihm YELLOW-BELLIED FLYCATCH- Dunning, Joey Kellner). 1 at Flagler ER: 1 at Fox Ranch, Yuma, 9 Oct Res. SWA, Kit Carson, 17–24 Oct (Glenn Walbek, Joey Kellner, Steven (Joey Kellner, Kathy Mihm Dunning, Mlodinow, Kathy Mihm Dunning). Scott Manwaring). 1 at Fairmount Vermilion Flycatcher: 1 adult fe- Cemetery, Prowers, 19 Oct (Dave male in Grand Junction, Mesa, 13 Sep Leatherman). (Ron Lambeth). Philadelphia Vireo: 1 at Tamarack White-eyed Vireo: 1 at Stalker Ranch SWA, Logan, 29 Aug (group Lake, Yuma, 9 Sep (Nick Moore, Ste- led by William Kaempfer). 1 northeast ven Mlodinow). 1 at Crow Valley CG, of Deer Trail, Arapahoe, 7 Sep (Gene Weld, 8 Nov (Mark Chavez). Rutherford). 1 at Flagler Res. SWA, Cassin’s Vireo: 11 at Flagler Res. Kit Carson, 20 Sep (Chris Goulart). SWA, Kit Carson, 6 Sep (Chris Ru- 1 at Denver Botanic Gardens and rik, David Dowell). Other reports Cheesman Park, Denver, 23–28 Sep from Adams, Arapahoe, Baca, Boulder, (Jared Del Rosso, Chris Rurik). Cheyenne, Conejos, Custer, Douglas, Blue Jay: 158 at Clear Spring El Paso, Elbert, Fremont, Grand, Jef- Ranch near Fountain, El Paso, 4 Oct ferson, Kiowa, Kit Carson, Larimer, (Gloria Nikolai). Lincoln, Mesa, Moffat, Morgan, Phil- Winter Wren: Reports from Arap- lips, Pitkin, Prowers, Pueblo, Routt, San ahoe, Baca, Bent, El Paso, Kit Carson,

Colorado Birds Spring 2016 Vol. 50 No. 2 97 Red-headed Woodpecker, Riverside Red-bellied Woodpecker, Crow Valley Cemetery, Prowers County, 8 August Campground, Weld County, 8 Novem- 2015. Photo by Janeal Thompson ber 2015. Photo by Mark Chavez

Lincoln, Morgan, and Pueblo, 11 Oct– high-elevation sightings in Rocky 30 Nov. Mountain NP, Larimer, 16 Oct (Oliver SEDGE WREN: 1 at Sand Creek Komar) and near Central City, Gilpin, Massacre NHS, Kiowa, 26 Sep (Wil- 30 Oct (Doug Kibbe). liam Kaempfer). 1 at Union Res., Sprague’s Pipit: As many as 6 at Weld, 21 Oct (Steven Mlodinow). “Pipit Hill” near Hale, Yuma, 3–17 Carolina Wren: 1 in Wetmore, Oct (m.ob.). 2 at Fox Ranch, Yuma, Custer, 20 Aug (Alec Hopping). 1 9 Oct (Glenn Walbek, Steven Mlodi- at Sombrero Marsh, Boulder, 14 Nov now, Kathy Mihm Dunning). 5 at (group led by Steve Frye). Chico Basin Ranch, El Paso, 15–20 Varied Thrush: 1 at Stulp Ranch Oct (m.ob.). near Lamar, Prowers, 15–20 Oct (Jane Chestnut-collared Longspur: 2,200 Stulp, Janeal Thompson, Dorothy in Weld north of Jackson Res., 30 Sep Russell). 1 at Chico Basin Ranch, (Steven Mlodinow, Dean Shoup). El Paso, 14 Nov (Aaron Shipe). 1 Worm-eating Warbler: 1 at Chat- at Fountain Creek Regional Park, El field SP,Douglas , 12 Sep (group led by Paso, 29 Nov (David Chartier, Bill Joey Kellner). 1 in Steamboat Springs, Maynard). 1 in Granby, Grand, 29 Routt, 21 Sep (Thomas Litteral). Nov continuing into winter (Cathy Northern Waterthrush: Re- Craig, m.ob.). ports from Arapahoe, Baca, Boulder, Brown Thrasher: 1 near Guanella Custer, El Paso, Elbert, Huerfano, Pass, Clear Creek, 8 Oct (Steve Lar- Larimer, Lincoln, Moffat, Prowers, son, Van Remsen); unusual for such Pueblo, Washington, and Weld, 7 high elevation (10,725 feet). Other Aug–5 Oct.

98 Colorado Birds Spring 2016 Vol. 50 No. 2 Red-naped Sapsucker, Crow Valley Merlin, Stulp Farmyard, Prowers Coun- Campground, Weld County, 26 Septem- ty, 15 October 2015. Photo by Janeal ber 2015. Photo by Todd Deininger Thompson

Blue-winged Warbler: 1 at Welches- Arapahoe, Boulder, Douglas, El Paso, ter Tree Grant Park, Jefferson, 23 Aug Jefferson, Kit Carson, Mesa, Morgan, (Gerald Baines). Pueblo, Washington, Weld, and Yuma, Black-and-white Warbler: 1 at 23 Aug–24 Oct. Beaver Brook Res. 3A northwest of Nashville Warbler: Reports from Evergreen, Clear Creek, 18 Aug (Doug Adams, Arapahoe, Baca, Chaffee, Kibbe, Mackenzie Goldthwait). 3 Denver, El Paso, Elbert, Jefferson, Kit near Eads, Kiowa, 30 Aug (Alec Hop- Carson, Logan, Moffat, Montezuma, ping, Steven Mlodinow). 1 at Crow Morgan, Prowers, Pueblo, Routt, and Valley CG, Weld, 5–13 Sep (Austin Washington, 3 Aug–21 Oct. Hess, Susan Bonfiglio, Matt Clark, MOURNING WARBLER: 1 at Karen Goetz, Steven Mlodinow, Sean Flagler Res. SWA, Kit Carson, 28 Aug Walters). 1 at Brett Gray Ranch, Lin- (Alec Hopping). coln, 11 Sep (Kathy Mihm Dunning, Hooded Warbler: 1 at Ridgway SP, Mark Peterson, Alec Hopping). 1 at Ouray, 10 Sep (Amanda Ziegelbauer). Lamar Community College, Prowers, CERULEAN WARBLER: 1 at 12 Sep (Christine Alexander, Jesse Fox Ranch, Yuma, 9 Sep (Steven Casias, Renee Casias). 1 at Ken Caryl Mlodinow, Nick Moore). Valley, Jefferson, 21 Sep (David Sud- Northern Parula: 1 at Spring djian). Canyon Community Park near Fort Tennessee Warbler: 1 at Colorado Collins, Larimer, 4–14 Sep (Brad Big- State University, Larimer, 19–25 Nov gerstaff) and 6 Oct (Brad Biggerstaff). (David Wade, m.ob.); unusual for so 1 at Tamarack Ranch SWA, Logan, 7 late in the year. Other reports from Oct (Steve Larson, Van Remsen). 1 at

Colorado Birds Spring 2016 Vol. 50 No. 2 99 Gray Flycatcher, Chatfield State Park, Great Crested Flycatcher, Fort Lyon Jefferson County, 27 August 2015. Ditch, Prowers County 26 August Photo by Mark Chavez 2015. Photo by Janeal Thompson

Grasshopper Sparrow, juvenile, Larimer CR 5 north of Buckey Rd, Larimer County, 7 August 2015. Photo by Dave Leatherman

McCown’s Longspur, Weld CR 122 & Common Redpoll, Matthew Reeser 57, Weld County, 21 August 2015. Sanctuary, Larimer County, 1 Novem- Photo by Dave Leatherman ber 2015. Photo by Mark Chavez

100 Colorado Birds Spring 2016 Vol. 50 No. 2 Ash-throated Flycatcher, Melody Temple Northern Shrike, juvenile, Weld CR 99, Grove, Bent County, 27 August 2015. Weld County, 9 November 2015. Pho- Photo by Dave Leatherman to by Dave Leatherman

Union Reservoir, Weld, 21 Oct (Ste- Blackpoll Warbler: 1 near Arriba, ven Mlodinow, Sue Riffe). Lincoln, 7 Sep (Glenn Walbek). Magnolia Warbler: 1 at Boulder Black-throated Blue Warbler: 1 Res., Boulder, 17 Sep (Jackie DeMar- northeast of Deer Trail, Arapahoe, 13– co, Allan Sanford). 1 at Flagler Res. 14 Sep (Gene Rutherford, Loch Kil- SWA, Kit Carson, 4 Oct (David Dow- patrick). 1 at Stulp Ranch near Lamar, ell). Prowers, 9 Oct (Jane Stulp). Bay-breasted Warbler: 1 at Lake Palm Warbler: 1 at Ken Caryl Hasty, Bent, 8 Nov (Mark Peterson, Valley, Jefferson, 7 Oct (Stan Ma- Mike Henwood, Janeal Thompson, jlinger). 1 at Fox Ranch, Yuma, 9 Oct Michael Kiessig, Jane Stulp). (Joey Kellner, Kathy Mihm Dunning, Chestnut-sided Warbler: 1 in Glenn Walbek, Steven Mlodinow). Rye, Pueblo, 23 Aug (David Silver- 1 at Bear Creek Park, Denver, 25 Oct man). 1 at Clear Spring Ranch, El (Art Hudak, Scott Manwaring). Paso, 31 Aug (Steve Brown). 1 at Pre- Pine Warbler: 1 at Matthews-Re- witt Res., Washington, 6 Sep (Kathy eser Bird Sanctuary near Estes Park, Mihm Dunning, Joey Kellner, Chris Larimer, 5 Nov (Loch Kilpatrick). Owens). 1 northeast of Deer Trail, PRAIRIE WARBLER: 1 at Ken Arapahoe, 12 Sep (Gene Rutherford, Caryl Valley, Jefferson, 12 Aug (David Loch Kilpatrick). 1 at Washington Suddjian). Park, Denver, 15 Oct (Jeff Dawson). Black-throated Green Warbler: 1 1 at Fountain Creek Regional Park, northeast of Deer Trail, Arapahoe, 13 El Paso, 21–24 Nov (David Chartier, Sep (Gene Rutherford). 1 at Crow Val- m.ob.). ley CG, Weld, 4 Nov (Kevin Keirn).

Colorado Birds Spring 2016 Vol. 50 No. 2 101 Bushtit, “black-eared” form, Colorado State University PERC Gardens, Lar- imer County, 17 November 2015. Pho- to by Dave Leatherman

Golden-crowned Sparrow: 1 adult, Red-eyed Vireo, Lamar, Prowers Coun- returning for its sixth consecutive win- ty, 31 August 2015. Photo by Janeal ter, at Teller Farm & Lakes, Boulder, 25 Thompson Oct–8 Jan (David Dowell, m. ob.). Sagebrush Sparrow: 20 at Cheney Townsend’s x Black-throated Res., Mesa, 9 Oct (John Horn, Bill Green Warbler (hybrid): 1 at Crow Harris). Valley CG, Weld, 2 Sep (Steven Swamp Sparrow: 1 at Chuck Mlodinow, Austin Hess). Lewis SWA near Steamboat Springs, CANADA WARBLER: 1 near Routt, 14 Nov (JoAnn Riggle); rare in Arriba, Lincoln, 7 Sep (Glenn Wal- northwest Colorado. bek). Harris’s Sparrow: 1 in Meeker, Rio BAIRD’S SPARROW: 6 (3 Blanco, 29 Nov (Dona Hilkey); rare in adults then 3 juveniles) along Larimer northwest Colorado. County Road 5 northeast of Hamil- EASTERN TOWHEE: 1 at Crow ton Res., Larimer, during the period Valley CG, Weld, 21 Sep (Steven 25 Jul–12 Aug (Nick Komar, David Mlodinow) Wade, John Shenot, Austin Hess, Summer Tanager: 1 near Littleton, m.ob.). 1 near Genoa, Lincoln, 5 Oct CO, Jefferson, 4 Nov (Janet Shin). (Glenn Walbek). Painted Bunting: 1 at Ridgway LE CONTE’S SPARROW: 3 at SP, Ouray, 18 Sep (Amanda Ziegel- Fox Ranch, Yuma, 10 Oct (Ted Floyd). bauer). Fox Sparrow (Red): 1 in Colo- EASTERN MEADOWLARK: 1 rado Springs, El Paso, 10 Oct (Aaron (Lilian’s subspecies) at McIntosh Re- Driscoll). servoir, Boulder, 30 Jul–7 Sep (Johan- White-crowned Sparrow: 580 at na Beam, m.ob.). Jackson Res., Morgan, 29 Nov (Steven Rusty Blackbird: 1 at Riverbend Mlodinow, David Dowell). Ponds NA near Fort Collins, Lar-

102 Colorado Birds Spring 2016 Vol. 50 No. 2 Barn Swallow, Grandview Cemetery, Larimer County, 8 September 2015. Photo by Dave Leatherman

Winter Wren, Fountain Creek Regional Golden-crowned Kinglet, Grandview Park, El Paso County 29 November Cemetery, Larimer County, 31 October 2015. Photo by Bill Maynard 2015. Photo by Dave Leatherman imer, 24 Oct (Nick Komar). 1 at Stulp Res., Morgan, 2–7 Nov (Kathy Mihm Ranch near Lamar, Prowers, 5 Nov Dunning, Steven Mlodinow, Jonelle (Jane Stulp). 2 at Valco Ponds SWA, Balais, Bruce Cyganowski). 1 at Pre- Pueblo, 21 Nov (Chris Knight). 3 at witt Res., Washington, 21 Nov (David South Platte Park, Arapahoe, 28 Nov Dowell); unusual for so late in the (Ben Sampson). 2 at Barr Lake SP, year. Adams, 28–30 Nov (Christine Alex- Cassin’s Finch: 1 at Crow Valley ander, Norman Erthal). CG, Weld, 21 Sep–14 Oct (Steven Bullock’s Oriole: 1 at Jackson Mlodinow). 2 at Jackson Res., Morgan,

Colorado Birds Spring 2016 Vol. 50 No. 2 103 Varied Thrush, Stulp Farmyard, Prow- Sprague’s Pipit, Chico Basin Ranch, El ers County, 15 October 2015. Photo by Paso County 15 October 2015. Photo Jane Stulp by Bill Maynard

30 Sep–29 Nov (Dean Shoup, Steven Eaton Cemetery, Weld, 13 Nov (Ste- Mlodinow, David Dowell); uncom- ven Mlodinow). mon on the plains. White-winged Crossbill: 2 at Sil- PURPLE FINCH: 1 in Colo- verthorne, Summit, 19 Aug (Roger L. rado Springs, El Paso, 30 Oct (Marty Horn, Kathleen Horn). 1 at Powder- Wolf). 1 female type in Las Animas, horn Ski Area, Mesa, 5 Sep (Chris- Bent, 16–19 Nov (Duane Nelson). 1 tine Alexander). 2 at Rocky Moun- at Fountain Creek Regional Park, El tain NP, Grand, 30 Sep (Charlie Paso, 25 Nov (Chris Gilbert). Curlee). Red Crossbill (Western Hemlock Common Redpoll: Reports from / Type 3): 1 at Holyoke Cemetery, Arapahoe, Larimer and Logan, 29 Oct– Phillips, 24 Oct (David Dowell). 1 at 29 Nov.

ACKNOWLEDGMENTS The sightings reported by contributing observers to eBird, COBirds, and the West Slope Birding Network are greatly appreciated. Volunteer compilers contributed significantly to this report: Jim Beatty (southwest), Coen Dexter (west), John Drummond (southeast), Forrest Luke (northwest), Rich Miller, 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]

104 Colorado Birds Spring 2016 Vol. 50 No. 2 IN THE SCOPE

Lesser Nighthawk: Identification Pitfalls

Tony Leukering Elsewhere in this issue, Leukering (2016a) summarized the occurrence of Lesser Nighthawk (Chordeiles acutipennis) in Colorado. That article also provided a teaser for this column, which treats a number of unappreciated or under-appreciated problems in identifying the species in the state and elsewhere. Chief among these problems is a beast called Chordeiles minor henryi (hereafter “Henry’s”), the subspecies of Common Nighthawk that breeds in the southwestern United States. Though Lesser Nighthawk (hereafter “Lesser”) averages smaller than Common Nighthawk (hereafter “Common”), the difference is so small as to be only marginally useful in field identification, particularly when considering the range of size variation among the various subspecies of Common, five of which occur in Colorado (Bailey and Niedrach 1965). Pyle (1997) reports the range of wing chord (a widely used index of overall size) of Lesser as 158–196 mm (6.2–7.7 in) and that of Common as 163–210 mm (6.4–8.3 in), while Sibley (2014) notes little difference in overall length (Lesser 9 in [229 mm], Common 9.5 in [241 mm]). Thus, plumage characters are critical in Chordeiles identification, both in color and pattern, but also in relative lengths of individual feathers. Flying nighthawks present multiple characters by which well seen individuals can be identified [though see Sibley (2014) for difficulty of differentiating Common and Antillean (C. gundlachii) nighthawks in flight], with the plumage features touted as most useful being 1) the placement relative to wingtip or wrist of the pale primaries patch, 2) the relative lengths of the outer two primaries on each wing, and 3) buff spotting on the primaries of Lesser Nighthawk. Identifying perched nighthawks, however, can be surprisingly tricky, though perched birds can often be studied more closely and more thoroughly, offsetting the disadvantages. The mottled camouflage provided by the plumage of all nightjar species is complex and quite variable, both across and within species. This variability is exacerbated in nighthawks (and other nightjar species) by “possible chromatism (gray and brown plumages) in juv[enile]s (and possibly also adults)” (Pyle 1997). Additionally, juvenile plumage in the genus is different from that of adults of the same species: the white throat patch is absent or obscured, the pale primaries patch is reduced in size, the primaries have

Colorado Birds Spring 2016 Vol. 50 No. 2 105 distinct white or buff tips forming a contrasting trailing edge (Pyle 1997), the plumage is overall paler by subspecies, and the scapulars are relatively plain brown, lacking Fig. 3. Note the placement of the relatively non-contrasting the “bold, black pale primaries patch relative to the tertials and the buff spot- and buff pat- ting on the bases of the outer primaries on this female Lesser tern” (Pyle 1997) Nighthawk. Chico Basin Ranch, Pueblo County, CO, 28 May typical of adult 2010. Photo by Bill Maynard scapulars. Final- ly, males in all but juvenile plumage sport a wide subterminal white band on both inner and outer webs of the tail feathers (so visible from both above and below), a feature lacking in females. Also important in nighthawk identification is foraging behavior. Lesser has a strong tendency to forage low over water or other habitat features (Sibley 2014, W. Russell pers. comm.). While Common also frequently forages at low altitude, the species is much more likely to be seen foraging at relatively high altitudes than is Lesser, thus suggesting that low-foraging nighthawks receive particular attention from those searching for Lesser.

Fig. 1 (back cover). Note the nearly equilateral triangle shape to that part of the wingtip beyond the pale primaries patch and that p10 is shorter than p9 on this adult male Lesser Nighthawk. Also note the rows of buff spots on the secondaries and primaries, particularly the buff spots on the bases of the outer primaries, a feature not matched in any form of Common Nighthawk. See text for details of ageing and sexing. Aravaipa Canyon, Pinal County, Arizona, 10 June 2014. Photo by Ned Harris

Fig. 2 (back cover). Note the attenuated triangle shape to that part of the wingtip beyond the pale primaries patch and that p10 is (barely) longer than p9 on this adult male Common Nighthawk. This illustration represents probably the least equilateral- triangle shape in the species, as the hand is completely extended. The shape of the triangle can vary in a single individual depending upon how the wingtip is held. Note also that among the primaries, only p1–2 sport even vague spotting. See text for details of ageing and sexing. Carrizo Work Center, Comanche National Grassland, Baca County, CO, 31 May 2011. Photo by Tony Leukering

106 Colorado Birds Spring 2016 Vol. 50 No. 2 to vagaries of how an individual holds its wing, the patch may be obscured by the tertials or other feathers, though with the more-interior po- sition on Common, the patch on that species seems more likely to be obscured Fig. 4. Note the placement of the pale primaries patch rela- than that of Lesser. tive to the tertials, as well as the typical stair-step shape of However, the female the patch, on this adult Common Nighthawk. The date Lesser Nighthawk’s and location of the photograph strongly suggest that this buffy patch can be bird is referable to henryi, a contention supported by the difficult to discern in fairly buffy appearance to the plumage. Yeso, De Baca many situations, as County, NM, 12 June 2011. Photo by Jerry Oldenettel it gets lost in all the other buffy bits on the primaries, though it is the most-distal bit of buff on each of those primaries (Fig. 3). Relative lengths of p9 and p10. Adult Commons typically have every successive primary from the in- nermost (p1) to the Fig. 5. Note the placement of the pale primaries patch rela- outermost (p10) lon- tive to the tertials, and the nearly straight distal edge of the ger than the preced- patch, on this male Lesser Nighthawk, which exhibits oddly ing one, resulting in little buff spotting on the bases of the primaries. Santa Ana the longest primary N. W. R., Hidalgo County, TX, 22 February 2005. being the outermost Photo by Marshall J. Iliff (Fig. 2 on back cover). However, some individuals exhibit the two outermost (p9 and p10) being of equal length (Pyle 1997) or, even, with p10 being slightly shorter than p9 (15 of >140 adult Commons in pictures on Flickr showed p10

Colorado Birds Spring 2016 Vol. 50 No. 2 107 Fig. 6. This juvenile Common Nighthawk exhibits the white trailing edge to the primaries typical of the plumage class, as well as having p10 shorter than p9. Cape May Point S. P., Cape May Co., NJ, 18 September 2013. Photo by Tom Reed

Fig. 7. This Common Nighthawk shows Fig. 8. The extensive buff spotting to the the buff spotting on the primaries typi- primaries strongly suggest that this bird cal of henryi, providing, apparently, the is referable to Henry’s Common Night- first record of the taxon from the county. hawk. Ageing as a juvenile is straight- Crow Valley Campground, Pawnee forward, with the lack of a white throat National Grassland, Weld County, patch, small size of the pale primaries CO, 30 July 2011. Photo by Steven patch, and the obvious pale tips to the G. Mlodinow primaries. Crow Valley Campground, Pawnee National Grassland, Weld County, CO, 12 August 2015. Photo by Steven G. Mlodinow

108 Colorado Birds Spring 2016 Vol. 50 No. 2 In the discussion below, I expanded on my personal experience with these two species (Common n>10,000, Lesser n>200) by study- ing pictures on Flickr (www.flickr.com) of nighthawks with wings open (Common n>220, Lesser n>50) and folded (Common n>125, Lesser n>60). Among Common Nighthawks, I studied subsamples of birds in juvenile plumage (n=23; photos taken in August and Sep- tember) and those that I determined to be in their second calendar year of life (SY; photos taken in May through August), that is about one year of age (n=12). Finally, I noted the p9:p10 ratio on a sub- sample of >140 apparent adult Commons. Pale primaries patch. A large, pale patch cuts across the outer 4–6 primaries (p5–p10) on Chordeiles nighthawks. On Commons, this patch is white and is present on at least five primaries (p6– p10), extending to p5 on many (most?) and even onto p4 in a small minority (adult males?; pers. obs.). On Lessers, the patch is white in males, buff (to off-white?) in females, and extends only to p7 in most, but extending to p6 on a minority (e. g., https://www.flickr. com/photos/finaticphotography/11197122063; again, adult males?). However, determining which and how many primaries are involved in the pale patch is difficult, often impossible, to discern in the field. Thus, for nighthawks in flight, determining the placement of this patch relative to the wingtip and wrist is the critical feature (Pyle 1997, Sibley 2014). On Commons, the patch is just a bit closer to the wingtip than halfway out the wing from the wrist, while on Lesser it is nearly ¾ the distance toward the wingtip from the wrist. The result of this different placement might best be determined by the appearance of the shape of the wingtip beyond the pale patch, which is roughly an equilateral triangle (sides all of about equal length) in Lesser, but a triangle in Common that is taller than the base is wide (Figs. 1 and 2 on back cover). The pale primaries patch on female Lessers is of such low contrast with the wing (and none at all with the buff primary spotting) that the patch can be difficult to discern (Fig. 3), particularly in low-light conditions. Thus, a nighthawk with no discernible pale patch in the ABA area is a female Lesser. On perched nighthawks, however, it is the placement of the pale patch relative to the tertials that is important. On Common, the leading edge of the patch is typically about even with the bases of the tertials (Fig. 4), while on Lesser it is about even with, or just short of, the tip of the longest tertial (Figs. 3 and 5; Sibley 2014). Common also has a strong tendency for the distal (away from the body) edge of the patch to have a stair-step shape cutting diagonally away from the edge, while this appearance is reduced or absent in Lesser. Due

Colorado Birds Spring 2016 Vol. 50 No. 2 109 it contributes greatly to the overall more-rounded appearance of the wingtip of Lesser. Of course, the situation is not as straightforward as all that (we are discussing biology!) and there are caveats involving age and molt. Commons, like virtually all birds, leave the nest in juvenile plumage (= first basic plumage; see Leukering 2010). In my sample of 23 individuals of Common Nighthawk in juvenile plumage (in 21 pictures posted to Flickr; see introduction), the exact wingtip formula was determinable in 20. Of those 20, 18 birds had p10 shorter than p9, thus supporting my understanding of this difference in wingtip shape obtained through personal observation of nighthawks (Fig. 6). Since the juvenile flight feathers are retained through the species’s preformative molt, a Common Nighthawk that sported a p10 shorter than its p9 in its first month of life will exhibit the same appearance when about a year old in the following summer. [In my sample of 12 apparent SY Common Nighthawks, seven exhibited a shorter p10. This apparent discrepancy in proportions between juvenile plumage (90%) and formative plumage (58.3%) is due to one or more of four causes: 1) an effect of small sample size, 2) my mis-ageing of the subject birds, 3) misunderstanding of the molt strategy of the species (Pyle 1997), and 4) the continued growth of p10 such that the true length of p10 is achieved only after leaving the ABA area. I believe that the first two causes are the most likely, particularly the second, though the fourth has some merit.] Thus, ageing the subject nighthawk is critical to understanding whether the bird’s p10 being shorter than its p9 has species-identification usefulness. Finally, wing-molt strategies of the two differ quite dramatically in adults, with Lesser molting on or near the breeding grounds and Common molting on South American winter grounds. Throw- ing a monkey wrench into an otherwise clear-cut situation is the fact that one-year-old Commons initiate wing molt on or near the breeding grounds and can conduct half (or more) of the wing molt north of Mexico (e.g., https://www.flickr.com/photos/michael_rosen- baum/3849448932). Buff markings on primaries. Another feature touted as a differentiating characteristic between Lesser and Common nighthawks is the rows of buffy spots on Lesser primaries, a feature that is “supposed” to be lacking on Commons. While the secondaries are spotted on all Lessers (buff), many Commons exhibit secondary spotting (buff to white). [Since the secondaries are typically not visible when the wing is folded, the spotting is of little consequence to identification of such birds. Care should be used in determining which feathers are spotted, as a brief view of spotting on the outer secondaries of a flying night-

110 Colorado Birds Spring 2016 Vol. 50 No. 2 hawk might be construed as spotting on the inner primaries. Note also that the secondaries are mostly hidden in many wing postures as seen from below on nighthawks, as the long—and spotted—greater coverts obscure most of the length of the secondaries (Fig. 1).] In fact, though, a small percentage of individuals of most or all subspecies of Common have at least a few spots on one or two inner primaries, though these spots seem to be small and not obvious. However, we have now reached the main reason behind this essay: unlike all other subspecies of Common, Henry’s exhibits extensive buff spotting on the secondaries and inner primaries, thus engendering the possibility of additional confusion with Lesser.

Henry’s Nighthawk The precise breeding range of Henry’s has yet to be worked out, nor do we know what happens where this taxon meets other subspecies of Common (hesperis to the north and west, howelli to the north and east). The Common Nighthawk subspecies map in NGS (2014) presents henryi as occupying only the very southwest corner of Colo- rado, while Pyle (1997) notes the species as breeding from southeastern Utah to southeastern Colorado south to southern Arizona and western Texas, with vagrancy to, at least, Florida. However, Bailey and Niedrach (1965 and references therein) note Henry’s as breeding “in Mesa and southwestern counties,” citing specific specimens housed at the Denver Museum of Nature & Science from Archul- eta (#3148), La Plata (#s 3219–3223), and Mesa (#s 22157–22159) counties, all taken in July. Additionally, apparent Henry’s have been photographed on multiple occasions in Weld County, a male and a juvenile in different years at Crow Valley Campground, Pawnee Na- tional Grassland (Figs. 7 and 8). Despite the individual variation typical of nighthawks, there are quite a few features of Henry’s that may permit subspecific identification, chief among them being the rows of large buff spots on the inner five primaries, a feature that is, to greater or lesser extent, lacking in other subspecies of Common Nighthawk. Adults exhibit brown- ish upperparts with “coarse, buff or tawny mottling giving an overall cinnamon appearance” and with underparts “buffy, with moderately narrow dusky bars” (Pyle 1997). These features are fairly different from those of howelli (the breeding subspecies in much of the rest of Colorado, excepting the northern plains)—“upperparts pale brown- ish with buff mottling” and “underparts whitish buff with moderately wide, dusky bars”—and sennetti (the northern-plains breeding subspecies)—“upperparts medium-pale grayish, without buff tones” and “underparts whitish with narrow, dusky bars” (all Pyle 1997).

Colorado Birds Spring 2016 Vol. 50 No. 2 111 As noted previously, juveniles of each of these subspecies tend to be paler than adults of the same subspecies, with juvenile sennetti being particularly paler (Sibley 2014; “juvenile northern plains”).

A Call to Arms, er, Cameras Despite the great advances that recent birding effort has made in understanding the geographical and temporal occurrence patterns of Colorado’s birds (Leukering 2016b), there is still a plethora of such topics about which we know very little. Heretofore, subspecies distribution has been the province of ornithology, with little that birders could do to advance our understanding. While there are many as- pects of ornithology to which birders cannot contribute in meaning- ful ways, with the advent of high-quality, relatively low-cost digital SLR cameras, that line between ornithology and birding in regards to subspecies ranges has been blurred quite a bit. Bailey and Niedrach (1965) noted four subspecies of Common Nighthawk as breeding in Colorado—Western (hesperis), Henry’s, Howell’s (howelli), and Sennett’s (sennetti)—and noted Eastern (mi- nor; which is better called “Northern/Eastern”) as a migrant through the state. Unfortunately, the number and geographical distribution of nighthawk specimens with which they had to work was limited, and much about the distributions of, particularly, the four breeding taxa remains to be discovered. Photographer–birders can assist in that effort. I have created a group on Flickr called “Colorado Nighthawks” (www.flickr.com/groups/coloradonighthawks/) which aims to do just that. I encourage birders to submit high-quality images to that group as a first step in enabling us to tackle this problem. While photos of nighthawks from anywhere in the state are needed, of particular interest and need are pictures of nighthawks from the West Slope, the San Luis Valley, and the southern plains. The pictures would also need to be geo-referenced in Flickr by plotting the precise locations at which individual photos were taken (some cameras and all smart phones—given suitable reception—provide such automatically). Photos of both perched and flying nighthawks are useful, with pictures of flying birds being particularly helpful in identifying Henry’s. Finally, I ask that birders salvage any nighthawks found dead that are still in good condition and get them to the Denver Museum of Nature and Science’s collection (or other accredited collection); such specimens provide the underpinnings of virtually all that we know of the distribution of species of birds, particularly at the subspecies level. For each salvaged bird, please provide the details of when (date), how (e.g., road kill), and where (be specific) the bird was found, preferably written in waterproof ink (e.g., with a gel pen), on

112 Colorado Birds Spring 2016 Vol. 50 No. 2 a piece of paper that is kept with the bird. Put the bird (and the details) in as large a waterproof plastic bag as will permit the bird to fit without bending wing feathers and keep it frozen until it is delivered (hopefully sooner, rather than later) to the Museum.

Acknowledgments I greatly appreciate review of a previous version of this manuscript by Will Russell and his suggestion of rationale 4 in the assessment of p10 length in the first year of Common Nighthawk life. I also thank Peter Pyle for discussion about nighthawk molt strategies, Kathy Mihm Dunning for clarifying my thinking about wingtip triangles, and a particular henryi Common in Louisiana (that I didn’t even see) for restoking my interest in nighthawk subspecies ID and distribution (after years in the East where there is only one; how boring). However, my greatest thanks go to Alfred M. Bailey and Robert J. Niedrach for writing what I consider to be the epitome of state-level bird books and providing me so many, many hours of enjoyment tiptoeing (sometimes galumphing) through that tome, which provides such a strong base for my own explorations of Colo- rado bird distribution in this venue. If I could produce something even half as interesting and useful, I would die happy.

Literature Cited Bailey, A. M., and N. J. Niedrach. 1965. Birds of Colorado. Denver Museum of Natural History, Denver, CO. Leukering, T. 2010. Molt and plumage: A primer. Colorado Birds 44:135–142. http:// cobirds.org/CFO/ColoradoBirds/InTheScope/24.pdf Leukering, T. 2016a. Lesser Nighthawk in Colorado. Colorado Birds 50:121–124. Leukering, T. 2016b. Colorado’s bird list, decadal species accumulation, and comments on the state’s 500th species. Colorado Birds 50:114–117. National Geographic Society [NGS]. 2014. Complete Birds of North America. Second edition. National Geographic Society, Washington, DC. Pyle, P. 1997. Identification Guide to North American Birds, part I. Slate Creek Press, Bolinas, CA. Sibley D. A. 2014. The Sibley Guide, 2nd ed. Alfred A. Knopf, New York, NY.

Tony Leukering, 1 Pindo Palm St. W, Largo, FL 33770 ([email protected])

Colorado Birds Spring 2016 Vol. 50 No. 2 113 Colorado’s Bird List, Decadal Species Accumulation, and Comments on the State’s 500th Species

Tony Leukering

Just nine U.S. states have bird lists of 500 or more species. Of those, only two (Arizona and New Mexico) are non-coastal. Perched at 499 species, as Colorado approaches that major milestone many birders are looking forward, endeavoring to predict the next species to be added, as shown by the article in the previous issue of this journal (Burke 2016). One part of this essay is in response to that very article. While I, too, have been pondering that question, I thought it a good time to ponder how we arrived at the cusp of joining the 500 Club. What is the history of the accumulation of species to the state’s bird list? Answering that question required a bit of delving into the history of Colorado ornithology in general and specifically into the Colorado Bird Records Committee (CBRC). The CBRC was organized as the Colorado Field Ornithologists Official Records Committee in 1972 (Reddall 2012) and published an official list for the state totaling 428 species (Reddall 1973). With the establishment of rigorous standards to which reports of future first state records would be applied, that total of 428 is a reasonable place to start on the road of figuring out from where we have come. Unfor- tunately, using 428 as a starting point ignores the problem of changes in taxonomy. Changes since the early 1970s in the American Ornithologists’ Union’s taxonomy (used by CBRC) were driven primarily by new data and by alteration in how hybridization in birds is viewed. In the intervening time period, many taxa considered species in 1972 have been lumped into fewer species, but more-recent direction changes have caused some to be re-split into species-level taxa. So, while Bull- ock’s Oriole disappeared (merged with Baltimore Oriole into North- ern Oriole) and then reappeared, the lump of Myrtle and Audubon’s warblers into Yellow-rumped Warbler has not been reversed (despite differences in plumage, call notes, songs, and migration strategies). Thus, to put the starting point level with today’s taxonomy, we need to subtract nine species (Black Brant, Blue Goose, Mexican Duck, Harlan’s Hawk, Red-shafted Flicker, Audubon’s Warbler, and Ore- gon, Slate-colored, and White-winged juncos) from that 428 total,

114 Colorado Birds Spring 2016 Vol. 50 No. 2 leaving 419; all nine of those were treated as separate species when the first official CFO list appeared. Although we might now choose to start with the 419 figure, during the early years of the CBRC and with the publication of An- drews and Righter (1992 and references therein), the documentation for eleven species (Mottled Duck, Common Eider, Ruffed Grouse, Parasitic Jaeger, Iceland Gull, Inca Dove, Crested Caracara, Black Phoebe, and Hooded and Scott’s orioles) was found to be insufficient or was shown to support identification as a different species. Those species were removed from the state list, leaving just 408 species. (I find it interesting that 10 of those 11 species deleted have occurred subsequently, with only Common Eider still outstanding.) On the positive side of the ledger, taxonomic changes made after 1972 involved taxa considered subspecies in 1972, but which were definitively known from the state in 1972 or, in one case, known to be present but not described even at the subspecific level at the time. So, we can add Cackling Goose, Gunnison Sage-Grouse, Thayer’s Gull, Western Screech-Owl, Red-naped Sapsucker, Alder Flycatcher, and Cassin’s Vireo. That brings our starting true tally to 415 and per- mits us to get to the heart of this essay: the addition of species to the Colorado bird list between the 1960s and the present. In Table 1, I present a summary of the complete Colorado bird list, current as of the addition of Vaux’s Swift to the list as the result of a sighting in April 2015 (Peterson and Maynard 2015), with the number of first state records tallied by time period. The 1970s was clearly the heyday of additions to the Colorado list, Table 1. Temporal occurrence of the first accepted with 31 species added. Al- records of the 499 bird species on the Colorado though the decade’s total of state list (as of 2015). first state records was assisted by an increasing number of Time period Number of first state records birders in the state, I believe pre-1960s1 395 that a large measure of the 1960s 9 credit goes to the establish- 1970s 31 ment of the CBRC and the 1980s 18 corresponding rigor with which new species were doc- 1990s 19 umented. Witness, again, 2000s 20 the 11 species removed from 2010s 7 the state list after Reddall Total 499 (1973), which were removed 1 This period's total includes species noted in the state before 1960 along for lack of firm details or with a small number of species for which I was unable to determine the misidentified specimens, and decade of first occurrence.

Colorado Birds Spring 2016 Vol. 50 No. 2 115 the subsequent addition of ten of those due to the submission to the CBRC of definitive details. In effect, the 1970s total was the benefi- ciary of less-rigorous efforts in prior decades, particularly the 1960s, during which just nine species were added to the state list. I also note that the current decade seems to be running behind the average of 19 additions per decade of the three previous decades. Is the state list finally revealing the law of diminishing returns? Lastly in this vein, I consider Table 1 to be a slapdash effort; someone with serious data and archival interests could do a much better job by providing a similar table with the discovery year for each and every species. Several birders quoted in Burke (2016) noted the possibility of the state’s 500th species having already occurred, but that current taxonomic treatment hides that fact. Indeed, there are many good possibilities of species splits that would provide the state with one or more additional species. Among those possibilities with published evidence supporting a split are Mallard (McCracken et al. 2001), Warbling Vireo (Sibley and Monroe 1990), White-breasted Nut- hatch (Spellman and Klicka 2007, Walstrom et al. 2012, Pandol- fino and Pieplow 2015), Marsh Wren (Kroodsma 1989), Swainson’s Thrush (Ruegg 2008), Yellow-rumped Warbler (Milá et al. 2007), Fox Sparrow (Zink and Weckstein 2003), and Eastern Meadowlark (Barker et al. 2008), each of which would add one species to the state list, and Red Crossbill (Groth 1993), which could add as many as four species to the state list. Although I believe that the chances are slim that any of these potential splits will be approved before the 500th species is notched, the point that I wish to make about the discussion in Burke (2016) is that it is not just splits in the offing; there is also a “dark” side to taxonomic reapportionment. The rosy-finches (Drovetski et al. 2009) and the redpolls (Mason and Taylor 2015) have both been proposed for lumping, with a potential net loss of three Colorado species. In my opinion, the redpolls are more likely than the rosy-finches to be lumped in the near future, as the published science behind the proposal is fairly strong (which is not the case, so far, for the rosy- finches). I am just saying.

ACKNOWLEDGMENTS I thank Dr. J. Van Remsen for a thorough review of a previous version of this essay. I also thank Doug Faulkner and Van Remsen for assistance at tracking down references.

LITERATURE CITED Andrews, R., and R. Righter. 1992. Colorado Birds: A Reference to Their Distribution and Habitat. Denver Museum of Natural History, Denver, CO.

116 Colorado Birds Spring 2016 Vol. 50 No. 2 Barker, F. K., Vandergon, A. J., and S. M. Lanyon. 2008. Assessment of species limits among yellow- breasted meadowlarks (Sturnella spp.) using mitochondrial and sex- linked markers. The Auk 125:869–879. Burke, P. 2016. The race is on! Who will identify Colorado’s 500th species of bird? Colo- rado Birds 50:305–316. Drovetski, S. V., R. M. Zink, and N. A. Mode. 2009. Patchy distribution belies morphological and genetic homogeneity in rosy-finches. Molecular Phylogenetics and Evolution 50:437–445. Groth, J. G. 1993. Evolutionary differentiation in morphology, vocalizations, and al- lozymes among nomadic sibling species in the North American Red Crossbill (Loxia curvirostra) complex. University of California Publications in Zoology, no. 127. Kroodsma, D.E. 1989. Two North American song populations of the Marsh Wren reach distributional limits in the central Great Plains. The Condor 91:332–340. Mason, N. A., and S. A. Taylor. 2015. Differentially expressed genes match bill morphology and plumage despite largely undifferentiated genomes in a Holarctic songbird. Molecular Ecology 24:3009–3025. McCracken, K. G., W. P. Johnson, and F. H. Sheldon. 2001. Molecular population genetics, phylogeography, and conservation biology of the Mottled Duck (Anas fulvigula). Conservation Genetics 2:87–102. Milá, B., T. B. Smith, and R. K. Wayne. 2007. Speciation and rapid phenotypic differentiation in the Yellow-rumped Warbler Dendroica coronata complex. Molecular Ecology 16:159–173. Pandolfino, E. R., and N. D. Pieplow. 2015. Comparison of vocalizations of four U.S. subspecies of the White-breasted Nuthatch. Western Birds 46:278–290. Peterson, M., and B. Maynard. 2015. The 72nd report of the Colorado Bird Records Committee. Colorado Birds 49:221–238. Reddall, J. 1973. Official state list of the birds of Colorado as of June 1, 1973. Colorado Field Ornithologist 17:3–14. Reddall, J. 2012. The Colorado Field Ornithologists’ Colorado Bird Records Committee: Twenty-five years (1972–1996). Colorado Birds 46:45–49. Ruegg, K. 2008. Genetic, ecological, and morphological characterization of a hybrid zone that spans a migratory divide. Evolution 62:452–466. Sibley, C. G., and B. L. Monroe Jr. 1990. Distribution and Taxonomy of Birds of the World. Yale University Press, New Haven, CT. Spellman, G. M., and J. Klicka. 2007. Phylogeography of the White-breasted Nuthatch (Sitta carolinensis): Diversification in North American pine and oak woodlands. Mo- lecular Ecology 16:1729–1740. Walstrom, J. W., J. Klicka, and G. M. Spellman. 2012. Speciation in the White-breasted Nuthatch (Sitta carolinensis): A multi-locus perspective. Molecular Ecology 21:907– 920. Zink, R. M., and J. D. Weckstein. 2003. Recent evolutionary history of the Fox Sparrows (genus: Passerella). The Auk 120:522–527.

Tony Leukering, 1 Pindo Palm St. W, Largo, FL 33770; [email protected]

Colorado Birds Spring 2016 Vol. 50 No. 2 117 FULLY EXPOSED

Amateur Bird Videography Editing

Bill Schmoker In my last column I discussed some tips and tricks for adding video to your repertoire when you are out photographing birds. As with still photography, the process shouldn’t be considered over when your birding time ends. Here I’d like to review some very basic video editing that can help to make the most of the amazing footage you are bound to record! Since software and computer systems vary widely, I’ll focus on the types of things I like to do with my videos instead of extensive descriptions of the steps I take. For detailed how-to’s, lots of tutorials exist on YouTube or on various websites so use your Google-Fu to crack these nuts if you get stuck. As you might expect, there are plenty of parallels between working with digital stills and video. With either, once back from the field I recommend starting out by reviewing your files. Delete anything that isn’t worth keeping, rename what you want to save, and archive your files. Naming conventions and archiving schemes are hugely varied, but be consistent with whatever you use. I like to have banding codes in my file names so they are easy to search for, and for video I also often include a location and date. For example, if I filmed a Sharp-shinned Hawk eating a House Finch yesterday in my back yard, I might name the clips something like SSHA_HOFI_Longmont_22Feb2016-1.mp4, the next one SSHA_HOFI_Longmont_22Feb2016-2.mp4, etc. I find Adobe Lightroom’s Library Module to be an excellent platform for reviewing/deleting/naming both still and movie files. I keep any movie files along with stills from the day’s shooting in a folder named with location and date, and I back up my folders frequently. As with naming conventions, there’s no single “right” way to do any of this, just be sure to find a routine that is easy and consistent to streamline your digital workflow. One difference to think about with video is that part of any clip might be worth using even if the rest is crummy. This creates a bit more time-intensive process when deciding what to keep in comparison to stills, which usually get a quick keep or delete decision. This also brings up the first editing tool to have in your video bag of tricks: trimming clips to extract the parts of any movie you want to use. My editing software of choice here is iMovie, mainly because it comes included with my MacBook’s system software. There are undoubtedly many other great software choices and ways to trim clips, but the main point here is to plan on this step. In iMovie, I use the “split clip” option to isolate what I want to use, deleting the trimmed-out portions.

118 Colorado Birds Spring 2016 Vol. 50 No. 2 If a trimmed clip has problems with exposure, there are adjustments that can be made similarly to stills. Basic adjustment of light levels, color saturation, and white balance can be adjusted to suit your cre- ative eye. Clips can be cropped, though I would use this sparingly as resolution will be lost when the remaining pixels fill the movie frame. Cropping potential will increase, however, if you set your camera to record at the highest available resolution. For example, many newer cameras have the option of recording 4k video. With this resolution you can crop a clip to a fair degree and still retain HD-quality in your finished product (see www.4k.com/resolution for a nice illustration of this). There are also options in iMovie to reduce shake or fix a “rolling shutter” effect of motion distortion caused by quick panning. A crucial dimension of videos that can also be edited is the audio component. Overall sound levels can be increased or decreased, or can be muted altogether. If narration is your thing you can record voice-overs or even a musical soundtrack. More nuanced sound editing tools can be brought into play such as reducing background noise (which can help in some situations such as cutting back wind or traf- fic sounds) or equalizer settings such as hum reduction (which can help with noise from optical image stabilizing motors). Wind noise can be the bane of outdoor video and audio recording, and if you are interested in delving deeper into strategies for reducing this problem check out Michael Gallagher’s excellent treatment of the subject: http://bit.ly/ReduceWindNoise. Another dimension unique to motion pictures is the ability to manipulate time. There are three ways I’ve played with this, but perhaps the most useful for bird photography is slow-motion. If you are planning on trying this, check your camera manual to see if there is a high-speed video shooting mode. This means that the camera will record frames faster than the normal 24–30 frames per second rate, allowing smoother footage when you dial back the seg- ment speed for slow-motion effect. Many smart phones also have a slow-motion mode baked into their native camera app, which can make for pretty neat phone-scoped bird footage. Even if you shoot in normal mode, you can slow down parts of a clip to better empha- size details you desire but there will be an increasingly jumpy effect as the frame rate drops. Here’s a movie of a Tree Swallow I made last summer featuring slow motion: youtu.be/nJdXqYZYkdc. Another trick that can be used for emphasis is to feature a freeze-frame within a movie clip to linger on for as long as you want. The freeze frame can also be used as a still image to append to eBird checklists etc. (eBird doesn’t currently allow for direct uploading of video clips). On the other time-manipulation extreme, you can speed up clips

Colorado Birds Spring 2016 Vol. 50 No. 2 119 for a time-lapse effect. I haven’t used this for birds but as I’m writing this I’m imagining that it could be pretty cool for documenting a nest-building bird (strictly following ABA Principals of Birding Ethics, of course), showcasing an evening fly-in of cranes, or watch- ing the ebb and flow of birders somewhere busy like Magee Marsh during spring migration. While not a birding movie, here’s a time lapse I put together of the Sun tracking low above the horizon at the North Pole last summer: youtu.be/xOCCSegL8ic. Once you’ve mastered trimming and editing clips, making a finished movie isn’t really much more difficult. I try to let “short & sweet” be a guiding principle, assembling clips to tell whatever little story I’m going for. I like to put simple transitions such as cross- dissolve or cross-blur between clips to make the movie seem a little smoother. Including captions or titles with whatever information you might like to include such as subject, location, and date can add a nice touch. Then it is a matter of hosting and/or sharing your video. I use YouTube because it is an easy, free, and a widely acces- sible platform. You can also keep movie files online with services such as DropBox to share as desired. If I have video to include with an eBird checklist I just paste the URL into the comments section for the checklist or the bird, depending on the situation. Speaking of YouTube, here’s one more video to leave you with, this time from last summer’s ABA Camp Colorado. This one incorporates both human and bird elements, and demonstrates how simple editing can produce a fun movie that can be shared and enjoyed by many: youtu.be/OkdQyPcWXIg.

Bill Schmoker, [email protected]

120 Colorado Birds Spring 2016 Vol. 50 No. 2 Lesser Nighthawk in Colorado

Tony Leukering Editor’s note: With this essay Colorado Birds initiates a new column, which will be fo- cused on the Colorado occurrence patterns, both in time and space, of particular species. The column will spotlight species or subspecies that meet at least one of three criteria: 1) patterns of occurrence have changed, usually dramatically, since the publication of the last comprehensive work on the state’s avifauna, Colorado Birds by Robert Andrews and Robert Righter (1992), such as Black Phoebe; 2) our understanding of occurrence parameters has changed since 1992, such as Lesser Nighthawk; or 3) data obtained since 1992 provides a considerably finer-scale understanding of patterns of occurrence (such as White-winged Junco). The column will not treat identification, except cursorily where important in understanding distribution—identification will continue to be the domain of the “In The Scope” column. An entry may not appear in every issue and authorship will vary. Anyone wishing to suggest a topic species or author a column should contact the Editor.

Lesser Nighthawk has a somewhat checkered history in Colorado, being first noted here in 1908, but without a subsequent accepted record until 1987. Since then, there has been a plethora of reports scattered on both sides of the state. I here provide a synopsis of the species’s Colorado occurrence, based on the records accepted by or reports currently circulating through the Colorado Bird Records Committee (hereafter CBRC or Committee) or supported by specimens housed at the Denver Museum of Nature & Science (DMNS), omitting all other reports, except for those germane to the ending discussion. Below, all geographical names refer to counties, unless otherwise noted.

Early Years In their seminal work, Bailey and Niedrach (1965) listed two Colorado records of Lesser Nighthawk, both collected by Charles Aiken: an adult female at Hoehne, Las Animas County, on 11 June 1908 (DMNS accession #26006) and an “immature” at Colorado Springs, El Paso County, on 25 August 1922 (DMNS #26007). However, Webb and Reddall (1989) corrected the identification of the latter specimen to Common Nighthawk, leaving the Las Animas County record as the state’s sole occurrence until the late 1980s.

1980s and 1990s The last three decades of the previous century, particularly the final two, saw a great increase in the intensity and distribution of birding effort in the state (Andrews and Righter 1992, Kingery 1998, Leukering 2016a, Wickersham 2016). This increased effort has led to a far better understanding of what birds occur in the state and when and where they do so. During this period, 13 occurrences of Lesser Nighthawk were documented, with the state’s second and third occurrences of Lesser Nighthawk being noted 20 June 1987 (Montrose; DMNS

Colorado Birds Spring 2016 Vol. 50 No. 2 121 #39386; Janos and Prather 1989) and 27 May 1988 (Baca; DMNS #40000); the other 11—in Baca (3 records), Larimer (2), Mesa (3), Otero (1), and Prowers (2)—were all from the 1990s, but with four in 1995.

2000–2009 Seven additional records accrued during this decade, two from Pueblo (2001, 2008), one from Kiowa (2003), two from Dolores (both 2006), and two from Montrose (2006, 2008).

2010–2015 The 2010s started off with a bang, with four records of Lesser Nighthawk tallied in 2010, one each from Boulder, Cheyenne, Montrose, and Pueblo. Two reports from 2011 have been accepted, both from Montrose, while Kiowa scored its second Lesser Nighthawk in 2013. Single reports from each of 2014 and 2015 are currently in review by the CBRC. Notably, many additional Lesser Night- hawk sightings from those years have not been submitted to the Committee.

Seasonal Occurrence Lesser Nighthawks begin to arrive on their U.S. breeding grounds during March, with the first Arizona breeders, particularly those in southwestern Ari- zona, first appearing in early March, and California breeders (except for the southeastern corner?) first arriving in late March (Latta and Baltz 2012). Thus, the species arrives a month or so before Common Nighthawk (Brigham et al. 2011). While a few Common Nighthawks are found each year in Colorado in the first half of May, the species does not exhibit a Colorado frequency of >2% on eBird checklists until the last week of May and does not achieve peak frequency (7.9%) on eBird checklists until early June (eBird 2016). This means that Lesser Nighthawk is, relative to overall Colorado nighthawk abundance, more common in Colorado in April and early May than at any other time. Except for one of the 2011 Montrose records (more on that below), no accepted Colorado records span multiple months. This fact may suggest that, for the most part, Lesser Nighthawks occurring in the state are of brief occurrence, departing shortly after being found. In fact, only four of the 27 records have supporting documentation for more than one date. However, most of the locations of accepted records are quite distant from the state’s human-population centers (thus of birders’ residences). Therefore, observer effort (and the difficulty of refinding a cryptically marked bird that often roosts on the ground) likely contribute to this “one-day-wonder” phenomenon. The full span of Colorado occurrence runs from 16 April (Pueblo, 2001) through 10 September (Larimer, 1995), though the 26 single-month records are fairly tightly clustered in the last half of spring, with 13 in the period 1 May–10 June (Table 1). Interestingly, 11 of these 13 records account for the lion’s share of the 16 East Slope records. There are an additional four June records, four

122 Colorado Birds Spring 2016 Vol. 50 No. 2 from July, one from August, and two from September. Also very interesting is the fact that West Slope records account for eight of the 12 post–10 June records (again, more on this below).

Does Lesser Nighthawk Breed in Colorado? Despite the range maps in several well-known sources indicating that Lesser Nighthawks breed no closer to Colorado than central Arizona and New Mexico (e.g., Latta and Baltz 2012, Sibley 2014), there is some evidence suggesting the possibility of breeding in the state. The primary evidence for this is the relatively large number of summer (after 10 June) records from southwestern Colorado (Table 1). As is readily apparent, Montrose County dominates, particularly since 2006. Of particular importance in this vein is that the town of Nucla claims two of the West Slope’s most prolific and proficient birders as residents. Coen Dexter and Brenda Wright have reported Lesser Nighthawk from the Nu- Table 1. Records of Lesser Nighthawk accepted cla sewage ponds annually since by or circulating through the Colorado Bird Re- 2006. Though Nucla claims the cords Committee; records from southwestern lion’s share of recent reports of Colorado are shown in bold type. the species from southwestern # of Date Year Location County Colorado, two late-summer/ individuals early-fall reports from massively 11 Jun 1908 1 Hoehne Las Animas under-birded Dolores County 20 Jun 1987 1 Montrose Montrose suggest that low-elevation sec- 27 May 1988 1 Two Buttes Reservoir Baca 28 May 1990 3 Two Buttes Reservoir Baca tions of that county might pro- 24 May 1991 1 Clifton Mesa duce additional records, while 6 Jul 1992 1 Highline Reservoir Mesa a report currently making the 19 May 1995 1 Two Buttes Reservoir Baca rounds through the CBRC of 1 Jun 1995 1 Fort Collins Larimer 25 Jul 1995 1 Two Buttes Reservoir Baca three at Totten Reservoir, Mon- 10 Sep 1995 1 Fort Collins Larimer tezuma County, on 5 June 2014 8–10 May 1997 1 Lamar Prowers (S. Mlodinow, N. Moore) sug- 12–28 May 1997 1 Holbrook Reservoir Otero gests that an even wider chunk 11 Jun 1998 1 Clifton Mesa 9 May 1999 1 Lamar Prowers of low-elevation southwestern 16 Apr 2001 1 Vineland Pueblo Colorado might profitably be 3 May 2003 1 Neenoshe Reservoir Kiowa searched for the species. 14 Jul 2006 1 Dove Creek Dolores On the dark side, though, 16 Aug 2006 1 Dove Creek Dolores documentation of Lesser 2 Sep 2006 1 Nucla Montrose 25–28 May 2008 1 Chico Basin Ranch Pueblo Nighthawk from southwestern 8 Jun 2008 1 Nucla Montrose Colorao has been unfortunate- 6 May 2010 1 Mitchek Ranch Cheyenne ly spotty, with submission of 15 May 2010 1 Colorado City Pueblo details to the CBRC support- 29 May 2010 1 Boulder Boulder 30 May–16 Aug 2011 2 Nucla Montrose ing reports from Nucla coming 11 Aug 2011 1 Nucla Montrose from just three years prior to 22 Jun 2013 1 Adobe Creek Reservoir Kiowa 2014 (2006, 2008, 2011). Giv- 5 Jun 2014 3 Totten Reservoir Montezuma

Colorado Birds Spring 2016 Vol. 50 No. 2 123 en the recent surge in reports from Colorado, particularly southwestern Colora- do, it seems likely that Lesser Nighthawk occupies a much wider range than previously understood. However, more and better documentation provided to the CBRC is needed to best appreciate this phenomenon and for its acceptance by the birding and ornithological communities outside of Colorado. While nighthawks present a difficult identification problem, the difficulty is even greater in southwestern Colorado, where the local breeding race of Common Nighthawk is henryi (Bailey and Niedrach 1965), which exhibits a Lesser Nighthawk–like appearance, a subject tackled elsewhere in this issue (Leukering 2016b).

Acknowledgments I thank Steven G. Mlodinow and Christopher L. Wood for review of a previous draft of this essay.

Literature Cited Andrews, R. and R. Righter. 1992. Colorado Birds. Denver Museum of Natural History, Denver, CO. Bailey, A. M. and N. J. Niedrach. 1965. Birds of Colorado. Denver Museum of Natural History, Denver, CO. Brigham, R. M., J. Ng, R. G. Poulin, and S. D. Grindal. 2011. Common Nighthawk (Chordeiles minor). The Birds of North America Online (A. Poole, Editor). Cornell Lab of Ornithology, Ithaca, New York, USA. doi:10.2173/bna.213. eBird. 2016. eBird: Online database of bird distribution and abundance. eBird, Ithaca, New York, USA. www.ebird.org. Janos, M. and I. Prather. 1989. A second specimen record of Lesser Nighthawk (Chor- deiles acutipennis) from Colorado, with notes on its occurrence and identification. C.F.O. Journal 23:134–138. Kingery, H. (Editor). 1998. Colorado Breeding Bird Atlas. Colorado Bird Atlas Partner- ship and Colorado Division of Wildlife, Denver, CO. Latta, S. C., and M. E. Baltz. 2012. Lesser Nighthawk (Chordeiles acutipennis). The Birds of North America Online (A. Poole, Editor). Cornell Lab of Ornithology, Ithaca, New York, USA. doi:10.2173/bna.314. Leukering, T. 2016a. Colorado’s bird list, decadal species accumulation, and comments on the state’s 500th species. Colorado Birds 50:114–117. Leukering, T. 2016b. In the Scope: Lesser Nighthawk: Identification pitfalls. Colorado Birds 50:105–113. Sibley D. A. 2014. The Sibley Guide, 2nd edition. Alfred A. Knopf, New York, NY. Webb, B. and J. Reddall. 1989. Recent state record specimens of birds at the Denver Museum of Natural History. C.F.O. Journal 23:121–127. Wickersham, L. E. (Editor). 2016. The Second Colorado Breeding Bird Atlas. Colorado Bird Atlas Partnership and Colorado Parks and Wildlife, Denver, CO. In press.

Tony Leukering, 1 Pindo Palm St. W, Largo, FL 33770 ([email protected])

124 Colorado Birds Spring 2016 Vol. 50 No. 2 The Colorado Field Ornithologists’ Quarterly

Instructions for contributors to Colorado Birds

Colorado Birds is devoted to the field study of birds in Colorado. We invite you to submit articles of general or scientific interest for publication. Authors are encouraged to submit materials that contribute to the enjoyment and understanding of birds in Colo- rado. The preferred submission method is via email attachment to the Colorado Birds editor ([email protected]).

Photos or other art may be submitted in black and white or color. Files should be saved as high-resolution jpeg or similar format and must be a minimum of 900 x 750 pixels. Please DO NOT save photos in MS Word or otherwise embed within a document. Include photo captions along with the photographer’s name, where and when taken and other relevant information. All photos should be sent to the Colorado Birds editor, [email protected].

Submissions of photographs of birds observed in Colorado are welcome. Please include all relevant details including where and when the photo was taken and send to the Colorado Birds editor, [email protected].

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Colorado Birds Spring 2016 Vol. 50 No. 2 125 Fig. 1

Fig. 2

In the Scope Lesser Nighthawk: Identification Pitfalls . . . 105