Vol. 49 No. 3 Summer 2015 Colorado Birds The Colorado Field Ornithologists’ Quarterly

Mary Virginia Anderson Ravens and Colorado's Gunnison Sage-Grouse The Hungry Bird—Ticks! 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 cur- rent term. An asterisk indicates eligibility for re-election. Terms expire at the annual convention.a

Officers: President: Doug Faulkner, Arvada, 2017*, [email protected]; Vice Presi- dent: David Gillilan, Littleton, 2017*, [email protected]; Secretary: Larry Modesitt, Greenwood Village, 2016, [email protected]; Treasurer: Michael Kiessig, In- dian 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, Boulder, 2017*; Tony Leukering, Largo, Florida, 2017*; Bill Schmoker, Longmont, 2016; Glenn Walbek, Castle Rock, 2015

Colorado Birds Quarterly:

Editor: Peter Burke, [email protected]

Staff: Christy Carello, science editor, [email protected]; Christian Nunes, photo editor, [email protected]

Contributors: David Dowell, Dave Leatherman, Tony Leukering, Bill Schmoker

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

COPYRIGHT © 2015 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.

106 Colorado Birds Summer 2015 Vol. 49 No. 3 The Colorado Field Ornithologists’ Quarterly Vol. 49 No. 3 Summer 2015

PRESIDENT’S MESSAGE ...... 108 Doug Faulkner

ABOUT THE AUTHORS ...... 110

CFO BOARD MEETING MINUTES ...... 112 Larry Modesitt

MARY VIRGINIA ANDERSON ...... 115 Robert Righter

IN THE SCOPE: SOFT PARTS: LEG COLOR IN PASSERINES ...... 117 Tony Leukering

CFO FIELD TRIP ANNOUNCEMENTS ...... 119

FULLY EXPOSED: WORK THE SHOT ...... 120 Bill Schmoker

NEWS FROM THE FIELD: WINTER 2014–2015 ...... 124 David Dowell

THE HUNGRY BIRD: TICKS ...... 139 Dave Leatherman

COMMON RAVENS BENEFIT FROM HUMAN SUBSIDIES IN GUNNISON'S SAGEBRUSH SEA ...... 147 Patrick Magee Yellow-throated Warbler, Lamar, Prowers County, 12 May 2010. Photo by Glenn Walbek PRESIDENT’S MESSAGE

Collective Effort

Doug Faulkner My first memory of Colorado is as a teenager when my family vis- ited Denver for one of my dad’s Lions Club conventions. I remember seeing Mile High Stadium, attending a rodeo and getting in some high-elevation training for my upcoming Indiana high school cross- country season. That was 1988. I wouldn’t visit the state again until 1996 when Tony Leuker- ing and the Colorado (Rocky Mountain) Bird Observatory took a chance to hire this Midwest- ern birder to run a banding station in southwest Colorado. I spent three wonderful months living in Durango and the Dolores River SWA. Tony brought me back for another summer in 1997, this time running a banding station on the Grand Mesa. We kept in touch as I lived the life of a bird bum and eked out a U.S. Big Year win over him in 1998 with 504 species (I have a signed Sibley Guide as evidence of that momen- Doug Faulkner tous occasion.) I was surprised when Tony asked me to interview for a full-time biologist position. Short story is that I arrived full-time in Colorado in January 1999. I remember attending a Denver Field Ornithologists meeting shortly after arriving and being introduced to the crowd by Tony. Imagine my trepidation at suddenly having 50 sets of eyes sizing up the birding prowess of this Midwestern kid. Afterwards, Warren Finch greeted me and I have never felt so welcome. Warren had a way of making a stranger in a strange land feel like family. His kind does not grow on trees. The first CFO convention I attended was Grand Junction in 2000. I led an owling trip that included my future mother-in-law although at the time I had not yet met her daughter! And speaking of owling, Rich Levad was strongly influential during my early years in Colo- rado. We worked and birded western Colorado together throughout 1999 and 2000. I have fond memories of rafting the San Miguel River with him to count Black Phoebes, and of his unwavering enthusiasm for owls and Black Swifts. Even when I strayed into Wyoming for work, he crossed the border to help me with Purple Martin and Flam- mulated Owl surveys. A typical day for Rich included explaining the function of gerunds in the English language, doing the New York Times crossword and banding Long-eared Owl nestlings.

108 Colorado Birds Summer 2015 Vol. 49 No. 3 Over the next several years I became more involved in the Colo- rado birding community. Scott Gillihan, CFO’s journal editor, asked me to take over as editor in 2002. Before him, Cynthia Melcher had been the editor for years and I was concerned that I could not keep up the journal standards Cynthia and Scott had set. With Scott’s tutoring and help I took on the role and stayed with it through 2006. The journal’s name changed to Colorado Birds with the blessing of Bob Andrews and Bob Righter, and the Board financed more color cover photos. Still, that was a more rudimentary form of the journal than what you are reading now thanks to subsequent editors Nathan Pieplow and Peter Burke. I must confess that I did cheat on Colorado for a few years starting in 2004 while I worked for the University of Wyoming writing Birds of Wyoming. However, I continued to live in Colorado. Larry Semo inducted me into the Bird Records Committee in 2005 where I would serve two terms as a voting member and then as a non-voting Secre- tary. Larry’s sudden illness and quick passing in 2011 were dark days personally and for the CBRC. My decision to accept the CFO Board’s request that I serve CFO as its next CBRC Chair was not taken lightly. How could anyone replace Larry’s steel-trap memory, his attention to detail and the thoroughness with which he did his work? Impossible. Peter Gent’s steady guidance and advice were indispensable early on and throughout my term as Chair. My responsibilities would also have been more difficult without Rachel Hopper’s dedication as Secretary during my tenure. The vision for, and creation of, the CBRC and County Birding websites are as much hers as anyone else’s. This President’s Message was meant to introduce me to you, but I also wanted it to serve as a reminder that CFO is more than any one person or small group of individuals. The individuals I mentioned are just a few within CFO who have made this organization what it is today. I feel lucky to be associated with all of these names, and I look forward to getting to know those whom I have not yet met. Which brings me to the here-and-now. The CFO Board has asked that I serve as President. Not an easy task to follow the successes un- der the leadership of recent presidents Jim Beatty and Bill Kaempfer. I will work to the best of my abilities as president, as I did as journal editor and CBRC Chair. I suspect, however, that CFO’s continued success will result from the collective effort of all who share their time and skills. CFO is loaded with talent, both on and off its board, and I have no doubt that our organization is in good hands now and into the future.

Doug Faulkner, [email protected]

Colorado Birds Summer 2015 Vol. 49 No. 3 109 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 con- tributor 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.

110 Colorado Birds Summer 2015 Vol. 49 No. 3 Featured Authors

Mary Virginia Anderson 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.

Ravens Patrick Magee is a wildlife biologist at Western State Colorado University in Gunnison, Colorado, where he has worked for 18 years. He teaches a variety of courses and serves as Director of the Thornton Biology Undergraduate Research Program. He and his students, in collaboration with several outside agencies, have studied a variety of species, among them sagebrush obli- gate birds, piñon-juniper birds Gunnison Sage-Grouse, Com- mon Ravens and Red Fox. Patrick earned his B.S. in Wildlife Biology from Colorado State University and his M.S. and Ph.D. in Wildlife Ecology from the University of Missouri.

Colorado Birds Summer 2015 Vol. 49 No. 3 111 CFO BOARD MEETING MINUTES

18 April 2015 Center for Innovation and Creativity, Boulder, CO

Larry Modesitt President Bill Kaempfer called the April quarterly meeting to or- der at 11:07 A.M. Beginning the meeting on time remains a Presiden- tial challenge, as Bill noted that not even the constant drizzle dur- ing pre-meeting birding could reduce board members’ enthusiastic search for Boulder County rarities. Other officers present were Vice President Christian Nunes, Secretary Larry Modesitt and Treasurer Tom Wilberding. Directors Christy Carello, Lisa Edwards, David Gil- lilan, and Joe Roller also were present. Directors Peter Burke, Doug Faulkner, Mike Henwood, and Ted Floyd sent their regrets. In addi- tion, Michael Kiessig and Christie Owens attended as invited guests. Secretary’s Report: Larry Mode- artwork from Sherrie York that was sitt’s minutes of the 24 January 2015 used for the design of the Salida Con- board meeting were approved. vention T-shirts and a complete two- volume set of the Niedrach and Bailey Treasurer’s Report: Tom Wil- classic, Birds of Colorado, in excellent berding’s previously emailed financial condition. statements for the first quarter of 2015 4. Jeopbirdy. Christian Nunes an- were approved. nounced that this popular game will be played in teams. 2015 Salida Convention Plan- 5. Paper Sessions. Christy Carello ning—Bill Kaempfer reported that four people have already 1. Facilities. As of today’s date, registered to present papers. 203 people have registered, one less 6. T-shirts. Sherrie York contrib- than the record 204 from Trinidad. In uted the artwork and Lisa Edwards addition, we have raised $6,000 more announced the shirts will be ordered income, or 30 percent more than soon. Trinidad’s record. 7. Ask Me. Chris Owens indicated 2. Field Trips. Antero Reservoir that Lynne Miller and Michael Kies- will be drained this summer. We had sig will be on hand to help attendees hoped that extended mudflats would with locations, times and other types be outstanding for shorebirds. They of questions. Carpooling to the ban- probably will be there, but sadly we quet will be encouraged. will not, as the Denver Water Board recently announced that access will Future convention sites. The be closed on June 1. Consequently, we board discussed future sites. will choose alternates. 3. Banquet. We will have two si- Maintenance Contract for AJEn- lent Auction items, a print of the deavors—We agreed to offer AJE a

112 Colorado Birds Summer 2015 Vol. 49 No. 3 maintenance contract for all three mittee (CBRC)—Doug Faulkner websites for a total of $750 per year. submitted his report by email. Doug has started transitioning Chair re- Project Fund and Scholarships— sponsibilities to his successor, Mark Christy Carello reported that Tom Peterson. The committee has nearly Wilberding has sent checks to project completed its review of the submis- award winners and that no scholar- sions from the first quarter of 2014. In ship requests were received by the addition, Doug has reviewed approxi- deadline. mately 200 published records dating back to 1973 that had not yet been CFO-Western Field Ornitholo- uploaded into the CBRC database. gists (WFO) Partnership—Larry For those folks awaiting the history of Modesitt reported that WFO is in- the Great-tailed Grackle into Colo- terested in a joint CFO/WFO con- rado, your wait will be over as soon as vention in Colorado in 2017. CFO the records can be digitized. members who attend the WFO Con- vention June 10-14 in Billings, Mon- CFO Website—David Gillilan re- tana will receive the same rate as ported strong usage for our three web- WFO members. sites with cobirds.org averaging 160 visits per day, coloradocountybirding. Role of Conservation in the Mis- org averaging 138 visits per day and sion of CFO—Larry Modesitt moved coloradobirdrecords.org averaging 58 that “CFO establish a ‘Conserva- visits per day. Despite the high volume tion and Science Policy’ Committee, of usage, problems are rare. David sug- whose function would be to explore gested that AJEnterprises make some and evaluate means by which CFO enhancements after the convention. can most effectively engage with con- servation and science policy issues Social Media Communications — and maintain an awareness of devel- Christian Nunes reported 1055 Face- oping issues in which CFO might be book followers, with 291 on Twitter. involved.” In the ensuing discussion it Christian noted that the Cortez Cali- was agreed that there are many topics fornia Condor sighting was first publi- in which a committee’s consideration cized via Facebook, an indicator of how prior to issuing comments at large, or valuable this communications method in articles in Colorado Birds, might has become. He also suggested Lisa Ed- prove beneficial. The motion was ap- wards do some research to determine proved. Larry Modesitt agreed to chair how many new members came to CFO the committee, and Christy Carello via Facebook. also will participate. Other individuals not on the CFO Board will be sought Additional Committee Reports to contribute as well. 1. Colorado Birds—Peter Burke is noting on Cobirds that he welcomes Colorado Bird Records Com- articles for future editions. Peter also

Colorado Birds Summer 2015 Vol. 49 No. 3 113 is interested in selecting an intern will lead a NE CO trip August 29th or two to help with editing, “article and an overnight trip to Riverside chasing,” online content, and perhaps Reservoir August 22. Each day will digitizing archives. feature trips to a private ranch. 2. Publicity—Ted Floyd listed sev- eral field trips and events in which The board commended term-limit- he and others plugged CFO, as well ed Director Joe Roller who has been as numerous articles in our website, nominated to be the next President of www.Cobirds.org, and in Facebook. Denver Field Ornithologists. 3. Membership—Lisa Edwards re- ported we now have over 500 paying The next meeting will be at 11:00 members of Colorado Field Ornithol- at the Old Stone House at Barr Lake ogists. We’ve been increasing mem- State Park on September 12, 2015. bership by approximately 20 per year. 4. Nominating & Awards—Joe President Kaempfer adjourned the Roller made award recommendations, meeting at 2:08 P.M., possibly an early and they were accepted by the board. record for a pre-convention meeting. 5. CFO Field Trips—Bill Kaemp- The board was impressed with its ef- fer discussed the upcoming full SE ficiency. Colorado trip May 8. Mike Henwood will be leading a west slope trip on the Respectfully submitted, Uncompahgre Plateau in June. Bill Larry Modesitt, Secretary

114 Colorado Birds Summer 2015 Vol. 49 No. 3 Mary Virginia Anderson (1833–1912)

Bob Righter General Sherman’s decisive march through the Carolinas took place in the Civil War in 1864. Sherman surrounded the Fayette- ville Arsenal, an important Confederate munitions storage facility in North Carolina, and pounded it with devastating artillery barrages. Inside the arsenal the ground trembled from the effects of exploding shells fired from six-, 12- and 20-pound artillery cannons. The air was heavy with the odor of explosive residue. It would be just a matter of time before Sherman would walk through the gates of the arsenal demanding unconditional surrender from anyone who happened to still be alive. A pregnant Virginia Anderson was among the few to survive the assault trapped inside the arsenal. She had traveled from her home in South Carolina to visit her brother, the Confederate Command- ing Officer at the arsenal, Frederick Childs. Prior to the Civil War, General Sherman was well acquainted with both the Child and Anderson families. Desperate, Virginia managed to sneak a note to Sherman requesting safe conduct from the arsenal. In a rare moment of military compassion, Sherman granted Virginia’s request and thus she escaped an almost certain death from the siege. During the Civil War, it was not uncommon for families or relatives to find themselves opposing one another on the battle field. William Anderson, age 31, and Virginia Childs, age 22, were married prior to the Civil War in Wilmington, North Carolina on December 27, 1855. William was in the Army and shortly af- ter their wedding was ordered to New Mexico where he would be stationed at Fort Burgwyn, ten miles south of Taos. The fort was intended to protect the inhabitants of the Taos Valley from Apache and Ute Indian attacks. Virginia joined William, and insisted on bringing her piano. The Anderson family, piano and all, bumped its way westward along the Santa Fe Trail, which ran parallel to the Arkansas River. On the road to Taos they were looking forward to stopping at Bent’s Fort, near La Junta, Colorado, to re-stock their supplies and get fresh trail information about the route to New Mexico. The trip west was uneventful although the piano suffered from being tossed and shaken about on the rutted roads, and was soaked during a river crossing. During this era, Spencer Baird of the Smithsonian Muse- um in Washington D.C. kept a keen eye open for Army expeditions traveling west who might have officers willing to collect natural his-

Colorado Birds Summer 2015 Vol. 49 No. 3 115 tory specimens for the Museum. William was one of those officers recruited by Baird. Virginia and William had four children, born one after the other, during their stay at Fort Burgwyn. In addition to raising her children, Virginia entertained everyone at the Fort with her delightful singing and rhythmic piano playing. Meanwhile, William dutifully collected all the flora and fauna he could lay his hands on, and in 1858, Baird received a shipment that contained a specimen of a new warbler spe- cies along with a request that the bird be named after Virginia. Baird gladly complied. In the summer of 1860, William Anderson received orders to re- port to Texas where he would be stationed at Fork Clark and Fort Chadbourne. Not long after, on October 10, Baird received an- other box from Anderson, this one containing specimens collected in Texas, and among them was a special falcon. Baird wrote back to Anderson, “...among other specimens, one of the only species of hawk wanting to our collection, namely Falco femoralis, Aplomado Falcon.” Anderson’s specimen may have represented the first docu- mented North American record for this falcon. Before the Civil War, William was an officer in the United States Army. However, he later resigned, choosing to serve in the Confeder- ate Army, first as a surgeon and then later as Medical Inspector. After the War William and Virginia had four more children. Virginia was the organist at the nearby Episcopal Church near Santee Hills, South Carolina. She and William founded the Stateburg Literary and Musi- cal Society. One meeting reportedly started at ten in the morning and, with all the dancing and whooping it up, ended at midnight. Amazingly, the Society still flourishes to this day. Virginia and Wil- liam lived out their days surrounded by grandchildren in their house in Santee Hills. Theirs is a love story about staying together and en- during incredible hardships in their journey through life during the Civil War.

For further reading: Mearns, Barbara and Richard Mearns.1992. Audubon to Xantus. Academic Press, London and San Diego, CA

Bob Righter, [email protected]

116 Colorado Birds Summer 2015 Vol. 49 No. 3 IN THE SCOPE

Soft Parts: Leg Color in Passerines

Tony Leukering Most birders pay, perhaps, too much attention to plumage color and pattern when looking at birds. What separates the highly skilled birders from the rest of us is their keen knowledge of all the facets of a bird’s behavior and appearance. Soft-parts coloration is just one of those facets, but it is one that I’ve paid more and more attention to over the years, as I’ve found it very useful in bird identification. If you look at the back cover of this issue, what feature would you say this disparate set of passerines shares? Particularly alert readers may have arrived at the correct answer even without looking at “Soft parts” is the term given to the parts of a the title of this essay. The im- bird not covered by feathers, although some ages on the back cover include of these parts are not actually “soft.” For most a thrush, a pipit, two warblers species, the list of soft parts is limited to the and a sparrow. Bill shapes differ, size differs, primary projection bill, eyes and legs, but a sizable minority have differs and plumage color and additional features such as orbital rings or pattern certainly differ! The bare facial skin, even largely un-feathered only consistent feature (other heads. Many of us already use these features, than the basic fact that each at least half-heartedly, in bird identifcation. bird has two wings, two legs, a There are even species named for soft parts, tail, etc.) is that they all have pink legs. This is somewhat odd such as Yellow-billed Cuckoo, Red-eyed Vireo because pink legs is a rare fea- and Greater Yellowlegs. We are thus aware of ture in ABA-area bird species. the importance of the colors of these particu- The feature is quite rare in non- lar soft parts, at least on certain species. passerines (with the notable ex- ception of large, white-headed gulls) and is not all that common in passerines. Among passerines, the feature is most common among the em- berizid sparrows (family Emberizidae), not to be confused with the original passerid sparrows (Passeridae, such as House Sparrow). In fact, there may well be more pink-legged ABA-area emberizids than all other pink-legged ABA-area species combined, with some 34 of 44 New World-breeding emberizid species sporting pink or pinkish legs (Sibley 2014). So, how is it that pink legs are so useful as an identification char- acter if nearly all sparrows sport pink legs and nearly nothing else does? And particularly given that Catharus thrushes (e.g. Hermit Thrush, Fig. 1), Ovenbirds (Fig. 2) and waterthrushes, which are of-

Colorado Birds Summer 2015 Vol. 49 No. 3 117 ten mistaken for sparrows and vice-versa, also sport pink legs? I’m glad you asked! In Colorado, juvenile Horned Larks are frequently misidentified as Sprague’s Pipits (Leukering 2009). However, a quick look at the bird’s legs would point out that mistake, since Sprague’s Pipits (Fig. 3.) have pink legs, while Horned Larks have black legs. Indeed, the legs of most American Pipits are either black or dark, although some have pinkish legs. Of course, if the bird is posing for you nicely in the open in Colorado, almost by definition it is not a Sprague’s Pipit! Orange-crowned, Nashville and MacGillivray’s Warblers are another source of confusion for many birders. I even know of bird banders that have misidentified juvenile/immature Orange-crowned Warblers as MacGillivray’s Warblers. Yet only MacGillivray’s War- bler (Fig. 4) has pink legs, Orange-crowned and Nashville have black legs. Of course leg color won’t help you differentiate MacGillivray’s Warbler from Mourning Warbler or Common Yellowthroat as all three have pink legs! Our final example involves towhees. I believe that Canyon To- whee (Fig. 5) is often misidentified as Green-tailed Towhee in south- eastern Colorado during winter. Here again, if you know that Green- tailed Towhees have black legs, then it’s rather straight forward to separate these from the pink-legged Canyon Towhee. Thus a detailed knowledge of leg color is an important component of high-level field-identification skills. So get out your field guide and note all the passerines with pink legs. If you look carefully you may notice a strikingly obvious behavioral feature that seems highly cor- related with pink legs. Go ahead, I’ll wait! Well, did you figure it out? Pink-legged passerines, nearly to a spe- cies, spend much of their time on or near the ground. The mechanics of this correlation, that is, the reason or reasons behind it, are un- known to me and, it seems, unknown to science in general. At least none of the birders/ornithologists that I’ve asked have been able to provide an answer, nor have I been able to find an answer in the or- nithological literature. Still, even if we don’t know if, or what, links these pink-legged species, we can use the presence of pink legs to aid us in field identification.

LITERATURE CITED Leukering, Tony 2009. Juvenile Horned Lark. Colorado Birds 43:152-154. Sibley, David Allen 2014. The Sibley Guide to Birds, Second ed. Alfred A. Knopf, New York.

Tony Leukering, [email protected]

118 Colorado Birds Summer 2015 Vol. 49 No. 3 CFO Summer Field Trips

Riverside Reservoir August 22, 2015 Here is an unusual opportunity to visit the Riverside Reservoir in eastern Weld County, which is private and generally not open to the public. Join leaders Bill Kaempfer, John Vanderpoel and Skip Dines in visiting riparian areas below the dam as well as the extensive shoreline of the reservoir itself. Conditions at Riverside Reservoir of- ten produce extensive shorebird habitat even when other NE plains reservoirs are full to the brim. Expect to find migrant songbirds, shorebirds, raptors, gulls and terns. The trip will depart at 6:00 A.M. from the Park-and-Ride located at US 287 and Niwot Road. (Note that this is not the Niwot Park- and-Ride on CO 119!) Be sure to bring water, food for lunch and snacks, sun and insect protection. We will return by late afternoon. Please contact Bill Kaempfer ([email protected]) to reserve a spot on this trip.

NE Colorado Overnight—August 29–30 Join Bill Kaempfer and John Vanderpoel on the CFO’s Annual NE Colorado end-of-August trip. This trip is limited to 12 participants only. We will visit the large plains reservoirs on Saturday including Jackson, Prewitt and North Sterling. Sunday we will continue east to Sedgwick County and work our way back visiting the Pony Express Trail, Jumbo Reservoir, Red Lion and Tamarack SWAs. This trip of- fers excellent opportunities to find NE Colorado breeding specialties, eastern migrants and migrating shorebirds, raptors, sparrows, gulls and terns. Please contact Bill Kaempfer ([email protected]) to reserve a spot on this trip and for further information.

Colorado Birds Summer 2015 Vol. 49 No. 3 119 FULLY EXPOSED

Six Editing Tools Every Bird Photographer Should Know and Love

Bill Schmoker I like to remind participants in my bird photography workshops that the work isn’t over after taking a picture—editing is a critical component of the shot. There’s no question that I’d rather look at birds than at a computer screen. Yet I also know that virtually any picture I’ve shared or published benefitted from at least a wee bit of editing. So I try to strike a happy medium by doing simple, quick editing most of the time, usually less than a minute per photo. Much can be said about the pluses and minuses of advanced photo editing, and there are literally hundreds of books on the subject, so I won’t tackle that topic here. Whatever your level of expertise, I encourage all photographers to develop a philosophy or purpose behind your editing. I try to edit photos to most closely match what I observe in the field and thus espouse minimally invasive edits, but that’s just my style. I equally value the work of other photographers who employ advanced editing techniques to achieve their visions. A few notes before we dive in: UÊ ÊÕÃiÊAdobe Photoshop Elements, so my terminology comes from this program, but most photographic editing software has similar functions, though the names may vary. UÊ / ˆÃÊ>À̈ViʈÃʘœÌÊÜÀˆÌÌi˜Ê>ÃÊ>ÊÌÕ̜Àˆ>ÊLÕÌÊÀ>Ì iÀÊ>ÃÊ>˜Êˆ˜ÌÀœ`ÕV- tion to the world of “post processing.” My intention is to encourage experimentation with these and other editing tools. (You could also try Googling, how to use spot healing brush…) UÊ œÀÊ ˆ} iÃÌÊ µÕ>ˆÌÞÊ « œÌœÃÊ >˜`Ê ÌœÊ i˜>LiÊ >`Û>˜Vi`Ê i`ˆÌˆ˜}]Ê it’s necessary to shoot in RAW format. Doing so saves all the sensor data when you take a photo. However, RAW photos virtually always need more editing to look good so the tips below are targeted towards JPEGs. When cameras save JPEG files they are compressed to take up less space, but some original data is also lost. However, the camera also does significant initial post-processing for you when producing a JPEG. Both formats have advantages but in my case I work with high-quality JPEG files most of the time. UÊ
Ü>ÞÃÊÃ>ÛiÊޜÕÀÊ՘i`ˆÌi`ʜÀˆ}ˆ˜>ÃtÊ
˜`ÊL>VŽÊÌ i“ÊÕ«oޜÕÊ might want to return to these later. Many photographers, myself in- cluded, also back up their backups. Remember, there are just two kinds of photographers: those who have had a hard drive fail, and those who will!

120 Colorado Birds Summer 2015 Vol. 49 No. 3 UÊ Ê}i˜iÀ>ÞÊvœœÜÊÌ iʜÀ`iÀʜvʜ«iÀ>̈œ˜ÃʏˆÃÌi`ÊLiœÜ]ÊÜ ˆV Ê I’ve found creates an efficient workflow. I also suggest you use the preview windows and/or learn to use the undo and redo shortcuts. Toggling back and forth after making an adjustment can be a very useful way to decide if you’ve gone too far with your editing.

The Tools 1. Crop: Nearly every photograph I take gets at least a bit of crop- ping, and some are significantly cropped. How much cropping a photo can tolerate mainly depends on two factors: how many mega- pixels your sensor records to begin with and how much resolution you need for the final use. For emails, blog posts, Facebook, etc. you can get away with a lot more cropping than you can if you hope to be featured on the cover of Colorado Birds or want to make a large print. Cropping also can help you re-compose the picture, eliminate a distracting element from a side of the frame or tighten up on a bird that was too distant. 2. Spot Healing Brush: Ever reviewed your pictures and noticed a spot (or spots) consistently showing up in the same place? This likely means your sensor is in need of cleaning. But fear not, the Spot Healing Brush is a quick and easy way to get rid of these annoying flaws. The same thing (and much more) can be accomplished with the clone stamp tool if you don’t have a spot healing brush in your software, but it takes a few more steps to achieve the cleanup. 3. Noise Reduction: After a quick check to eliminate offending dust spots, I’ll determine if my image appears grainy, blotchy or dis- colored, which is to say, “noisy.” If things look good I’ll skip this step, but at high ISOs, shooting longer exposures in low light or when working with an old picture, this step can significantly improve the image quality. Generally speaking, cameras with smaller sensors, in- cluding most all-in-one cameras (sometimes called super-zoom or bridge cameras), generate noisier images. Most photo editing soft- ware programs include built-in noise reduction options, but I prefer NoiseWare, a plugin available from imagenomic.com. Once installed, this simple-to-use tool appears on the filters menu in Photoshop Ele- ments. I typically use the default setting, and one click later I’ve got a greatly cleaned-up image. 4. Adjust Lighting: If the original exposure is a bit off, adjusting the lighting often can improve the balance. My approach is first to adjust levels, moving the right (light) and left (dark) sliders to get the balance I’m after, though there is also a mid-tone slider. Over-adjust- ing lighting can look unnatural, but subtle changes can really help. For images with a lot of difference between light and dark areas, I

Colorado Birds Summer 2015 Vol. 49 No. 3 121 like to use the Lighten Shadows/Darken Highlights option, which offers a more dynamic range. In avian photography, this can be especially helpful if you’ve backlit or otherwise underexposed the subject…easy to do with a bright sky behind the bird. 5. Re-size Image: Unless you intend to print a picture, or send it for use in a publication, it is usually best to reduce the size of a picture before emailing it to pals or posting it online. You can re-size a photo simply by setting the widest pixel count (e.g. 1,000 pixels) or setting the measured dimensions (e.g. 12 inches wide) and by adjusting the dots per inch (dpi) to 72, which is sufficient for emails and blog posts. In Photoshop you can use the Save for Web option, which automati- cally optimizes the file size. I find that using this feature at quality 70 looks really good for online viewing and chops the file size down significantly. 6. Sharpening: This feature is easy to overuse, resulting in odd- looking pictures. However, sometimes a bit of sharpening can really finish off a picture well, particularly if the focus is a little soft, or when an image has been cropped hard. There are two ways to adjust sharpness. The easiest is to use Auto Sharpen, or you can manually set sharpness. Some software bundles the sharpness parameters and requires one to select the paradoxically named Unsharp Mask option in order to view the individual controls. So now you know my basic routine for post processing photo- graphs. I don’t necessarily make adjustments in every one of these areas for every photo I take. With practice you can learn to analyze your images according to these six steps in a minute or less. This is what I do most of the time for quick edits. Conversely, there are other really great tools in Photoshop and other editing programs that I use from time to time for more advanced work – but I’ll leave that for a future edition of Fully Exposed. Whatever the case, put a few quick editing tools into your main lineup and with minimal extra time you’ll see a marked improvement in your final results.

Bill Schmoker, [email protected]

122 Colorado Birds Summer 2015 Vol. 49 No. 3 I snapped this Townsend’s Solitaire out my back porch door on a chilly April morning in 2014. Light was low so the shot is at a fairly noisy ISO 1600 (especially noticeable in the dark portions of the background.) I also don’t really like the centered composition.

In about a minute I arrived at this improved (at least in my opinion) ver- sion—first cropped for composition, then Noiseware filter applied (default settings), then minor level adjustment and a bit of shadow lightening. If I was posting this to Facebook or using it in a blog post I would have finished by re-sizing the pic to about 1000 pixels wide, but for publication I kept all of the remaining pixels.

Colorado Birds Summer 2015 Vol. 49 No. 3 123 NEWS FROM THE FIELD

Winter 2014–2015 (December–February)

David Dowell “News from the Field” contains reports of rare birds found in Colorado. These reports are compiled from the COBirds listserv ([email protected]), eBird (ebird.org) 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 documen- tation. Please submit your sightings of these “review” species through the CFO website at coloradobirdrecords.org.

Overview of the Season Three very cold periods in a winter that was otherwise not so harsh influenced the birding significantly during the December – February period. Cold and snowy weather in mid-November resulted in great movements of land and water birds and affected bird distri- butions in December. Very cold weather arrived again in late De- cember and early January, causing most lakes to become ice-covered quickly statewide. Christmas Bird Counters won’t soon forget birding in below-zero temperatures, but nevertheless they compiled some im- pressive species lists. Following milder conditions from mid-January into February, cold and snowy weather returned to Colorado again in late February. Colorado birders will particularly remember two rare birds during the winter of 2014-2015. First, many birders enjoyed excellent views of a juvenile Yellow-billed Loon in mid December, either where it was first found by Steve Mlodinow at Boyd Lake SP (Larimer) or where it was re-found by Joey Kellner at Chatfield SP (Douglas and Jefferson). A second rare bird that provided good views to patient birders was an American Woodcock found by Fawn Simonds at Bobcat Ridge Natural Area (Larimer) on 15 Jan and remaining at the same location for another 10 days. In the previous issue (Spring 2015) of Colorado Birds, Dave Leatherman discussed that woodcock’s attraction to a small stream in the foothills of northern Colorado. The Colorado Bird Records Committee has accepted 25 previous records of Yellow- billed Loon and 13 American Woodcock sightings. Perhaps related to the brief periods of extremely cold weather, or perhaps not, unusual finds of Pine Grosbeaks and Gray-crowned

124 Colorado Birds Summer 2015 Vol. 49 No. 3 Rosy-Finches at low elevations occurred in northern Colorado coun- ties Boulder, Jefferson and Weld. Colorado birders also found a surpris- ing number of species overwintering unusually far north, including Yellow-breasted Chat, Orange-crowned Warbler and Indigo Bunting as well as Cassin’s, Chipping, Brewer’s, Field, Vesper, Lark, Savan- nah, and Fox Sparrows. This summary wouldn’t be complete without mention of an ea- ger Colorado birder who reported “news from the field” throughout 2014. Exploring much of the state in his quest for a variety of birds, Glenn Walbek documented 386 different species during the year! Excellent photos of many of these birds can be seen on his photo website pbase.com/gwalbek/2014_birds. In the list of reports below, county names are italicized, and the fol- lowing abbreviations are used: CBC – Christmas Bird Count; CFO – Colorado Field Ornithologists; m. ob. – many observers; NM – Na- tional Monument; NWR – National Wildlife Refuge; Res. – Reser- voir; SP – State Park; SWA – State Wildlife Area.

Greater White-fronted Goose: Ranch, Pueblo, 2 Dec (JD, SaF). Five As many as 16 in Montrose, Mon- at Yampavian Ranch near Hayden, trose, 10 – 24 Jan (JH, BH, RH). 2 Routt, 4 Jan and 14 Feb (NaM). One south of Durango, La Plata, 19 Jan in Pueblo area, Pueblo, 24 – 25 Jan – 16 Feb (BWo, JBe, RMo). Uncom- (MP, BSt, DT, JD). As many as 20 at mon in western Colorado. 835 at Pre- Browns Park NWR, Moffat, 24 Jan – witt Res., Washington, 21 Feb (DD). 12 Feb (JL, T&DM). One at Holcim Trumpeter Swan: 1 at Chico Basin Wetlands, Fremont, 17 Feb (RM). Tundra Swan: Reports from Boul- der, Fremont, Larimer, Mesa, Park and Pueblo. EURASIAN WIGEON: Possible adult male at Barr Lake SP, Adams, 21 Jan (AHo). Adult male in Cañon City, Fremont, 25 Jan (JD). AMERICAN BLACK DUCK: one at Windsor Res., Weld, 13 Feb (SM, GD, DWa). Surf Scoter: two at Memorial Park in Colorado Springs, El Paso, 17 Nov – 6 Dec (BC, RiT, JD, SFa, TyS, m.ob.). Singles in Cañon City, Fre- “minima” Cackling Goose, Utah Park, mont, 17 Nov and 13 Dec (RM, DA). Aurora, Arapahoe County, 8 Decem- Black Scoter: one at Memorial ber 2014. Photo by Cathy Sheeter Park in Colorado Springs, El Paso, 7

Colorado Birds Summer 2015 Vol. 49 No. 3 125 Trumpeter Swans, Steamboat Springs, Routt County, 12 February 2014. Photo by David Moulton

Nov – 5 Dec (BC, m. ob.). Three ju- Long-tailed Duck: As many as 4 veniles at Rifle Gap Res., Garfield, 14 at Cherry Creek SP, Arapahoe, 1 – Nov – 13 Dec (D&MV, m.ob.). 25 Dec (S<, AHo, GW, m.ob.). White-winged Scoter: two at Big Singles at Windsor Lake, Weld, 3 Dec Johnson Res., El Paso, 14 Nov – (NL) and 16 Feb into Mar (AHe, NK, 20 Dec (AD, BiM, JD, LL, JoL, CJ, m. ob.). One at Big Johnson Res., El m.ob.). One at Cherry Creek SP, Paso, 6 – 12 Dec (MP, JD). One at Arapahoe, 21 Nov – 25 Dec (CM, Chatfield SP, Douglas, 8 Dec (DSu). GW, m. ob.). One at various locations One at Elevenmile Res., Park, 9 Dec near Longmont, Boulder, 17 – 24 Dec (DSu). One at Lathrop SP, Huerfano, (DD, SR, AC). One at Memorial Park 10 Dec (RM). One at Lake Trinidad in Colorado Springs, El Paso, 23 – 24 SP, Las Animas, 11 Dec (RM). One Dec (DA, NM). One during Loveland at Horseshoe Res., Larimer, 11 Dec CBC, Larimer, 1 Jan (CWi). One at (GD, KP, AHe, DWa, AB). Two at Pueblo Res., Pueblo, 2 Dec – 2 Feb North Sterling Res., Logan, 16 Dec (BP, m. ob.). One at Lake Minnequa, (GM, WK). As many as 3 at Pueblo Pueblo, 6 – 8 Feb (NE, LK, GW, BP, Res., Pueblo, 29 Dec – 7 Feb (BP, m. LeB, m.ob.). ob.). One near Durango, La Plata, 31

126 Colorado Birds Summer 2015 Vol. 49 No. 3 Red-necked Grebe, Arkansas River-Valco American Woodcock, Bobcat Ridge Nat- Ponds, Lamar, Prowers County, 5 Decem- ural Area, Larimer County, 17 January ber 2014. Photo by Janeal Thompson 2015. Photo by Tom Benfield

Jan (AWa). One at Lake Minnequa, tion, Mesa, 14 Dec (RWh). Rare in Pueblo, 8 – 11 Feb (MC, VB, m.ob.). western Colorado in winter. One at Mt. Elbert Forebay, Lake, 19 Green Heron: one at Sells Lake in Feb (VT, CP). One at Windsor Lake, Cañon City, Fremont, 21 Dec (RM, Weld, 16 Feb (AHe). One female near BP, CK); no prior winter records in Whitewater, Mesa, 28 Feb (BW, CD). Colorado on ebird. Red-throated Loon: one at Pueblo Merlin (Black): one in Grand Res., Pueblo, 29 Dec – 14 Feb (BP, Junction, Mesa, 28 Dec and 8 Jan m.ob.). (MH, KB). YELLOW-BILLED LOON: one BLACK VULTURE: one near juvenile at Boyd Lake SP, Larimer, Highway 34 (Riverside Res. area), 10 – 11 Dec (SM, m.ob.). One juve- Weld, 10 Nov (GR). nile at Chatfield SP, Douglas and Jef- California Condor: one, possibly ferson, 13 – 27 Dec (JK, m.ob.); seen 2, near Paonia, Delta, 12 – 15 Jan (re- previously at Boyd Lake. port relayed by JaB). Red-necked Grebe: one at North Sora: one in Grand Junction, Gateway Park in Lamar, Prowers Mesa, 14 Dec (RW, MH, KM, SR). (probably a first county record), 15 One at Fort Lyon Wildlife Easement, Nov – 14 Dec (JTh, JS, DR, SR, TD, Bent, 15 Dec (BP). One at Bear Creek BP). Other reports from Douglas, Greenbelt, Jefferson, 20 Dec (MH, Huerfano, Jefferson, Larimer, and PG). Two near Pueblo, Pueblo, 23 Pueblo. Dec (MP). One at Fountain Creek Double-crested Cormorant: one Regional Park, El Paso, 4 Jan (RH). at Blue Mesa Res., Gunnison, 6 Dec Rare in winter. (ARe, JH). One in Delta, Delta, 14 Spotted Sandpiper: 1 in Grand Dec (JaB, AS). Five in Grand Junc- Junction, Mesa, 3 Dec (MH). 2 in

Colorado Birds Summer 2015 Vol. 49 No. 3 127 Grand Junction, Mesa, 14 Dec (JTr, SBo). One at Pueblo Res., Pueblo, 1 RWh). 1 in Glenwood Springs, Gar- Feb (GM). One adult at Barr Lake SP, field, 23 Dec (JAR). Rare in winter. Adams, 4 Feb (DD). Greater Yellowlegs: one at Barr GLAUCOUS-WINGED GULL: Lake SP, Adams, 2 – 16 Dec and one juvenile at Larimer County Land- 27 Jan (DD, ML, LB, DRh). One at fill, Larimer, 1 Dec (SM). One ju- Chatfield SP, Jefferson, 7 Dec (JH). venile at Aurora Res., Arapahoe, 13 One at Walden & Sawhill Ponds, – 27 Jan (DD, DA, GM, AHo). One Boulder, 7 Dec (AMH). Two at Lake second year at Aurora Res., Arapa- Holbrook, Otero, 16 Dec (MP). One hoe, 23 Jan (GW). One juvenile at near Rocky Ford, Otero, 16 Dec Barr Lake SP, Adams, 5 Feb (DD). (DN). One at Parker Regional Park, One second-year at Barr Lake SP, Ad- Douglas, 20 – 21 Dec (TR). One near ams, 8 Feb (MP). Fort Morgan, Morgan, 21 Dec (DD). Herring × Glaucous-winged Gull: One in Commerce City, Adams, 8 As many as 4 (2 adults and 2 juve- Jan (DD). Two at Neesopah Res., niles) at Larimer County Landfill, Kiowa, 7 Feb (JTh). One at Walden Larimer, 1 – 24 Dec (SM, m. ob.). & Sawhill Ponds, Boulder, 7 – 8 Feb One subadult at Lagerman Res., Boul- (PB, m.ob.). One in Platteville, Weld, der, 17 Dec (SM). One juvenile at 26 Feb (NM, SM). This species over- Aurora Res., Arapahoe, 13 Jan (DD). winters in Colorado in small numbers. One juvenile at Pueblo Res., Pueblo, Dunlin: one along South Platte 25 Jan (JD). One juvenile at Barr Lake River near Thornton, Adams, 28 Feb SP, Adams, 5 Feb (DD). One juvenile continuing into March (Da, m.ob.). at Prewitt Res., Washington, 15 – 21 AMERICAN WOODCOCK: Feb (SM, BT, DD, m.ob.). One at Bobcat Ridge Natural Area, Glaucous Gull: Reports from Ad- Larimer, 15 – 26 Jan (FS, m.ob.). ams, Arapahoe, El Paso, Jefferson, Black-legged Kittiwake: one ju- Larimer, Morgan, Pueblo and Wash- venile at Pueblo Res., Pueblo, 9 Dec ington. (BP). Great Black-backed Gull: one Mew Gull: Reports from Adams, adult (plus 1 juvenile on 7 Feb) at Arapahoe, Denver, El Paso, Jeffer- Pueblo Res., Pueblo, 17 Nov - 15 Feb son, Larimer and Pueblo. (BP, m.ob.). ICELAND GULL: one and then Band-tailed Pigeon: one in Green 2 adults at Larimer County Landfill, Mountain Falls, Teller, 16 Jan – 7 Feb Larimer, 1 – 22 Dec (SM, NK, ScR, (RB, LHo). DWa, GD, MW, SW). One juvenile Western Screech-Owl: 99 in at Sixmile Res., Boulder, 1 Dec (DD). Grand Junction, Mesa, 15 Dec (team One juvenile Iceland and 1 adult effort coordinated by NKor). Iceland/Thayer’s at Horseshoe Lake, Burrowing Owl: one near Denver Larimer, 7 Dec (NK, SBa). One sec- International Airport, Denver, 18 Feb ond-year at Lagerman Res., Boulder, (RMa); very early arrival. 17 – 21 Dec (DD, DaW, SM, MCl, COSTA’S HUMMINGBIRD:

128 Colorado Birds Summer 2015 Vol. 49 No. 3 one adult female in Grand Junction, erwalk, Fremont, 21 Dec – 11 Jan (BP, Mesa, 1 Nov – 28 Dec, banded on 6 CK, RC, GW, MP). One in Florence Nov (L&TC, SB, m.ob.). River Park, Fremont, 10 Jan – 6 Feb Red-headed Woodpecker: one ju- (JK, m.ob.). venile in Florence, Fremont, 4 Dec Eastern Phoebe: one at Pueblo (RM); rare in winter. Res., Pueblo, 13 – 20 Dec (anony- ACORN WOODPECKER: one mous, DM); very rare in winter. adult female in Colorado Springs, El Say’s Phoebe: seven in Grand Paso, 20 Dec continuing into Mar Junction, Mesa, 14 Dec (RWh). (MWo, m.ob.). As many as 2 in Pueb- Tree Swallow: one at Teller Farm lo Mountain Park near Beulah, Pueb- and Lakes, Boulder, 15 Feb (CK); lo, 3 – 18 Jan (LE, VT, BP, m.ob.); early migrant. probable year-round residents. Rock Wren: eleven in Grand Red-naped Sapsucker: one in Junction, Mesa, 14 Dec (RWh). Grand Junction, Mesa, 4 Jan (LS). House Wren: one at Highline One in Durango, La Plata, 7 Jan – 9 Lake SP, Mesa, 31 Dec, (JC); very rare Feb (KD, RMo, BWo, AK). One at in winter. San Juan River bridge, Montezuma, PACIFIC WREN: one at Cañon 22 Jan (BWo). Rare in winter. City Riverwalk, Fremont, 21 Dec – 11 Yellow-bellied Sapsucker: one Jan (BP, CK, m.ob.). in Littleton, Jefferson, 7 Dec and 14 Winter Wren: Reports from Ad- Feb (JSh). Two in Willow Creek Park ams, Baca, Boulder, Douglas, El in Lamar, Prowers, 8 Dec – 25 Feb Paso, Fremont, Morgan, Otero and (DL, m.ob.). One male in Colorado Pueblo. Springs, El Paso, 20 Dec (CL). One Blue-gray Gnatcatcher: three at Pueblo City Park, Pueblo, 20 Dec in Grand Junction, Mesa, 14 Dec – 7 Feb (JD, m.ob.). As many as 2 in (RWh). One in Delta, Delta, 14 Dec Rouse Park in Cañon City, Fremont, (AS). Rare in winter. 21 Dec – 25 Jan (BP, CK, m.ob.). One Golden-crowned Kinglet: one at in Cañon City, Fremont, 4 Jan (MP). Las Animas Cemetery, Bent, 7 Dec One at Brush Hollow Res., Fremont, (DD). Four in Cottonwood Canyon, 19 Jan (KG, SBo, MCl). One at Lake- Baca, 10 Dec (JTh). One during John side Cemetery in Cañon City, Fre- Martin Res. CBC, Bent, 15 Dec (DN). mont, 17 Feb (RM). One at Lamar Community College, Black Phoebe: As many as 3 in Prowers, 3 – 20 Feb (DR, TF). Two at Grand Junction, Mesa, 14 Dec – 10 Eaton Cemetery, Weld, 28 Feb (FS). Feb (DeS, KM, MH, RW, SR, JTr, Rare on the plains. LS, KB); Black Phoebes previously Varied Thrush: one near Bailey, overwintered in the same area in Park, 2 Dec (DSu). One in West 2011-2012. One in Pueblo, Pueblo, Colorado Springs, El Paso, 2 – 4 Dec 12 Dec (VT). One in Colorado River (DRu). SP near Fruita, Mesa, 27 Dec and 1 Gray Catbird: one in Colorado Feb (BWa). One at Cañon City Riv- City, Pueblo, 2 Dec (DaS). Two at

Colorado Birds Summer 2015 Vol. 49 No. 3 129 Jackson Lake SP, Morgan, 21 Dec Tamarack Ranch SWA, Logan, 3 Jan (DD). One at Banner Lakes SWA, and 21 Feb (SL, LK, GW, DD); pos- Weld, 24 Feb (CS). This species over- sibly a hybrid with Spotted Towhee. winters in Colorado in very small Cassin’s Sparrow: two along numbers. County Road 215, La Plata, 18 Jan Snow Bunting: two at North Ster- (RMo); no prior winter records in ling Res., Logan, 13 Dec (GM, WK). Colorado. One near Spinney Mountain Res., Chipping Sparrow: one during Park, 16 Dec (DSu). Three near Riv- Mesa CBC, Mesa, 1 Jan (RWh, RL); erside Res., Weld, 31 Dec (SMa). One rare in winter. near Denver International Airport, Brewer’s Sparrow: one in Paonia, Adams, 2 Jan (LK). One during Raw- Mesa, 4 Dec (JaB); rare in winter. hide Power Station CBC, Larimer, 3 Field Sparrow: one at Bonny Jan (DKi). Two in northern Weld, 4 Jan SWA, Yuma, 27 Dec (GW, MP); rare (SM). One near Deer Trail, Arapahoe, in winter. 5 Jan (DSu). One at Rocky Mountain Vesper Sparrow: two during Mesa Arsenal NWR, Adams, 25 Jan (JO). CBC, Mesa, 1 Jan (RWh); rare in Orange-crowned Warbler: two in winter. Grand Junction, Mesa, 14 Dec (RW, Lark Sparrow: one in La Veta, DeS, KM, MH, SR); very rare in win- Huerfano, 26 – 27 Dec (P&PWN). ter. Several near Monte Vista NWR, Rio Pine Warbler: one at Denver West Grande, 9 Feb (VS). eBird shows no Office Park, Jefferson, 30 Nov – 14 prior winter records in Colorado. Feb (MC, m.ob.). One in Louisville, Sagebrush Sparrow: three in Nu- Boulder, 6 Dec (JTu). One at Fort cla, Montrose, 19 Feb (CD, BW). Lyon, Bent, 15 Dec (BP). One at Ru- One in Durango, La Plata, 24 Feb nyon Lake, Pueblo, 23 Dec (BP). (AmD). Early spring migrants. Yellow-breasted Chat: one near Savannah Sparrow: one at Lake Carbondale, Garfield, 11 – 15 Dec Minnequa, Pueblo, 1 Feb (MP); rare (DF, AL, JAR). One during Gunnison in winter. CBC, Gunnison, 14 Dec (AA). eBird Fox Sparrow (Red): one at Red shows no prior winter records in Colo- Rocks Park, Jefferson, 14 Nov – 6 Dec rado. (TM, m.ob.). One at Chatfield SP, Green-tailed Towhee: one in Douglas, 20 Dec – 10 Feb (JK, AHo, Steamboat Springs, Routt, 18 – 20 BoS, GW, LK, KMD, DSu). One in Dec (T&DM). One at Frederick Rec. Ken Caryl, Jefferson, 26 Dec (DSu). Area, Weld, 25 Dec (SM). Overwin- One in Littleton, Jefferson, 30 Dec – tering Green-tailed Towhees have 1 Jan (DKi, MG). been reported in Colorado in four of Fox Sparrow (Slate-colored): one the last 10 winters. altivagans at Cañon City Riverwalk, EASTERN TOWHEE: one male Fremont, 16 – 20 Jan (GW, MP, MC). at Marshall Mesa, Boulder, 15 Dec One at Lone Dome SWA, Dolores, 7 (anonymous). One first-year male at Feb (RMo, AmD).

130 Colorado Birds Summer 2015 Vol. 49 No. 3 Fox Sparrow: one during Durango northern part of Chatfield SP, Doug- CBC, La Plata, 14 Dec (SA). One in las, 20 Dec (RC, JK, AHo, BoS). As Boulder, Boulder, 23 Dec (TH). many as 2 at Adobe Creek Res., Bent, Golden-crowned Sparrow: one 2 – 24 Jan (DN, JTh). One at Two adult, returning for its fifth consecu- Buttes SWA, Baca, 6 Jan (JTh, DL) tive winter, at Teller Farm and Lakes, and 21 Feb (TF). Six in Florence, Fre- Boulder, 30 Oct continuing into April mont, 15 Feb (MP). Nine near Long- (DD, m.ob.). One adult, returning for mont, Weld, 22 Feb (SM). its sixth winter, at Red Rocks Park, Rosy-Finch sp.: 2500+ at Dino- Jefferson, 1 Nov – 8 Mar (CyJ, m.ob.). saur NM, Moffat, 6 Dec (BWa). Western Tanager: one near Du- Gray-crowned Rosy-Finch: 57 rango, La Plata, 1 Dec (AmD). One tallied over multiple locations in at Roxborough SP, Douglas, 4 Dec northern Weld, 4 Jan (NM, SM); rare (JHy). eBird indicates only one prior so far east of the mountains. winter record in Colorado. PURPLE FINCH: one female in Indigo Bunting: one in Rocky Steamboat Springs, Routt, occasion- Ford, Otero, 15 Dec (DN, SO); very ally from 23 Nov – 27 Dec (T&DM). rare in winter. This species is very rare in western Rusty Blackbird: six along Plum Colorado, and the sighting provides Creek upstream of Chatfield SP, a first county record. One adult male Douglas, 20 Dec (NE). Six or more in in Greeley, Weld, 12 Dec (SM). One female at Rocky Ford SWA, Otero, 16 Dec (BP). One west of Longmont, Boulder, 20 Dec (TD). One female in Livermore, Larimer, 3 Jan (NK, GD, DBr, AHe). One immature male in Lamar, Prowers, occasionally from 4 – 28 Jan (DL, JTh, DR, JS). One female in Las Animas, Bent, occasionally from 9 Jan – 28 Feb (DN). White-winged Crossbill: As many as 6 in Smith Park in Boulder, Boulder, 7 – 10 Dec (WK, PH). Four in Alma, Park, 9 Jan (DSu). 3 south of Lake George, Park, 16 Jan (DSu). Common Redpoll: one at Pueblo Res., Pueblo, 1 Dec (BP). 2 in Gree- ley, Weld, 27 Dec (DKi, GMa, MA, GL). One near Golden, Jefferson, 11 Jan (BoS). Eight at Loomiller Park in Purple Finch, Steamboat Springs, Routt Longmont, Boulder, 25 Jan (TF). Four County, 27 December 2014. Photo by in Steamboat Springs, Routt, 16 Feb David Moulton (DaB).

Colorado Birds Summer 2015 Vol. 49 No. 3 131 White-fronted x Cackling Goose, Utah Park, Aurora, Arapahoe County, 8 December 2014. Photo by Cathy Sheeter

Yellow-billed Loon with a Common Red-throated Loon, Pueblo Reservoir, Loon, Chatfield Reservoir State Park, Pueblo County, 5 February 2015. Douglas County, 15 December 2014. Photo by Bill Maynard Photo by Kathy Mihm Dunning

132 Colorado Birds Summer 2015 Vol. 49 No. 3 Glaucous Gull, Windsor Lake, Weld County, 13 March 2015. Photo by Dave Leatherman

Greater Yellowlegs, Neesopah Lake, Ki- Lesser Black-backed Gull, Windsor owa County, 7 February 2015. Photo Lake, Weld County, 9 March 2015. by Janeal Thompson Photo by Dave Leatherman

Colorado Birds Summer 2015 Vol. 49 No. 3 133 Greater Roadrunner, M & S May Valley Road, Lamar, Prowers County, 6 February 2015. Photo by Janeal Thompson

Short-eared Owl, Buckey Road, Larimer Acorn Woodpecker, Cheyenne Canyon, County, 22 February 2015. Photo by El Paso County, 5 January 2015. Photo Dave Leatherman by Bill Maynard

134 Colorado Birds Summer 2015 Vol. 49 No. 3 Yellow-bellied Sapsucker, Willow Creek Hairy Woodpecker, Boulder County, 20 Park, Lamar County, 9 January 2015. February 2015. Photo by Jane Baryames Photo by Janeal Thompson

Prairie Falcon, east of Lamar, Prowers Varied Thrush, Rudin residence, El Paso County, 12 February 2015. Photo by County, 4 December 2014. Photo by Dave Leatherman Bill Maynard

Colorado Birds Summer 2015 Vol. 49 No. 3 135 Yellow-rumped Warbler, Willow Valley Cedar Waxwing, Boulder County, 27 Drive, Larmar, Prowers County, 2 Decem- February 2015. Photo by Jane Baryames ber 2014. Photo by Janeal Thompson

Dark-eyed Junco (Cassiar’s) Willow Valley, Lamar, Prowers County, 14 December 2014. Photo by Janeal Thompson

136 Colorado Birds Summer 2015 Vol. 49 No. 3 Pine Grosbeak, Moose Visitor Center, Jackson County, 16 February 2015. Photo by Dave Leatherman

Herpburn’s Gray-crowned Rosy-Finch, Moose Visitor Center, Jackson County, 16 February 2015. Photo by Dave Leatherman

Colorado Birds Summer 2015 Vol. 49 No. 3 137 ACKNOWLEDGMENTS Contributions from the volunteer compilers are greatly appreciated: Jim Beatty (south- west), Coen Dexter (west), John Drummond (southeast), Forrest Luke (northwest), Brandon Percival (CBC), and Dave Silverman (south).

CONTRIBUTING OBSERVERS DA: Dale Adams, SA: Susan Allerton, MA: Mark Amershek, AA: Arden Anderson, AB: Andy Bankert, SBa: Scott Baron, JaB: Jason Beason, JBe: James Beatty, SBo: Su- san Bonfiglio, SB: Steve Bouricius, DBr: Denise Bretting, LeB: Leon Bright, LB: Linda Broeren, DaB: Dave Brotherton, VB: Vaughn Browne, RB: Richard Bunn, PB: Peter Burke, KB: Katey Buster, RC: Renee Casias, MC: Mark Chavez, AC: Al Clark, MCl: Matt Clark, L&TC: Larry & Twanna Cooksey, JC: Jacob Cooper, BC: Bob Craven, Da: Davis, TD: Todd Deininger, CD: Coen Dexter, DD: David Dowell, AmD: Amy Dobbins, GD: Georgia Doyle, KD: Kristi Dranginis, AD: Aaron Driscoll, JD: John Drummond, LE: Lisa Edwards, NE: Norman Erthal, SaF: Sandra Farkas, SFa: Sam Fason, DF: Dick Filby, TF: Ted Floyd, PG: Patti Galli, KG: Karen Goetz, MG: Mackenzie Goldthwait, AMH: Amanda & Matt H, RH: Rick Harner, BH: Bill Harris, TH: Thomas Heinrich, PH: Philip Henson, MH: Mike Henwood, AHe: Austin Hess, LHo: Linda Hodges, AHo: Alec Hopping, JH: Jon Horn, JHy: Jennifer Hyypio, CyJ: Cyndy Johnson, CJ: Clark Jones, WK: William Kaempfer, AK: Aaron Keller, JK: Joey Kellner, DKi: Doug Kibbe, LK: Loch Kilpatrick, CK: Chris Knight, NK: Nick Komar, NKor: Nick Korte, JoL: Joy Lake, LL: Leonard Lake, RL: Ron Lambeth, ML: Michael Lanzone, SL: Steve Larson, DL: Dave Leatherman, CL: Cecile Lee, GL: Gary Lefko, JL: Jan Leonard, AL: Al Le- vantin, NL: Norm Lewis, CM: Cynthia Madsen, SMa: Scott Manwaring, RMa: Robert Martinez, GMa: George Mayfield, BiM: Bill Maynard, DM: Dan Maynard, KM: Kath- leen McGinley, NaM: Nancy Merrill, KMD: Kathy Mihm Dunning, RM: Rich Miller, TM: Tim Mitzen, SM: Steve Mlodinow, GM: Gwen Moore, NM: Nick Moore, RMo: Riley Morris, T&DM: Tresa & David Moulton, P&PN: Paul & Polly Wren Neldner, DN: Duane Nelson, SO: Stanley Oswald, JO: Jen Ottinger, KP: Ken Pals, BP: Brandon Percival, MP: Mark Peterson, CP: Cody Porter, ScR: Scott Rashid, ARe: Alan Reed, DRh: David Rhoades, SR: Sue Riffe, JAR: JoAnn Riggle, DRu: David Rudin, DR: Doro- thy Russell, GR: Gene Rutherford, TR: Tim Ryan, LS: Laurie S., AS: Amy Seglund, CS: Cathy Sheeter, JSh: Janet Shin, DaS: Dave Silverman, VS: Virginia Simmons, FS: Fawn Simonds, BoS: Bob Spencer, DeS: Deb Stegall, BSt: Brad Steger, LS: Lee Stigen, TyS: Tyler Stuart, JS: Jane Stulp, DSu: David Suddjian, RiT: Richard Taylor, S<: Scott and Linda Terrill, JTh: Janeal Thompson, DT: David Tønnessen, JTr: Jackson Trappett, VT: Van Truan, JTu: John Tumasonis, BT: Bill Tweit, D&MV: Denise & Mark Vollmar, DWa: David Wade, GW: Glenn Walbek, BWa: Brett Walker, MW: Meghan Walters, SW: Sean Walters, AWa: Aimee Way, RWh: Robert Whitmore, CWi: Cole Wild, MWo: Marty Wolf, BWo: Beth Wolff, RW: Ronda Woodward, BW: Brenda Wright.CWi: Cole Wild, MWo: Marty Wolf, BWo: Beth Wolff, RW: Ronda Woodward, BW: Brenda Wright.

David Dowell, [email protected]

138 Colorado Birds Summer 2015 Vol. 49 No. 3 THE HUNGRY BIRD

Ticks

Dave Leatherman A big bird is riding the back of a big animal, the beak of the ridee near the ear of its ride. One of the cutesy animal sites on the Internet would probably interpret this as “bird tells Bambi a secret,” or “birdy hitches a ride.” What’s really going on is likely an example of a “cleaning mutual- ism,” which is the subject of this piece. “Symbiosis” was first described in 1879 as, “a relationship between two unlike organisms” by Heinrich Anton de Bary, a definition widely accepted today (Douglas 1994). That sounds sort of like most human relationships. As with them, there are different categories of symbiosis. Some benefit both partners, called a “mutualism.” Some are character- ized by one member benefitting with the other being unaffected, which is called a “commensalism.” A third major type involves one benefactor and one sufferer, or a “parasitism” (Paracer 2000). Thinking about your relationships? For a time, give it a rest. This is about birds. Before getting too far along, the person to whom recognition of “sym- biosis” in nature is first credited warrants recognition. He was Albert Bernhard Frank, a German botanist and mycologist who postulated in the late 1800s, amid considerable controversy, the existence of two sym- bioses: particular fungi and host plant roots combining to form “mycor- rhizae”, and certain algae and fungi comprising “lichens”. In retrospect, these amount to an amazing contribution to our understanding of the natural world (Frank, 2005). The literature contains many examples of mutualistic symbioses be- tween birds and mammals. Perhaps the best known worldwide exam- ples of so-called “cleaning mutualisms,” where the food objects of the bird are mostly ectoparasitic ticks and blood-feeding flies of the host mammal, involve oxpeckers (Buphagus spp.) in the African savannahs riding the backs of giraffes, rhinos, hippos and gazelles (Atwell 1966, Mooring 1996). Oxpecker species are thought to be the only “obligate” (as opposed to “opportunistic”) tick-feeding birds in the world, with many of them containing an average of 400 ticks in their stomachs when examined. Examples of opportunistic tick-feeding by birds from open habitats include the Fan-tailed Raven (Corvus rhipidurus) and camels (Camelus dromedarius) (Lewis 1989), Pale-winged Starlings (Onychognathus na- bouroup) and mountain zebras (Equus zebra) (Penzorn 1989), Black-billed Magpies (Pica pica) and moose (Alces alces) (Samuel 1991), Yellow-billed Bulbuls (Alophoixus phaeocephalus) and klipspringers (Oreotragus oreotra- gus) (Roberts 1993), Yellow-headed Caracaras (Milvago chimachima) and

Colorado Birds Summer 2015 Vol. 49 No. 3 139 both cattle (Bos taurus) and capybaras (Hydrochaeris hydrochaeris) (Sick 1984), and Cattle Egrets (Bubulcus ibis) associated with a wide variety of ungulates (Burger 1982). Apparently the incidence of birds feeding on ticks from mammals in closed-canopy (i.e., “forested”) habitats is less well known. One extreme- ly interesting set of observations involved tick-cleansing by the Black Caracara (Diapterus ater) from the Brazilian tapir (Tapirus terrestris), and a predominately fruit-eater, the White-winged Trumpeter (Psophia leuco- ptera), from gray brocket deer (Mazama gouazoubira) (Peres 1996). The caracara-tapir association actually involves “contact calling” by both members of the pair, apparently necessitated by the short sight distances of dense forests and which facilitates their getting together. Such calling by both parties probably indicates a highly-evolved, long- existing relationship. Indigenous tribes that hunt tapir recognize these calls, which they use to improve their success (Peres 1996). Let’s get something out of the way here regarding the Cattle Egret. Apparently the “truism” that they consume a lot of ticks from cattle and other hoofed animal associates is a myth. One Arabic name for them, “Abu Qerdan,” meaning “father of ticks,” accrues from the abundance of ticks in Egyptian heronries (Telfair 2006). A common name for Cattle Egret outside the US is “Tick Bird,” but food studies seem to show this name also has more to do with assumption than consumption (Telfair 2006). In well-studied diets over several localities worldwide, ticks make up a rather low incidence of 0.1-3.7% of all items analyzed (Petney 1993). Apparently the bill of Cattle Egrets is not built for tick removal, akin to obtaining and eating individual peas from a pod with a shovel (Telfair 2006). So which North American birds DO eat ticks attached to mammalian hosts? Besides the superstar of this subject, Black-billed Magpies, other species reported to eat ticks obtained from hoofed hosts are Gray Jays (Perisoreus canadensis) (Addison 1988), Common Raven (Corvus corax) (Addison 1988) and perhaps Western Scrub-Jay (Aphelocoma californica) (Isenhart 1985). Are these non-magpie corvids doing these things in Colorado? The answer is “probably.” Apparently, the winner of “The Big Year” among Colorado birds, defined as the one accumulating the most ticks, is overwhelmingly the Black-billed Magpie. The literature indicates the most likely host to be moose and the tick species involved as the winter tick (Dermacentor al- bipictus). We have other hosts of ticks that serve as potential bird eateries, namely mule deer (Odocoileus hemionus), wapiti (Cervus elaphus) and bighorn sheep (Ovis canadensis). Perhaps additionally, other wild un- gulates such as white-tailed deer (Odocoileus virginianus) and domestic

140 Colorado Birds Summer 2015 Vol. 49 No. 3 animals such as cattle, horses (Equus ferus) and bison (Bison bison) could be included. I’m not sure about mountain goats (Oreamnos americanus), but this introduced animal spends the great majority of its time in cold alpine habitats not favorable for tick development. Likewise, it does not seem likely that pronghorn (Antilocapra americana) would be exposed to cleaning by birds, except maybe those individuals harboring spinose ear ticks by bird species yet to be confirmed as feeding on them (see below) (Fitzgerald 1994). In addition to the tick species listed above (all family Ixodidae), other ixodids found in Colorado infesting the above-listed hooved animals and possible candidates for consumption by birds, are the Rocky Mountain wood tick (Dermacentor andersoni) and the American dog tick (D. varia- bilis). These are the two species also most likely to feed on birders and other humans. A fourth tick, the lone star tick (Amblyomma americanum) possibly occurs in extreme southeastern Colorado, where white-tailed deer, mule deer and bighorn sheep, along with a few magpies, dwell. The spinose ear tick (Otobius megnini) occurs in the ears of large animals and may explain episodes suggestive of mutualistic cleaning between birds, including Brown-headed Cowbird (Molothrus ater) and ungulates. The brown dog tick (Rhipicephalus sanguineus) and 20+ other species of ticks (including many soft ticks in the family Argasidae) are known from Col- orado but their hosts are usually small animals not likely to be exploited by birds. Lastly, the infamous vectors to humans of Lyme Disease, the black-legged tick (Ixodes scapularis) and the western black-legged tick (I. pacificus), both mostly found on small mammals and deer, have not been confirmed within CO (Cranshaw 2014). I have not personally observed a magpie gleaning ticks from a moose, which does not mean much. Based on the biology of all three organisms involved, the most likely season of occurrence would be March-April in areas where the moose has been introduced and become established (northwest quadrant of the State, Grand Mesa, Creede and perhaps oth- er areas). Historically, my travels have rarely put me in the right part of the state during the right months. My assumption has always been an incidence of a magpie cleaning the body of a big animal was a clear-cut mutualism. The bird gets a nutri- tious meal while ridding the tick host of blood-sucking parasites, right? But in researching this article, the Birds of North America account for magpie contains a very interesting paper that perhaps thickens the plot (Samuel 1991). Observations in this article involve not only the extraction and on-the-spot consumption of winter ticks, but the caching of ticks care- fully removed alive from moose. The ticks are primarily cached on bare ground, as opposed to areas of snow. It is commonplace for moose to

Colorado Birds Summer 2015 Vol. 49 No. 3 141 be infested with large numbers of ticks, sometimes as many as 70,000! (Samuel 1990). Such a parasite load almost always elicits responses from the moose, prominent among them being acts of self-grooming. Many ticks die in the process of the big animal forcefully rubbing against hard objects like a tree trunk, rock or ground. Many ticks not killed outright are knocked off onto microsites where they do not survive. The authors theorize the act of caching, including the choice of bare-ground sites for deposit, might contribute to greater survival of female ticks to egg-laying age and, thus, a larger tick population. Climate change also appears to be a contributor to higher tick populations. All this is bad news for moose. Clearly, heavy tick populations stress moose, which of themselves can cause disease, plus a tremendous loss of blood and energy. Attempts to rub the annoyances off cause more energy loss, as well as considerable hair removal. Such abnormally “bald”, gray-from-a-distance individuals are called “ghost moose.” Excessive hair loss can lead to moose mortality during cold weather. Guess which bird is the primary scavenger of dead moose? Yep, magpies. It seems magpies could benefit in two ways from an increased tick population. They could consume abundant ticks directly, and/or partake of resultant moose carrion, both at a time of high energy demand for magpies just prior to their breeding season (Samuel 1991). Are magpie-moose interactions examples of mutualism, parasitism, or a little of both? Opportunism or orchestration? As always, teasing answers from our interconnected, immensely complicated world are not easy. My personal experience with the association of magpies and tick- infested mammals, neither of them moose, consists of these: On 16 March 1989 about 9 miles west of Rustic (Larimer County) in Poudre Canyon I saw a group of 15+ bighorn sheep attended by 5 magpies. The magpies intently probed the fur of the sheep and removed marble- sized objects, which I now know to have been engorged ticks (Fig.1 ). As anyone who has been outdoors in tick country knows, where ticks decide to settle for a blood-meal can be a delicate, private matter. Often such places never receive sunshine. For personal hygiene, we have the advan- tage of a mirror and tweezers. For a large ungulate host, self-riddance, at least from certain body regions on certain individuals, would seem to be impossible. Likewise, allowing another organism, especially a rather raucous one with a long, sharp beak, access to intimate places for the removal process requires trust that only comes from positive experience. At least that is how I interpreted the very different demeanor of young sheep with a magpie on their body vs. older adult sheep. The former were skittish and jumpy, not so sure what was happening. Did I see one of them charade the equivalent of: “Halt, who goes there!!??,” or “Holy schnikes!!!!”? Picture a little kid at the doctor’s getting his first shot. In stark contrast, veteran sheep calmly allowed free access, sometimes

142 Colorado Birds Summer 2015 Vol. 49 No. 3 by two magpies simultane- ously operating at opposite ends of the “customer”. Picture an elderly woman at the parlor having hair curled and dyed by her beautician and personal confidant of many years. The second episode was 21 January 2014 just west of the south end of Horse- tooth Reservoir (Larimer County) on the property of Dave Steingraeber and Fig. 1. Bighorn Sheep and Black-billed Magpies, Up- Carol Simmons. This time per Poudre Canyon, Larimer County, 16 March the tick supply was a small 1989. Photo by David Leatherman herd of mule deer resting in the shade of overtop- ping ponderosa pines. I suppose Fig.2 could be interpreted as “telling a secret” to the deer. In real- ity, mammalian ears are a common end-destination for hungry ticks looking for protected, easy access to blood-engorged tissue. The big ears of mule deer are probably a common site for magpie grooming for this reason and because they are difficult for the deer to self-groom. David Dowell’s wonder- Fig. 2. A Mule Deer and Black-billed Magpie, west of ful photo (Fig.3) of a young Horsetooth Reservoir, Larimer County, 21 January mule deer attended by a 2014. Photo by David Leatherman duo of magpies was taken in southwest Boulder County this spring. The literature readily available implies corvids are the primary spe- cies, besides birders, involved in “ticking”, if you will. But what about other birds? The Giant Cowbird (Scaphidura oryzivora) has been ob- served in western Amazonia eating what are thought to be ticks from both cattle and capybaras (Robertson 1988, Peres 1996). What is that fe-

Colorado Birds Summer 2015 Vol. 49 No. 3 143 male Brown-headed Cow- bird doing in Tom and Mary France’s photo in Fig.4? The well-known as- sociation of cowbirds and livestock is similar to that of Cattle Egrets, where the cloven creature’s feet stir insects from the grass that are then eaten by the birds. My friends reported the cowbird was not at the feet of the cow but rather tipping down in its ear more than once for Fig. 3. Young Mule Deer and Black-billed Magpies, unidentified morsels. Was Boulder Mountain Parks, Boulder County, 16 April this an incident of rather 2015. Photo by David Dowell small cowbirds (com- pared to magpies) getting spinose ear ticks or some other type of tick down in the ear canal? Whatever happened, it appears to be an example of mutualistic cleaning of an arthropod and is most interesting. I would welcome ob- servations from readers involving magpies or any bird species (other cor- vids?) and mammalian Fig. 4. A female Brown-headed Cowbird and cow, near tick hosts. We need to Bobcat Ridge Natural Area entrance, Lamar County, document the Colorado 2 June 2012. Photo by Tom and Mary France associations of magpies and ticks with wapiti, moose and white-tailed deer. I’m not sure if a magpie would be so bold as to land on a black bear. Do they ever groom domestic animals, such as cattle, horses, llamas or even large dogs? Lots of gaps in our knowledge for us to “tick.”

ACKNOWLEDGMENTS I thank Tom and Mary France for scanning and helping improve the old print images of bighorn sheep being attended by magpies, and for use of their photo of a cowbird

144 Colorado Birds Summer 2015 Vol. 49 No. 3 bending a cow’s ear. David Dowell was nice enough to allow use of his magpie/mule deer photo. And I appreciate David Steingraeber and Carol Simmons allowing free access to their property.

LITERATURE CITED Addison, E. M. and R. F. McLaughlin. 1988. Growth and development of winter tick, Dermacentor albipictus, on moose, Alces alces. J. Parasitol. 74:670-678. Addison, E. M., R. D. Strickland, and D. J. H. Fraser. 1989. Gray jays, Perisoreus ca- nadensis, and common ravens, Corvus corax, as predators of winter ticks, Dermacentor albipictus. Can. Field-Nat. 103:406-408. Bezuidenhout, J. D. and C. J. Stutterheim. 1980. A critical evaluation of the role played by the red-billed oxpecker Buphagus erythrorhynchus in the biological control of ticks. Onderstepoort J. Vet. Res. 47:51-75. Cranshaw, W. and F. Peairs. 2014. Colorado ticks and tick-born diseases. Cooperative Extension Fact Sheet 5.593, CO State Univ. Fort Collins. Douglas, Angela. 1994. Symbiotic interactions. Oxford Univ. Press, Oxford. Fitzgerald, James P., Carron A. Meaney, and David M. Armstrong. 1994. Mammals of Colorado. Denver Mus. of Nat. History and Univ. Press of Colorado, Niwot, CO. Frank, B. 2005. On the nutritional dependence of certain trees on root symbiosis with belowground fungi (An English translation of A. B. Frank’s classic paper of 1865). Mycorrhiza 15(4):267-275. Isenhart, F. R. and D. F. DeSante. 1985. Observations of scrub jays cleaning ectoparasites from black-tailed deer. Condor 87:145-147. Lewis, A. D. 1989. Notes on two ravens Corvus spp. in Kenya. Scopus 13:129-131. Mooring, M. S. and P. J. Mundy. 1996. Interactions between impala and oxpeckers at Matobo National Park, Zimbabwe. Afr. J. Ecol. 34:54-65. Paracer, Surindar and Vernon Ahmadjian. 2000. Symbiosis: an introduction to biological associations, Oxford [Oxfordshire]: Oxford University Press. Peres, Carlos A. 1996. Ungulate ectoparasite removal by Black Caracaras and Pale- winged Trumpeters in Amazonian forests. Wilson Bull. 108(1):170-175. Petney, T. N. and O. B. Kok. 1993. Birds as predators of ticks (Ixodoidea) in South Africa. Exp. Appl. Acarol. 17:393-403. F’enzhorn, B. L. and I. G. Horak. 1989. Starlings, mountain zebras and ticks. Koedoe 32:133-134. Samuel, W. M. and D. A. Welsh. 1991. Winter ticks on moose and other ungulates: fac- tors influencing their populations size. Alces 27:169-182. Samuel, W.M., M.S. Mooring and I.O. Aalangdong. 2000. Adaptations of winter ticks (Dermacentor albipictus) to invade moose and moose to evade ticks. Alces 36:183-195. Sick, H. 1984. Ornitologia brasileira: uma introducao. Vol. 1. Editora Univ. de Brasilia, Brasilia, Brazil. Telfair II, Raymond C. 2006. Cattle Egret (Bubulcus ibis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/113. Trost, C. H. 1999. Black-billed magpie (Pica pica). In A. Poole and F. Gill (eds.) The birds of North America, No. 389. The Birds of North America, Inc., Philadelphia, PA.

Dave Leatherman, [email protected]

Colorado Birds Summer 2015 Vol. 49 No. 3 145 At the end of each “The Hungry Bird” article, I usually ask readers to contribute additional observations related to the immediate subject. Graciously, some of you have done this. Who could forget Jeannie Mitchell’s photograph of a Barred Owl with a crayfish taken in eastern Kansas? Last winter’s “The Hungry Bird” (Volume 49, No. 1) dealt with snakes, and I tried to list all the Colorado birds for which I could find mention of serpentine diets. Great Horned Owl was not one of them, although this is probably a species we all might expect as being in on the fun. Well, Bob To- mas took this excellent photo in Broomfield County, just west of Stearn’s Lake near South 104th Street on 6 May 2015. He was riding his bike, minding his own business, when this big predator and its meal demanded attention. This is definitely a large garter snake, probably a Plains Garter Snake (Thamnophis radix). We thank Bob for paying attention, knowing how to use his camera and sharing this exciting episode. - Dave Leatherman

Great Horned Owl with a probable Plains Garter Snake, Stearn’s Lake, Broomfield County, 6 May 2015. Photo by Bob Tomas

146 Colorado Birds Summer 2015 Vol. 49 No. 3 Common Ravens Benefit from Human Subsidies in Gunnison’s Sagebrush Sea Patrick Magee Abstract Common Raven (Corvus corax) numbers have increased dramati- cally in the Gunnison Basin and throughout western North America in the last 50 years. The rise of ravens corresponds to the dramatic altera- tion of western landscapes including the sagebrush biome. Human sub- sidies and pronounced fragmentation of the landscape benefits ravens. Recently, ravens were implicated as primary nest predators of Greater Sage-Grouse (Centrocercus urophasianus) in the Great Basin, but little is known regarding the effects of raven depredation on Gunnison Sage- Grouse (Centrocercus minimus) nests and chicks. I studied ravens in Colorado’s Gunnison Basin in relation to human resources. Twelve sites with varying human footprints were surveyed from August 2013 to July 2014. I conducted point counts at each site three times per sampling day and twice each month. Ravens, ubiquitous in the study area, were pres- ent at all sites, at all times of day and in all seasons. I detected over 81 percent of all ravens at the landfill and the birds concentrated there in the morning and evening throughout much of the year. The pattern changed to continuous use throughout the day in winter, particularly on days with inclement weather. Ravens were highly active in morning and mid-day periods, from fall through early spring especially, flying and presumably foraging over much of the study area. In winter, roadkill highway car- casses were an important part of their diet. Ravens used town sites such as grocery store parking lots and the residential areas less than other sites. I watched ravens flying low and circling over sagebrush during the Gun- nison Sage-Grouse nesting season, but never saw any direct interactions with sage-grouse. To proactively address potential impacts of ravens on the Gunnison Sage-Grouse, I recommend the development of an inte- grated raven management strategy that potentially includes lethal removal, aversive conditioning and reduction of human subsidies. Future research should determine the efficacy of management actions to reduce human subsidies on subsequent raven abundance.

Introduction Back in the 1950s, Common Ravens (Corvus corax) were rela- tively scarce, however, since 1968 their numbers have skyrocketed by 500–7,600 percent across the western U.S. (Sauer et al. 2014). In

Colorado Birds Summer 2015 Vol. 49 No. 3 147 the Gunnison Basin in 1954, birders saw one common raven during the county’s first Christmas Bird Count; in 2014, the count was 540. Today, many people are concerned with the challenge of having too many ravens rather than too few. As ecological generalists, ravens have adapted rapidly to the changing landscapes of the West that brought a dramatic rise in hu- man subsidies. For example, ravens devour a variety of novel food sources including roadkill carrion, landfill bonanzas, agricultural fruits and grains, rodents in freshly hayed meadows, offal left by big game hunters and the afterbirth of livestock. In addition and quite remark- ably, they also are known to attack sickly lambs and calves — pok- ing out and consuming their eyeballs (Boarman and Heinrich 1999). Bridges, oil derricks, railroad trusses, billboards and an extensive net- work of transmission lines and towers serve as nesting, roosting and perching sites (Boarman and Heinrich 1999). Common Ravens in- novate, adapt, solve problems and thrive in fragmented, altered land- scapes where humans have left their footprints. In the places where this human-subsidized predator thrives, increasingly it conflicts with humans and wildlife populations from desert tortoises to Sandhill Cranes (Boarman 2003, Austin and Mitchell 2010). Increasingly, ra- vens inhabit the sagebrush steppe and pose an uncertain threat to the imperiled and iconic sage-grouse species. The once vast sea of sagebrush encompassed 760 million acres of western North America, but conversion and carving left only 410 million acres, much in a degraded and fragmented state (Schroeder et al. 2004). “Human progress” in the form of agriculture, urbaniza- tion, transmission lines and roads, among other modifications, have all contributed to the loss of sagebrush habitat (Leu et al. 2008). With these changes wildlife populations have declined (Knick et al. 2003, Boyle and Reeder 2005, Welch 2005) including Greater Sage- Grouse (Centrocercus urophasianus) that occupies 56 percent of its historic range, and Gunnison Sage-Grouse (Centrocurcus minimus) that occurs in just 10 percent of its historic range (Schroeder et al. 2004). Using video cameras hidden near nest sites, researchers have linked ravens directly to depredation of Greater Sage-Grouse eggs and chicks (Coates et al. 2008, Coates and Delehanty 2008, Coates and Delehanty 2010, Lockyer et al. 2013). At the Idaho National Laboratory, over the last few decades the predatory bird community has been reshuffled with raven densities four to nine times higher than three species of buteo hawks and of the four avian predatory species, almost 50 percent of nests belong to ravens (Coates et al. 2014). That 73 percent of their nests are located on anthropogenic structures compared to two to three percent for the buteos, suggests

148 Colorado Birds Summer 2015 Vol. 49 No. 3 a mechanism for raven dominance (Coates et al. 2014). While the degradation of the sagebrush ecosystem has led to long-term popu- lation declines in sagebrush obligate species, including sage-grouse (Connelley et al. 2004, Schroeder et al. 2004, Knick and Connel- ley 2011), habitat fragmentation, human infrastructure and expan- sion of non-native vegetation have all benefitted ravens (Coates et al. 2014, Howe et al. 2014) (Table 1). While researchers have definitively linked Greater Sage-Grouse nest destruction to ravens (Coates et al. 2008, Coates and Delehanty 2008, Coates and Dele- hanty 2010, Lockyer et al. 2013, Howe et al. 2014, Coates et al. 2014) less is known about impacts of ravens on Gunnison Sage- Grouse. The purpose of this study was to determine how ravens used sev- eral sites in the Gunnison Basin, where 85 percent of the global population of the Gunnison Sage-Grouse resides (Gunnison Sage- Grouse Rangewide Steering Committee 2005). I wanted to know if ravens used a certain site at specific times of day or seasons. I visited sites with relatively low human impact (sagebrush) and other sites with an increasingly greater human footprint. While the study did not directly assess how ravens impacted Gunnison Sage-Grouse, it

Table 1. Response of Common Ravens to human features of sagebrush landscapes.

Human Feature Raven Response Literature Reference Electrical transmission lines Perch sites Coates et al. 2014, Lammers and Collopy 2007, Prather and Messmer 2010, Slater and Smith 2010, Howe et al. 2014 Electrical transmission lines Nest sites Coates et al. 2014, Howe et al. 2014 Roads and highways Road kill food source Coates et al. 2014 Edge habitat preferred Invasive plant community Edge habitat preferred Howe et al. 2014, Coates et al. 2014 Conversion to agricultural Consume waste grain Evans 2004, Manzer and Hannon 2005, Edge habitat preferred Coates et al. 2014 Habitat fragmentation Edge habitat preferred Dinkins 2013, Coates et al. 2014, Howe et al. 2014 Increased frequency of wildlife and Edge habitat preferred Howe et al. 2014 conversion to annual grass Suppression of wildfre and piñon- Nest sites Howe et al. 2014 juniper aforestation Edge habitat preferred Decreased sagebrush canopy cover Increased grouse predation Manzer and Hannon 2005, Coates and Delehanty 2010, Coates et al. 2014 Landfll Food bonanza Heinrich 1989, Boarman and Heinrich 1999 Urbanization Food, nest sites, roosts Leu et al. 2008

Colorado Birds Summer 2015 Vol. 49 No. 3 149 was a first step in better understanding local raven ecology and pro- viding insight into raven use of sagebrush and associated habitats. I predicted that ravens would use human-modified sites rich in re- source subsidies more than less altered sagebrush habitat.

Methods To accomplish my goal, I observed ravens from August 2013 to July 2014 in the Gunnison Basin located in south-central Colorado (Bird Conservation Region 16). At 7,703 feet above sea level, Gun- nison (population 5,854) occupies a high-elevation, intermountain basin, and during the study period the annual precipitation was 60 percent of the long-term average (6.3 inches; dry year) (Western Regional Climate Center 1900-2005, www.wrcc.dri.edu). Overall the average temperature during the study period was 37.3oF, slightly above the long-term average temperature for Gunnison (36.9oF) (USClimatedata.com). Below 8,000 feet, sagebrush dominates the Gunnison Basin with Tomichi Creek and the Gunnison River me- andering through hay meadows, skirting the edge of Gunnison. Wil- low thickets (Salix spp.) and narrowleaf cottonwood (Populus an- gustifolia) gallery forests along stream corridors represent important densely vegetated riparian habitats that contrast with more open upland landscapes. I visited 12 sites including three sagebrush-dominated sites. De- spite being relatively undisturbed, the sagebrush sites had plenty of human activities including dirt roads, transmission lines, disturbed vegetation and mining exploration dig sites. The remaining nine sites included an irrigated hay meadow at the Lost Miner horse ranch, the Gunnison wastewater treatment plant, the Gunnison County landfill, a one-mile section of U.S. Highway 50, the Gun- nison County airport, the Dos Rios Golf Course, the Western State Colorado University campus, a one-mile loop along the streets in a residential area of Gunnison and the parking lot of the local City Market grocery store. Each time I visited a site (three times a day, twice per month for the entire year), I identified Common Ravens and American Crows (Corvus branchyrhynchos) by sight and sound and using a six-minute point count I tallied the number of individuals of each species. By year’s end I had conducted 857 point counts.

Results

Common Raven and American Crow use of sample sites I observed ravens at all 12 sites and on 48 percent of the counts

150 Colorado Birds Summer 2015 Vol. 49 No. 3 (412 out of 857), whereas crows were present on 20 percent (175 out of 857) of the counts (Fig. 1). Overall, I counted 10,384 ravens and 556 crows over the entire study. The vast majority of ravens were recorded at the landfill (81.6 percent) followed by the Cabin Creek sagebrush site (5.6 percent) and the ranch (4.2 percent). Crow prev- alence was highest in the residential area (36.7 percent) followed by the grocery store parking lot (20.2 percent) and the golf course (19.6 percent). Ravens were present 94 percent of the time at the landfill and 81 percent of the time at the ranch site. They occurred 60 percent of the time at the Long Gulch sagebrush site and 58 percent of the time at the wastewater treatment plant (Fig. 1). In contrast, they were present only 15 percent of the time at the grocery store parking lot, 22 percent of the time at the airport and 25 percent of the time in the city residential area. Ravens were present on average 50 percent (38-60 percent range) of the time at sagebrush sites.

Common Raven and American Crow use of sites relative to time of day Ravens used the 12 sites differently relative to the three time pe- riods (morning, mid-day and evening). A distinct bimodal pattern of use appeared at the landfill and two of the sagebrush sites adja- cent to the landfill in which ravens had relatively high abundance in the morning and evening and had lower abundance at mid-day. At five sites ravens had relatively high abundance during mid-day with lower abundance in the morning and evening (ranch, highway, university, residential and wastewater facility). At five sites ravens showed a pattern of lowest use in the evening (golf course, grocery store, university, highway and ranch). Similarly, crows used sites differently at different times of day. Crows did not visit the three sagebrush sites at all and rarely used the highway and airport. Interestingly, crows strongly used the most urban sites (residential, grocery store, golf course and uni- versity) especially during morning and mid-day, but less so in the evening.

Common Raven and American Crow use of sites relative to season and time of day Ravens used sites in unique ways at different seasons and times of day. In fall, more ravens occurred at sites in the morning and evening. In winter, they followed a different pattern where raven abundance was higher in morning and mid-day, and lower in the evening. By spring and into summer, a strong bimodal activity pat-

Colorado Birds Summer 2015 Vol. 49 No. 3 151 A

B

Fig. 1. Percent of total Common Ravens (A) and American Crows (B) counted throughout the study by site. The sites are more or less arranged from rural (least anthropogenic influence) on the left (sagebrush reference sites) to urban (highest an- thropogenic influence) on the right. The sagebrush sites from left to right are Cabin Creek, Long Gulch, and McCabe’s. Data collected from August 2013 to July 2014 in the Gunnison Basin, Colorado.

tern had returned (Table 2). In late fall and winter, I observed more ravens in the morning and at mid-day, but this pattern disappeared in spring and summer. Ravens showed a pattern of increased use

152 Colorado Birds Summer 2015 Vol. 49 No. 3 from fall into winter and spring with declining use in summer. These observations support the idea that ravens are active during winter and early spring in the morning and mid-day periods and are highly visible at many sites. Crows had a consistent pattern of highest use in morning, intermediate use at mid-day and lowest use in evening in all seasons (Table 2).

Roadkill and carcass use I observed the first roadkill along U.S. Highway 50 in late No- vember 2013, and carcasses accumulated over the course of the win- ter, peaking by mid-March 2014. Incidence of roadkill surged during winter storms with mule deer taking the hardest hit (29 fresh car- casses counted). Other roadkill species included raccoons, red fox, elk, striped skunk, Gunnison’s prairie dog, Wyoming ground squir- rel, coyote, mink and an unidentified bird carcass. Ravens prized fresh mule deer carcasses as an important source of winter and spring

Table 2. Average number and average frequency of occurrence of ravens in relation- ship to season and time of day. Data were collected from August 2013 to July 2014 in the Gunnison Basin, Colorado.

Common Raven Season Variable Morning Day Evening Pattern Fall Abundance 11.8 5.9 6.2 Weak bimodal Frequency 0.40 0.44 0.29 Evening low Winter Abundance 16.2 16.6 6.6 Evening low Frequency 0.69 0.62 0.47 Evening low Spring Abundance 15.9 5.3 22.2 Bimodal Frequency 0.61 0.58 0.51 Steady Summer Abundance 14.1 4.8 18.6 Bimodal Frequency 0.38 0.27 0.41 Weak bimodal American Crow Fall Abundance 1.15 0.67 0.31 Evening low Frequency 0.29 0.22 0.08 Evening low Winter Abundance 1.15 1.26 0.08 Evening low Frequency 0.29 0.29 0.07 Evening low Spring Abundance 0.72 0.65 0.44 Evening low Frequency 0.25 0.19 0.19 Morning high Summer Abundance 0.60 0.35 0.33 Morning high Frequency 0.19 0.14 0.19 Weak bimodal

Colorado Birds Summer 2015 Vol. 49 No. 3 153 food (Fig. 2). For example, on 16 January 2014, of six fresh carcasses observed after a snowstorm, ravens attended four, including 33 on a single deer corpse! Further, ravens heavily scavenged several human- killed coyote carcasses dumped along BLM roads in early winter.

Discussion What can I conclude about my observations of Common Ravens in Gunnison? This controversial species is nearly ubiquitous in the study area. Ravens were present at every site and during all 48 sam- pling dates. They were present at every time of day, and I observed them on approximately 50 percent of the 857 point counts. In con- trast, I only detected American Crows 20 percent of the time. They did not use any of the sagebrush sites and their highest use was at four intensely urban sites (grocery store, residential, golf course and uni- versity). Crows matched my hypothesis: that the birds would be as- sociated with the most urbanized sites and less likely to associate with the least urban sites in the sagebrush. Ravens, on the other hand, did not strictly follow the hypothesized pattern. Where the human footprint on the land was highest, including the grocery store parking lot and the residential area, raven use was the lowest. While ravens clearly benefit from human activities, they appear to prefer sites with a combination of human and natural features. While ravens used two of the sagebrush sites regularly, much of this use was associated with

Fig. 2. Number of carcasses (dotted black line) and number of ravens using roadkill (gray shading) counted along an 11-mile segment of U.S. Highway 50 in Gunnison, Colorado (MM 153-164) from August 2013 to July 2014. The peaks in use in Janu- ary and February correlated with snowstorms.

154 Colorado Birds Summer 2015 Vol. 49 No. 3 their movement to and from the landfill. In contrast, ravens flew low over the third sagebrush site (McCabe’s) and were observed feeding on human-generated carcasses. The landfill was by far the most used site by ravens in the study area. I counted 8,477 ravens at the landfill throughout the year, which accounted for 81.6 percent of all raven observations. The to- tal number of ravens counted represents a conservative estimate as I did not have a complete view of the landfill trash pile. The unofficial high count during the study was more than 600 ravens at one time at the landfill. Ravens showed distinct daily patterns of use that varied by site. Ravens exploited the landfill more in the morning and the evening, but largely departed the landfill during mid-day. The pattern changed in winter, especially during inclement weather, when mid-day counts were highest. This is likely due to a strategy of foraging (and playing in the snow) all day at the landfill (especially during snow storms) and returning to the roost early in the day during winter. Low ra- ven counts in the late afternoon at all twelve sites beginning in late November support this contention that raven behavior changes in winter toward early movement to the landfill and their roost site. After ravens departed the landfill in the morning, use picked up at several sites in the study area (especially the ranch and wastewater plant, but also the highway, university and residential area). Howev- er, raven abundance at the other sites did not nearly account for the number of ravens using the landfill in the morning and evening. This pattern is supported by other research where landfills provide the main food bonanza but raven use of the surrounding environment is dispersed (Boarman et al. 2006). Perhaps many ravens roosted dur- ing the day in dispersed day roost sites including mature cottonwood trees, and during summer when the trees were fully leafed out, thus concealing the ravens. During fall and into winter, day use was much more pronounced, especially along the Gunnison River corridor. Ravens apparently were foraging throughout the day, representing a dramatic shift from their summer day roost behavior. Raven use generally declined in spring perhaps as a combined re- sult of dispersal for breeding, migration and over winter mortality (Boarman et al. 2006). General activity at all sites was relatively low beginning in late March and persisting through mid-summer.

Management Implications

Common Raven management justification Video footage suggests that ravens are the primary nest predator

Colorado Birds Summer 2015 Vol. 49 No. 3 155 of Greater Sage-Grouse (Coates and Delehanty 2008, Coates et al. 2008, Lockyer et al. 2013). Likely ravens depredate eggs and pos- sibly prey on Gunnison Sage-Grouse chicks as well. In Nevada, ra- vens depredated half the Greater Sage-Grouse nests contributing to a discouraging 22.5 percent nest success (Dan Gibson, unpublished data). Research justifies developing an integrated raven manage- ment (IRM) program to reduce raven depredations on Gunnison Sage-Grouse through a strategic planning process and with a diverse menu of management options including 1) lethal removal of ravens, 2) aversive conditioning, and 3) reduction of human subsidies (Bui et al. 2010). Lethal removal is generally expensive and an ineffective long-term solution to raven depredation problems, and thus should be used only as a second-tier strategy after non-lethal reduction of human subsidies is fully implemented. The IRM strategy should in- clude monitoring efforts to provide an adaptive management process that emphasizes gaining understanding of the effectiveness of various management approaches.

Lethal removal of Common Ravens In an effort to control raven numbers in Nevada, USDA Wildlife Services removed 684 ravens in 2002 and 2003, effectively reducing raven density from 5/km2 to 0.31/km2 (Coates and Delehanty 2004). Greater Sage-Grouse nest success increased from 42 percent pre- control to 74 percent after control was initiated (Coates and Dele- hanty 2004). Despite some successes, raven control studies generally conclude that lethal removal of ravens is ineffective at providing recovery of sage-grouse (Hagan 2011). For example, where Wildlife Services reduced raven population density by 61 percent from 2008- 2011 in Wyoming, Greater Sage-Grouse nest success did not measur- ably improve (Dinkins 2013). Lethal removal of ravens requires a take permit from the U.S. Fish and Wildlife Service, as ravens are protected under the Migratory Bird Treaty Act of 1918. Typically, USDA Wildlife Services is em- ployed to conduct such lethal control projects. The agency regularly employs DRC-1339-tainted hard-boiled chicken eggs as bait to lure ravens to the lethal poison. Ingestion of the toxin leads to death by kidney failure or depression of the central nervous system in one to two days (BLM 1990). A complexity to raven lethal control relates to targeting individu- al ravens. The most significant threat to sage-grouse is from breeding adult ravens that forage intensively in established territories (Kristan et al. 2004). Reducing raven numbers at the landfill where juvenile crowds form, may not have a noticeable effect on raven activity in

156 Colorado Birds Summer 2015 Vol. 49 No. 3 the sagebrush as the targeted birds at the landfill are not the same so- cial class as the birds that potentially feed on eggs of ground-nesting sagebrush species. Ravens that gather in large groups are most likely dominated by juveniles that will often congregate at food bonanzas hoping to overwhelm dominant adult birds (Boarman and Heinrich 1999). My observations support this hypothesis as I only saw single or paired ravens foraging low over sagebrush. Targeting adult territo- rial birds would likely remove “problem” ravens that have learned to feed on grouse eggs (Kristan et al. 2004), while non-egg-eating ravens would likely move into unoccupied territories.

Aversive conditioning Aversive conditioning or behavioral modification involves train- ing ravens to not eat sage-grouse eggs, nor to perch or nest on an- thropogenic structures. Training ravens to avoid eating sage-grouse eggs involves treating chicken eggs with unpalatable chemicals (e.g. carbachol) that make the raven sick, and thus encouraging ravens to avoid eggs as a food source (Boarman and Heinrich 1999, Bui et al. 2010). This method shows some potential but has had mixed re- sults as apparently ravens learn quickly to avoid the tainted eggs. The method may be useful if management is targeting a few problem birds, but at a population scale, taste aversion seems impractical. The plethora of existing human structures that ravens use for perch and nest sites could be outfitted with anti-perch devices including spikes and wires or nets that restrict the perching surface.

Removing human subsidies Removal of human subsidies is likely the most effective way to reduce unnaturally inflated raven populations in a sustained way. Following are several opportunities for such anthropogenic subsidy reduction in the Gunnison Basin at a variety of sites studied. Landfill. To reduce potential impacts of ravens on Gunnison Sage-Grouse, changes must take place at the Gunnison County Landfill, where 82 percent of all ravens were detected during the study. Optimally, organic food trash burial and reduction of food en- tering the landfill would greatly impact resources for the morning and evening raven concentrations. A potential innovative method has been piloted at the Crow Wing County Landfill in Brainerd, MN, that involves spraying landfill trash with a chemical deterrent called methylanthranilate, rendering the food inedible. Transmission lines. Electrical transmission lines are not just routes for electricity to be transferred from source to customer. They also serve as “roadways” for ravens to move into isolated sagebrush

Colorado Birds Summer 2015 Vol. 49 No. 3 157 landscapes that historically have lacked copious nesting and perching structures (Coates et al. 2014). In southeastern Idaho, where three of every four ravens nests on human structures, raven nest density declines with distance from transmission lines (Howe et al. 2014). Transmission lines also provide perches for ravens to scan visually for prey. The magnitude of raven use of transmission lines for nesting is undocumented in the Gunnison Basin and research is needed to de- termine the impact they have had on Gunnison Sage-Grouse. If jus- tified, a potential management action involves removing raven nests and/or reducing the use of perch and nest substrates associated with transmission poles and towers by introducing anti-perch structures. Carcasses: highway roadkill, ranching and hunting. Ravens scavenged heavily for roadkill carcasses along U.S. Highway 50 from December to mid-March. Carcass removal along U.S. Highway 50, followed by burial, would directly remove a major anthropogenic re- source that ravens use extensively in winter. In addition to carcass removal, attempts to reduce automobile/wildlife collisions are war- ranted. Innovative technologies are available to warn drivers of the presence of large mammals on the highway. Detector pads or other devices recognize the presence of an animal and trigger a flashing sign “deer on highway”. A key to these installations is locating high- way crossing focal points. In the highway stretch that I observed, the majority of carcasses were produced within a two-mile segment, between mile markers 161-163. Besides roadway carcasses, hunters and others who kill coyotes, prairie dogs and the like generate many carcasses and gut piles (or offal). Ravens have developed a strategy of following gunshots to hunters and use the offal that is left after field dressing an animal (White 2005a, White 2005b). Encouraging hunters to bury offal piles and discouraging ranchers from shooting “vermin” would reduce this human subsidy for ravens, although it may be challenging to imple- ment. Agriculture. At the ranch, ravens perched and foraged on the ground and perched in cottonwood trees or on fences in the hay fields throughout the year. They were present in the fields on the day of hay cutting in July 2013 (possibly foraging on mice) and heav- ily used fields in the spring. They also stood on top of the snow in the fields during winter – perhaps caching meat or fat from roadkills. Where cattle were present and winter-feeding operations occurred, ravens and crows regularly foraged on the ground in these pastures, but not directly within the herd. On one occasion I counted 92 crows in one field. As with other human inhabitations, ranches represent disturbed natural landscapes that attract ravens. Ranchers have the

158 Colorado Birds Summer 2015 Vol. 49 No. 3 opportunity to reduce raven subsidies associated with afterbirth dur- ing calving, carcasses of deceased livestock and waste grain. Raven hazing methods could be used following haying or in winter when ravens gather in fields where snow has been plowed for cattle feeding. Golf course. The golf course provided a unique combination of anthropogenic resources and natural features, although most of the landscape is artificially created (lawns, parking lots, dumpsters and clubhouse). Both ravens and crows used the golf course in fairly equal proportion. Crows clearly preferred lawn foraging, although they of- ten perched in cottonwoods and were observed raiding the always- open dumpster. Ravens usually flew over the golf course or used cot- tonwoods as perch sites. Golf course personnel, as well as other local restaurant owners, could easily reduce human food subsidies by man- aging their dumpsters more effectively. Gunnison residential area and grocery store parking lot. Crows were present at the sites most dramatically altered by humans through- out the year at all time periods, whereas ravens did not use these sites nearly as much. Both species perched in spruce and cottonwood trees, as well as on rooftops, fences, light poles and power/communi- cation wires. Crows ground-foraged heavily on lawns, in gardens and at bird feeders, and drank from irrigation ditches and gutters. Crows were highly associated with parking lots, scanning from light pole perches and foraging on trash in the parking lot. Dumpster manage- ment and anti-perch structures in commercial locations could reduce crow use in these locations. Airport. The airport was one of the least used sites by ravens and crows. The main observations of ravens or crows at the airport were associated with perching behavior in nearby cottonwoods and on light poles. I did not observe corvids on the runway or associated with other airport infrastructure. Sagebrush. During the nesting season I documented 17 ravens flying low and circling over sagebrush, possibly foraging. To avoid nest predation, sage-grouse hens evolved a four-point adaptive strat- egy including near constant vigilance on the eggs for 96 percent of the total incubation period, two short daily recesses for foraging dur- ing morning and evening, departure and return to nests in low light conditions, and nest placement in dense vegetation (Coates and Delehanty 2008). Ravens have adapted to these defense strategies by visually searching for sage-grouse hens during incubation recesses, in fact, most depredations occur between 6:30-9:30 A.M. or 6-7 P.M. following recesses, with the hen on the nest when discovered (Coates and Delehanty 2008). If ravens are locating Gunnison Sage-Grouse hens and following

Colorado Birds Summer 2015 Vol. 49 No. 3 159 them to nests, then habitat enhancement is the optimal tool to re- duce predation. High quality nesting habitat allows hens to remain on their nests longer and reduces recess periods (thermal habitat, water from dew and frost, some food on nest) making hens less de- tectable where horizontal cover adequately conceals nest sites. An important question remains: how does one restore sagebrush habitat? Much work is needed before humans can adequately patch up the damage they have caused in this ecosystem.

Future Research It is likely that ravens depredate Gunnison Sage-Grouse nests, as has been documented for Greater Sage-Grouse (Coates and Dele- hanty 2008, Coates et al. 2008, Coates and Delehanty 2010, Lock- yer et al. 2013), but the magnitude of raven nest destruction is not known for Gunnison Sage-Grouse. While ravens have been impli- cated as the primary nest predator for Greater Sage-Grouse in some areas, the magnitude of these depredations do not necessarily limit sage-grouse populations (Hagan 2011). A greater understanding of raven impacts on Gunnison Sage-Grouse nest success and chick sur- vival would help inform biologists of the factors limiting sage-grouse population growth. A low-cost and indirect approach to determine whether ravens consume sage-grouse or sage-grouse eggs would in- volve locating a raven nocturnal roost and examining regurgitated pellets to determine food items ingested. While I focused on where and when ravens were present, a more detailed habitat selection study would allow a more fine-tuned ex- planation of raven habitat use in relation to Gunnison Sage-Grouse. I provide indirect evidence of sagebrush use by ravens, but all three sagebrush sites were relatively close to an urban center (Gunnison) and raven use of two of the sites was influenced by use of the landfill. Raven use of more remote sagebrush sites has not been studied in the Gunnison Basin. Whether or not we know the exact impact of ravens on Gun- nison Sage-Grouse, reduction of human subsidies for ravens should be thoughtfully implemented in the Gunnison Basin. Studies should be designed in concert with management activities to measure raven response to mitigation of human resources that have supported the expansion of ravens locally in the basin.

ACKNOWLEDGEMENTS The study was conducted during 2013-14 when I was on sabbatical from Western State Colorado University; University support is gratefully acknowledged. The Gunnison Sage-Grouse Conservation Trust Fund and Colorado Parks and Wildlife (CPW) funded the study. Nathan Seward and Scott Wait both from CPW supported the study finan-

160 Colorado Birds Summer 2015 Vol. 49 No. 3 cially and conceptually. Further, Gunnison County’s Gunnison Sage-Grouse Strategic Committee and its Predation Sub-committee supported the project concept and facili- tated opportunities for funding. Jim Cochran facilitated county funding opportunities and encouraged the project. Marlene Crosby and Allen Moores of Gunnison County facilitated access to the landfill and project funding. Anne Hausler provided access to the Lost Miner Ranch. Justus Williams and Rory Magee assisted with raven counts.

LITERATURE CITED Austin, J. E., and C. D. Mitchell. 2010. Characteristics of common raven (Corvus corax) predation on sandhill crane (Grus canadensis) eggs. Northwestern Naturalist 91:23-29. BLM. 1990. Raven Management Plan for the California Desert Conservation Area: Draft. Riverside, CA. http://archive.org/stream/ravenmanagementp00unit/ravenman- agementp00unit_djvu.txt Boarman, W. I. 2003. Managing a subsidized predator population: reducing common ra- ven predation on desert tortoises. Environmental Management 32:205–217. Boarman, W. I., and B. Heinrich. 1999. Common Raven (Corvus corax), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/476 Boarman, W. I., M. A. Patten, R. J. Camp, and S. J. Collis. 2006. Ecology of a population of subsidized predators: Common ravens in the central Mojave Desert, California. Journal of Arid Environments 67:248–261 Boyle, S. A. and D. R. Reeder. 2005. Colorado sagebrush: a conservation assessment and strategy. Grand Junction: Colorado Division of Wildlife. Bui, T. D., J.M. Marzluff, and B. Bedrosian. 2010. Common Raven activity in relation to land use in western Wyoming: Implications for Greater Sage-Grouse reproductive success. Condor 112:65-78. Coates, P. S., and D. J. Delehanty. 2004. The effects of raven removal on sage grouse nest success. Proceedings of the 21st Vertebrate Pest Conference (R. M. Timm and W. P. Gorenzel, Eds.). University of California, Davis. Pages 17-20. Coates, P. S., and D. J. Delehanty. 2008. Effects of environmental factors on incubation patterns of Greater Sage-Grouse. Condor 110:627-638. Coates, P. S., and D. J. Delehanty. 2010. Nest predation of Greater Sage-Grouse in relation to microhabitat factors and predators. Journal of Wildlife Management 74:240-248. Coates, P. S., J. W. Connelly, and D. J. Delehanty. 2008. Predators of Greater Sage-Grouse nests identified by video monitoring. Journal of Field Ornithology 79:421–428. Coates, P. S., K. B. Howe, M. L. Casazza, and D. J. Delehanty. 2014. Landscape alterations influence differential habitat use of nesting buteos and ravens within sagebrush eco- system: Implications for transmission line development. Condor 116:341-356. 2014. Connelley, J. W., S. T. Knick, M. A. Schroeder, and S. J. Stiver. 2004. Conservation as- sessment of Greater Sage-Grouse and sagebrush habitats. Western Association of Fish and Wildlife Agencies. Unpublished Report. Cheyenne, WY. Dinkins, J. B. 2013. Common Raven density and Greater Sage-Grouse nesting success in southern Wyoming: potential conservation and management implications. PhD Dis- sertation, Utah State University, Logan, UT. 290 pp. Evans, K. L. 2004. A review of the potential for interactions between predation and habi- tat change to cause population declines of farmland birds. Ibis 146:1–13. Gunnison Sage-Grouse Rangewide Steering Committee. 2005. Gunnison Sage-Grouse rangewide conservation plan. Colorado Division of Wildlife, Denver, Colorado, USA.

Colorado Birds Summer 2015 Vol. 49 No. 3 161 Hagen, C. A. 2011. Predation on Greater Sage-Grouse: facts, process, and effects. Pages 95–100 in S. T. Knick and J. W. Connelly, editors. Greater Sage-Grouse: ecology and conservation of a landscape species and its habitats. Studies in Avian Biology, Univer- sity of California Press, Berkeley, USA. Heinrich, B. 1989. Ravens in winter. Summit Books, New York. 379 pp. Howe, K. B., P. S. Coates, and D. J. Delehanty. 2014. Selection of anthropogenic features and vegetation communities by nesting Common Ravens in the sagebrush ecosystem. The Condor: Ornithological Applications 116:35–49. Leu, M., S. E. Hanser, and S. T. Knick. 2008. The human footprint in the west: A large- scale analysis of anthropogenic impacts. Ecological Applications 18:1119-1139. Knick, S. T., D.S. Dobkin, J. T. Rotenberry, M. A. Schroeder, W. M. Vander Haegen, and C. van Riper III. 2003. Teetering on the edge or too late? Conservation and research issues for avifauna of sagebrush habitats. Condor 105:611-634. Knick, S. T., and J. W. Connelly (editors). 2011. Greater Sage-Grouse: ecology and con- servation of a landscape species and its habitats. Studies in Avian Biology Series (vol. 38), University of California Press, Berkeley, CA. Kristan, W. B., III, W. I. Boarman, and J. J. Crayon. 2004. Diet composition of common ravens across the urban-wildlife interface of West Mojave Desert. Wildlife Society Bulletin 32:244-253. Lammers, W. M., and M. W. Collopy. 2007. Effectiveness of avian predator perch deter- rents on electric transmission lines. Journal of Wildlife Management 71:2752–2758. Lockyer, Z. B., P. S. Coates, and D. J. Delehanty. 2013. Greater Sage-Grouse nest preda- tors in the Virginia Mountains of northwestern Nevada. Journal of Fish and Wildlife Management 4:242–255. Manzer, D. L., and S. J. Hannon. 2005. Relating grouse nest success and corvid density to habitat: a multi-scale approach. Journal of Wildlife Management 69:110–123. Prather, P. R., and T. A. Messmer. 2010. Raptor and corvid response to power distribution line perch deterrents in Utah. Journal of Wildlife Management 74:796–800. Sauer, J. R., J. E. Hines, J. E. Fallon, K. L. Pardieck, D. J. Ziolkowski, Jr., and W. A. Link. 2014. The North American Breeding Bird Survey, Results and Analysis 1966 - 2012. Version 02.19.2014. USGS Patuxent Wildlife Research Center, Laurel, MD. Schroeder, M. A., C. L. Aldridge, A. D. Apa, J. R. Bohne, C. E. Braun, S. D. Bunnell, J. W. Connelly, P. A. Deibert, S. C. Gardner, M. A. Hilliard, G. D. Kobriger, S. M. McAdam, C. W. McCarthy, J. J. McCarthy, D. L. Mitchell, E. V. Rickerson, and S. J. Stiver. 2004. Distribution of sage-grouse in North America. Condor 106:363-376. Slater, S. J., and J. P. Smith. 2010. Effectiveness of raptor perch deterrents on an elec- trical transmission line in southwestern Wyoming. Journal of Wildlife Management 74:1080–1088. Welch, B. L. 2005. Big sagebrush: A sea fragmented into lakes, ponds, and puddles. Gen. Tech Rep. RMRS-GTR-144. Fort Collins, CO: U.S. Department of Agriculture, For- est Service, Rocky Mountain Research Station. 210 p. White, C. 2005a. Hunters ring the dinner bell for ravens: experimental evidence of a unique foraging strategy. Ecology 86:1057-1060. White, C. 2005b. Indirect effects of elk harvesting on ravens in Jackson Hole, Wyoming. Journal of Wildlife Management 70:539-545.

Patrick Magee, [email protected]

162 Colorado Birds Summer 2015 Vol. 49 No. 3 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 pix- els. 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 Colorado Birds photo editor, [email protected].

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

Contributors who are not members of CFO will, upon request, receive a complimen- tary copy of the issue of Colorado Birds in which their articles appear.

Colorado Birds Summer 2015 Vol. 49 No. 3 163 Fig. 1. Hermit Thrush, Higbees Beach Fig. 2. Ovenbird, Key Largo Ham- S. W. A., Cape May Co., NJ, 30 Oc- mocks, Monroe County, FL, 24 April tober 2010. Photo by Tony Leukering 2007. Photo by Christopher L.Wood

Fig. 3. Sprague’s Pipit, Eddy County, Fig. 4. Male MacGillivray’s Warbler, NM, 24 November 2007. Photo by Jerry Piceance Basin, CO, 1 July 2009 . Pho- Oldenettel to by Dona Hilkey

In the Scope Soft Parts: Leg Color in Passerines . . . 117

Fig. 5. Canyon Towhee, Pueblo West, Pueblo Co., CO, 25 November 2011. Photo by Loch Kilpatrick