In 2012, Dick Schottler and I found a leucistic RTHA during the Denver CBC. It so happens that we found this bird in my neighborhood, which is on the western edge of the count circle. I was fortunate enough to watch this bird, likely a female (she was bigger than any other RTHA that tried to consort with her) up through 2020 when she disappeared. One thing I noticed over time was that she became whiter and whiter, although her red tail feathers remained distinct. I have a couple of photos if anyone is interested, but I have to say when I saw Ajit and Lisa's photos, my first thought was "wow, another leucistic red tail!" I also remember sometime back in the last year or two someone reporting on finding a leucistic RTHA corpse. All of which suggests that leucism is a bit more common than we may tend to think.
Ed Furlong Evergreen, CO On Tuesday, December 19, 2023 at 3:57:52 PM UTC-7 Ajit Antony wrote: > Hi Kevin and everyone else. > I looked up Brian K Wheeler's 'Birds of Prey of the East' ( this is the > first of his 2 books that came out, and I bought it when I was living in > New York). > He has a plate devoted to 'Albinos and other Variants,' Plate 34 where he > shows albinos and lucistic RTHA, where he says in a picture of a Eastern > partial albino that "Albinism affects wings and dorsal body surface more > commonly than ventral body surface and tail." > A few weeks ago we were at East 126th Avenue doing a raptor survey and we > did see a leucistic RTHA which had large splotchy white patches on its > dorsum as it flew, correctly IDd by Liza my wife and partner in the winter > raptor surveys that we do. > Ajit Antony > Central Park, Colorado > > On Tue, Dec 19, 2023, 10:21 AM '[email protected]' via Colorado Birds < > [email protected]> wrote: > >> Perhaps the mystery buteo is a leucistic Red-tailed Hawk? >> >> Kevin Corwin >> Centennial, Arapahoe County >> >> On Monday, December 18, 2023 at 9:06:48 PM UTC-7 [email protected] >> wrote: >> >>> December Winter Raptor Survey of Rocky Mountain Arsenal NWR and DIA >>> Raptor Alley, with sighting of a mystery buteo >>> >>> This is our 2nd season doing volunteer Winter Raptor Surveys (WRS) for >>> the Hawk Migration Association of North America (HMANA) since moving to >>> Denver in July 2022. Prior to moving we did 4 WRS in New York State in the >>> Hudson Valley area since 2016. >>> >>> Last winter season we did 3 surveys here – 1 in Denver and 2 in Boulder >>> in December 2022, and January and February 2023 for each route, following >>> it exactly, and roughly in the same week each month. >>> >>> This year we added another WRS in the area between Bennett and Jackson >>> Lake SP. We did that route a week ago with nothing special to report. It >>> may improve as winter progresses. >>> >>> Yesterday we completed the Rocky Mountain Arsenal to Barr Lake, and west >>> of Denver International Airport route for December 2023. >>> >>> We saw and identified 78 Raptors, including >>> >>> Ferruginous Hawk 5, all adult >>> >>> Prairie Falcon 1, which attacked a Red-tailed Hawk as >>> well as a Northern Harrier >>> >>> Bald Eagle 25 >>> >>> Northern Harrier 10 >>> >>> American Kestrel 5 >>> >>> Red-tailed Hawk 25, including 2 dark morph RT on Piccadilly >>> Road at Barr Lake, one perched and both in flight together. Spectacular. >>> >>> In addition we had a mystery buteo at 1st Creek at DEN Open Space >>> perched in a tree next to Peña Boulevard at 10:15 AM. When we finished our >>> survey and on the way back we could still see it (presumably the same >>> buteo) at the same location at 4:30 PM while driving south on Peña >>> Boulevard. >>> >>> Our eBird checklist for that location with images is: >>> >>> https://ebird.org/checklist/S156663182 >>> >>> My notes written during the observation were: The tail was reddish with >>> multiple equal width bands, no sub-terminal band, with more reddish >>> distally than proximally, as well the left side of the tail was slightly >>> more red than the right side of the tail which was less red. There was a >>> thin eyeline on an otherwise white head with a black blob in the malar >>> area, no belly band but a few speckles in the flank area, white scapulars >>> and coverts. >>> >>> >>> >>> Liza fancied a Krider's Hawk looking at the Raptor ID app. Looking at >>> Brian Wheeler's Raptors of Western North America at the time, I felt it >>> could be a juvenile light morph Harlan's Hawk, except today reading more >>> about it in his Birds of Prey of the East and looking at the pictures, the >>> back is not stark black and white as his images show. >>> >>> I sent the images to the WRS coordinator for expert opinions. So far one >>> opinion is that it could be a Krider’s Hawk or an intergrade between >>> Krider’s and an Eastern borealis Red-tailed Hawk. >>> >>> Any learned expert opinions with detailed reasons for your ID would be >>> most welcome. >>> >>> I have to admit that neither of us have ever seen any of these possible >>> species! Our ID speculations are book/image-based only. >>> >>> >>> You can see what we found on our previous WRSs along the same and other >>> routes at >>> >>> https://wrs.hmana.org/public_html/index.php as well as the 1 other >>> route developed in the past winter season in Colorado – the Nunn Raptor >>> Alley route conducted by Robert Beauchamp. Go to the website to the left >>> sidebar and click on Survey Map and enlarge it to Colorado, you can click >>> on individual surveys and using the drop-down menu, find previous survey >>> results. >>> >>> Anyone can develop their own survey route. It is open to all. You can >>> get more information at: >>> >>> https://www.hmana.org/winter-raptor-survey/ >>> >>> If you like raptors and know of an area with raptors you can develop >>> your own route, as long as it doesn’t overlap an established one. Just >>> follow the guidelines on the website. If you want any questions answered >>> you can email the WRS coordinator Janice Sweet. I can also be of help if >>> you want someone local. >>> >>> Ajit & Liza Antony >>> >>> Central Park, CO (which used to be called Stapleton) >>> >>> >>> >> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Colorado Birds" group. >> To post to this group, send email to [email protected] >> For more options, visit this group at >> http://groups.google.com/group/cobirds?hl=en?hl=en >> * All posts should be signed with the poster's full name and city. >> Include bird species and location in the subject line when appropriate >> * Join Colorado Field Ornithologists https://cobirds.org/CFO/Membership/ >> --- >> You received this message because you are subscribed to the Google Groups >> "Colorado Birds" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/cobirds/ae963d10-2ef1-41fd-bd3d-6b8c3cf89593n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/cobirds/ae963d10-2ef1-41fd-bd3d-6b8c3cf89593n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/cobirds?hl=en?hl=en * All posts should be signed with the poster's full name and city. Include bird species and location in the subject line when appropriate * Join Colorado Field Ornithologists https://cobirds.org/CFO/Membership/ --- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/fd79ba54-e9f3-4d02-b29a-bd63c2a22b80n%40googlegroups.com.
