[cobirds] Re: Gyrfalcon on Trilby Road s of Larimer Landfill on 2/18/2020 (Larimer)
Nice to see some discussion of this. When I saw the Gyrfalcon a week or so ago, it caught and began feeding on what I presumed was a meadowlark. While feeding, it was buzzed by another very similarly sized falcon. The other falcon disappeared almost immediately, so I was unsure of what it was, but assumed it was a Prairie Falcon (though of course couldn't help but wonder that it seemed very similar in size and general pattern/coloration). Good to know that there is definitely a similar size and plumaged Prairie Falcon in the area, chasing other birds for meadowlarks, as well. -- 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 cobirds+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/846de25f-4096-4031-9f4b-3f701309ea37%40googlegroups.com.
[cobirds] RE: Gyrfalcon on Trilby Road s of Larimer Landfill on 2/18/2020 (Larimer)
A nice analysis by Dave Leatherman. I'd also point out that part of what gives Prairie Falcons a dark-armpitted look in flight, the contrastingly dark flanks, is also quite apparent while perched. This is demonstrated well by Dave's images; compare the even streaking/barring through the Gyrfalcon's underparts to the Prairie Falcon's denser-streaked flanks. David Tonnessen -- 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 cobirds+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/42601d36-386f-44f3-a4d0-ad9e26966046%40googlegroups.com.
[cobirds] RE: Gyrfalcon on Trilby Road s of Larimer Landfill on 2/18/2020 (Larimer)
Dave, thank you for your excellent comparison of markings, a fine discussion and the two helpful photographs. If I may further add to your description, as a falconer and someone who has worked with males and females of both species: I've been told by several experienced raptor watchers who've seen the Ft. Collins gyrfalcon in person that it is a male. If the prairie falcon appears to be about the same size when looking through binoculars, or even with the naked eye, then it is likely a female. The healthy flying weight of a female prairie falcon is in the range of 27-30 oz. The equivalent for a male gyrfalcon ranges from about 32-37 oz. Two falcons so close in weight would almost certainly appear to be the same size when viewed perched on a pole, etc. My point being, this can definitely be a tough call if lighting and other conditions aren't ideal…and both falcons are very close in size. Good birding to all, ~Anne Price Littleton, JeffCo -- 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 cobirds+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/CY4PR07MB2743B7A286CD98CFBF68C051CF100%40CY4PR07MB2743.namprd07.prod.outlook.com.
