There seems to be a lot of confusion, for good reason, concerning separation of Rosy-Finch species. My frustration in attempting to separate these species at all sexes, ages and time of year - based on the most common field guide information has led me to do some research and I invite others to chime in on what I have found if you find that I have made some mistakes, omitted key information or have something to add.
Areas of confusion: · Many guides (Natl Geo, Sibley, Sibley, even Birds of NA [BNA]) often show pictures of breeding or 1st winter individuals, but not both, leaving you wondering just where the differences lie and when you should be looking for them. · When looking at the flock of ~500 that I have been viewing in Divide, CO recently, the overall variation doesn’t seem to fit the guides and leaves me wondering where to put the seemingly mass numbers of in-between individuals. · Sibley shows a variant brown-capped adult resembling a gray-crowned; but I cannot find any other guide or source that mentions such. · Some guides mention difficulty separating females of gray-crowned vs brown-capped; you are left wonder for what time of year and for what reasons. · The picture being used in my printed 1st edition copy of BNA for gray-crowned RF, sure looks like a black RF by any information I use, even that in the BNA doc itself. I don’t have an online subscription to BNA so I can’t check to see if it is still the same picture 10 years later. · No single guide shows you, with drawings/pics, the complete cycle and range (both sexes, and all molts, with the extremes in variation for each) for a species leaving you wondering where the gaps are and what you might be missing; and where the overlaps may or may not occur between species. So – after research, using Pyle, and the aforementioned guides and BNA printed 1st edition; I have synthesized the information into the following identification tips. Notes for separation: · One molt annually for all species and should be complete by early November for all species. Basic I plumage includes all body feathers. This means that head patterns should be consistent and complete. No need to consider imm or juv plumages for head patterns in December – information not obvious in the field guides. Differences in male vs female would be more along the line of intensity of color and pattern. Spring plumage due to feather wear instead of molt. o Basic I plumage (1st year birds) can be separated from Definitive Basic via non-body-feathers wear and shape if interested – but not necessary for species separation. · Head pattern should be a consistent diagnostic for all three species; across sexes. o Any bird without a distinct, non-diffuse gray band from eye and completing around the occiput (back of head) would be brown-capped. § Notes: brown-capped vary extensively in the amount of distinct cap being shown (from males having distinct cap and females to non-distinct to barely noticeable); and diffusing into a nape of brown or gray without a distinct gray band. Females can be quite gray overall; but without distinct gray band as noted above. o Any individual with a distinct, non-diffuse, with clear borders, gray (sometimes described as more silvery than gray) band would be either a gray-crowned or black rosy-finch. § An individual which is blackish on upper mantle and upper breast will be a Black RF if its cheek (auricular) is easily separated from its gray band; distinct different (blackish, grayish) color. Otherwise it is considered a gray-cheeked (coastal, northwestern) group of gray-crowned. § An individual with brown cheeks is a brown-cheeked (interior) group of gray-crowned RFs. This is my take after as much research as I am willing to put into it and time will allow. I am certainly capable of making outright mistakes (making no claims that I am an authority or anyone other than having put in a couple hours researching this) and would love to hear any evidence in support of, or contrary to my conclusions above. If you’ve read this far, perhaps you have some. J p.s. It turns out, that after doing this research and with this knowledge in hand, and then re-checking the major field guides (considering space considerations etc that the publishers must have) I might have done the same thing that they have done (with the odd exception of Sibley’s variant breeding brown-capped). It is just that, how it is presented leaves one wondering where the overlaps lie and how to draw the boundaries in one’s identification process. Perhaps you had or did not have this same issue as I. Jeff J Jones ( <mailto:[email protected]> [email protected]) Teller County - 8500' - Montane Woodlands -- 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]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/cobirds?hl=en.
