Someone sent me the responses on the bird list about the Jones Beach Gyrfalcon.
There seems to be a bit of controversy, I stated a few days ago to Hugh that it
was absolutely a young gray morph Gyrfalcon. However, I thought it was obvious
and did not give reasons why. My mistake, since it is necessary on such an
uncommonly encountered species.
First off the color of juvenile gray Gyrfalcons is browner on top than a
Peregrine (which often shows a slaty-brown tone to the upperside....note that
juv dark Gyrs can be slaty-brown on top), also the malar mark is narrow (along
with the lack of a white cheek spot shown by most Peregrines and almost all
wild Tundrius birds), the spotting to the remiges and tail are much less
distinct (especially the topside of the tail), the head lacks a pale crown, the
underwing coverts are less 'checkered', the chest is not whiter than the body
(as is with most juv Peregrines), the flanks show a less "barred" appearance
than Peregrine, and also almost all juv Peregrines show "V" or diamond-shaped
markings to the undertail coverts (Gyrs are typically streaked).
On shape, the body is plump, the wings are stocky and less sharply tapered, and
the tail is long compared to Peregrine. These differences are slight but
evident on all Gyrs. The point of P9 being longer than P10 is not always
accurate, some Peregrines show this (I have photos of it). I may have left some
stuff out without going through photos at the moment, and there are also a few
other traits that separate the two species but I will leave that for my next
book.
There is incredible variation in Peregrine and Gyrfalcon plumages, in my
studies of Gyrfalcon I have seen birds that are "in-betweeners" as far as
morph. There are paler gray morphs that approach the paleness of white morphs
and darker gray morphs that lean towards dark morph, etc. Also, Anatum and
Peale's Peregrines resemble a Gyr in plumage more so than Tundrius, so that
discussion would have been more appropriate.
Falconry hybrids occur of course, but this bird is not one of them. There are
no jesses, bells, or rings on the bird, and the plumage is typical (I would say
perfect in every way) for Gyrfalcon. Having said that, even hybrids can look
like one parent and do not always take a "mix" of traits from both parents. So,
if this were a hybrid it would be impossible to tell based on plumage.
Feel free to post this response, I hope it helps, and hope the bird sticks
around for people,
Jerry Liguori
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