This page is devoted to variation in American
Robin (Turdus migratorius). The vast majority
of birds fall within the range of limited variation described
in most references:- eastern birds average darker, western paler;
western birds normally have much-reduced white tail corners; a
small number of the paler (presumed western) birds exhibit a pale
supercilium plus more extensive white on the underparts that can
narrowly divide the red belly and lower breast.
Here are some individuals that perhaps push the envelope a little
further; all are from Fort Worth, Texas, and all but the first
bird are digiscope images:-
1) Winter 1999: sadly I could not get a profile shot of this bird,
as it had a striking supercilium that extended back beyond the
rear of the auricular. It otherwise looked fairly normal - i.e.it
was not a pale bird, thus demonstrating that the eyebrow effect
can occur in normally-colored individuals:
2) Jan 13, 2003: This individual was normal in every other respect,
other than the irregular supercilium present on both sides of
the head - again showing that normal-color birds can have a prominent
eyebrow:
3) Jan 13, 2003: This bird shows how the apparent supercilium
can be exaggerated by a front-view. This individual has the palest
head/upperparts that I've noted thus far, and also was the first
AMRO on which I noticed a diffuse brown chest band (in the manner
of Varied Thrush):
4) Jan 13, 2003: This bird also has a diffuse brown chest band,
and also shows very little contrast on the rump/uppertail coverts;
finally, it looks rather short-tailed and "petite" (especially
in the back shot) - instead of the normal robust "feel"
of AMRO:
5): Jan 13, 2003: A most interesting bird:- note the extensive
grayish brown wash on the chest below the throat that mostly obsures
the underlying red color, and the extent of white on the breast;
if this individual also sported a supercilium, it could easily
lead an observer to think about Eyebrowed Thrush (Turdus obscurus):
6) Jan 27, 2003: At each end of the continuum, these birds look
very different from each other, and at a distance the right bird
could be taken for something more exotic:
- closer looks show it is clearly an American Robin - but with
much reduced red on the underparts, and with an obvious, blotchy
gray-brown wash on the chest:
- the same bird in Feb 4, 2003; note how from this angle the breast
looks VERY odd!; had this one photo been submitted as something
more exotic, it might have given reviewers a few problems:
