American Robin subspecies (1 Viewer)

[tim.birdboy]

Among the 7 accepted subspecies of American Robin (Turdus migratorius), am I correct in believing that only two subspecies are found in Nebraska, T. m. migratorius and T. m. nigrideus? Or is T. m. achrusterus found as well? What is the best way to differentiate these three? Hood pattern? Thanks, hopefully there's an AMRO expert out there. :-O

tim.birdboy

 

[Xenospiza]

From Thrushes (Clement, Hathway, Byers, Wilczur, London: Christopher Helm, 2000).

I'd guess migratorius and propinquus are the likely forms in NE; nigrideus breeds in & around Quebec/Labrador and winters west to LA (could occur as a vagrant); achrusterus breeds south from OK east to VA (could occur as an overshoot).
I am not a big fan of North American subspecies, as most are clinal and ill-defined, but if you want to find out where the birds come from, the following fieldmarks should help.

migratorius: head black or blackish-grey, dark gray back, undertail coverts white, tail tip with white tip on 2-3 outer feathers (female paler, duller and borwner than male: this is generally the case in all forms).
Compared to migratorius:
nigrideus: darker, head blackish, mantle and back dark with dark centres on feathers, underparts darker, undertail coverts gray, heavily streaked chin, tail similar.
achrusterus: small; black on forehead to crown tipped pale gray or orange-brown, browner upperparts, white tips to tail rather indistinct, underparts somewhat paler.
propinquus: pale, hardly any white on tail, some females can almost lack any red on breast.

 

[tim.birdboy]

Thanks Xenospiza! That's a huge help! AMRO subspecies don't seem to be a very popular subject!