[Mystery bird] Marbled Godwit, Limosa fedoa, photographed at Galveston Island East Beach, Texas. [I will identify this bird for you in 48 hours]
Image: Joseph Kennedy, 1 June 2010 [larger view].
Nikon D200, Kowa 883 telescope with TSN-PZ camera eyepiece 1/1000s f/8.0 at 1000.0mm iso400.
Please name at least one field mark that supports your identification.
This species is comprised of a seemingly homogeneous population of birds. However, scientists have recently found that this species shows some geographic variation between breeding populations, can you tell me what that variation is?
ANSWER: Measurements of the two Alaska-breeding populations shows these birds have shorter wings and legs than the Great Plains-breeding birds. This paper went on to say this of the most diminutive subspecies of Limosa fedoa:
This limited Alaskan-breeding population … named Limosa fedoa beringiae … does not appear in the guide-books (Shorebirds, Sibley etc.) or on the maps, and may only differ in size (e.g.; shorter bill, wing and legs), but a lone male beringiae amongst a bunch of female fedoa could look tiny.
L. f. beringiae probably normally winters along the coast of Oregon and northern California amongst the more numerous [nominate] fedoa. No plumage differences are yet described, but the climate anomaly and geographical distribution (which may include a long over-ocean flight) may throw up some plumage and moult differences, perhaps worthy of extra study.
Daniel D. Gibson & Brina Kessel. (1989). Geographic Variation in the Marbled Godwit and Description of an Alaska Subspecies. The Condor 91:436-443 [free PDF].