Ross's Snow Goose
/My list of shots to strive for when visiting Bosque del Apache NWR in New Mexico always includes ones that distinguish between Ross's Goose (Chen rossii) and Snow Geese (Chen caerulescens). But invariably, the Sandhill Cranes, raptors, many species of ducks and other birds capture my attention and I return home with this item on the list unchecked....until my most recent visit in January 2018.
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Ross's and Snow Goose
The Ross's Goose (front) is smaller than the juvenile Snow Goose (back). The bill of the Ross's is shorter and stubbier and the upper mandible has bluish caruncles (wartty bumps).
D500, 500mm f/4 lens with 1.4x teleconverter, handheld
1/3200 sec at f/7.1, ISO 450
Snow and Ross's Geese
This is the only presentable image I had that distinguishes between Snow and Ross's before the January visit to Bosque. The larger Snow Goose is in front with two Ross's following closely behind. Note that the wide bevelled gap between the mandibles ("grin patch") of the Snow Goose is either lacking or much narrower in the Ross's. This will become more apparent in subsequent images.
D300s, 500mm f/4 lens, handheld
1/1000 sec at f/8, ISO 400
Ross's and Snow Geese
Ross's (four) and Snow (one, top left) Geese in flight. Note the difference in size of the "grin patch."
D500, 300mm f/4 with 1.4x teleconverter, handheld
1/3200 sec at f/8, ISO 1600
Ross's Goose in flight
D500, 500mm f/4 lens with 1.4x teleconverter, handheld
1/2500 sec at f/6.3, ISO 360
Ross's Goose in fight
D500, 500mm f/4 lens with 1.4x teleconverter, handheld
1/2500 sec at f/6.3, ISO 400
Ross's Geese in flight
D500, 500mm f/4 lens with 1.4x teleconverter, handheld
1/2500 sec at f/6.3, ISO 360
Ross's Goose in flight
A better look at the caruncles on the upper mandible.
D500, 500mm f/4 lens with 1.4x teleconverter, handheld
1/2500 sec at f/9, ISO 1100
Six Ross's Geese in flight