Possible Cackling Goose on Central Park reservoir

Last weekend a small goose was spotted amongst the Canadas. Variously posited as a Richardson's Cackling Goose, Branta h. hutchinsii, or the very similar Lesser Canada Goose, B. canadensis parvipes. Parvipes occurs further west than hutchinsii and is therefore statistically less likely to occur in New York.

Perhaps the most likely explanation, and the one currently favoured, is that it is a hybrid between hutchinsii and parvipes. There is apparently a fair amount of hybridisation where the two taxa overlap.

Features that point to hutchinsii include:

• Dusky breast
• Short stubby bill (though longer than the average, it seems to fall within the normal variation)
• Small size, maybe 60%-70% of the size on nearby Canadas
• Buffy throat patch.

Distribution of various subspecies of Cackling and Canada Goose. From the Sibley Guides website