Stable Isotope Analysis Supports First Occurrence of a Wild-Origin Greylag Goose (Anser anser) to Make Landfall in North America

Abstract

In North America, the Greylag Goose (Anser anser) has been added to the list of vagrant North American waterfowl based on a bird observed in 2005 on a stationary oil ship in the Atlantic Ocean 167 km southeast of the island of Newfoundland, and on single birds observed in Connecticut and Nova Scotia in 2009 and 2010, respectively. Here, feather and toe-claw hydrogen isotope values (δ2H) linked to spatial hydrological hydrogen isotope patterns are used to demonstrate the origin of the first probable wild-origin Greylag Goose known to make landfall in North America. The bird in question, shot by hunters on Grand Manan Island, New Brunswick, in December 2007 and subsequently deposited at the New Brunswick Museum (specimen NBM 11143), was identified as Anser anser and potentially a wild-origin bird. Isotope data indicates the bird is of probable Greenlandic origin. This supports and pre-dates recent (2014) reports of the Greenlandic molting of Icelandic Greylag Geese, until recently believed to molt exclusively on Iceland. Greylag Geese recorded in North America appear to be part of a pattern of increasing numbers and diversity of geese of northeastern Atlantic origin detected in eastern North America in recent decades.