The brant or brent goose (Branta bernicla) is a small goose of the genus Branta. There are three subspecies, all of which winter along temperate-zone sea-coasts and breed on the high-Arctic tundra. The brant goose was strictly coastal bird in winter, rarely leaving tidal estuaries, where it feeds on eelgrass (Zostera marina) and the seaweed, sea lettuce (Ulva). On the east coast of North America, the inclusion of sea lettuce is a recent change to their diet, brought about by a blight on eelgrass in 1931. This resulted in the near-extirpation of the brant. The few that survived changed their diet to include sea lettuce until the eelgrass eventually began to return. Brants have maintained this diet ever since as a survival strategy. A similar collapse in eelgrass in Ireland in the 1930s also negatively impacted the population. In recent decades, it has started using agricultural land a short distance inland, feeding extensively on grass and winter-sown cereals. (Source: Wikipedia.org, CC BY-SA)