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. It has been suggested that they learnt this behaviour by following other species of geese. Food resource pressure may also be important in forcing this change, as the world population increased over 10-fold to 400,000-500,000 by the mid-1980s, possibly reaching the carrying capacity of the estuaries. In the breeding season, it uses low-lying wet coastal tundra for both breeding and feeding. The nest is bowl-shaped, lined with grass and down, in an elevated location, often near a small pond. The brant goose is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds applies. Etymology Branta is a Latinised form of Old Norse brandgás, "burnt (black) goose", and bernicla is the medieval Latin name for the barnacle. The brant and the similar barnacle goose were previously considered one species, formerly believed to be the same creature as the crustacean. That myth can be dated back to at least the 12th century. Gerald of Wales claimed to have seen these birds hanging down from pieces of timber, William Turner accepted the theory, and John Gerard claimed to have seen the birds emerging from their shells. This myth arose because in the 1100s the migration of birds was unknown, but it was known that none of these birds was ever seen nesting, nor were eggs found, nor were goslings seen. The legend persisted until the end of the 18th century. In County Kerry, until relatively recently, Catholics could eat this bird on a Friday because it counted as fish. References Further reading Millington, Richard (1997). Separation of Black Brant, Dark-bellied Brent Goose and Pale-bellied Brent Goose Birding World 10(1):11–15; an identification paper (this paper presented claims that Black Brant and Dark-bellied Brent Goose were interbreeding extensively in the Russian Arctic) Sangster, George (2000). Taxonomic status of bernicla and nigricans Brent Goose British Birds 91(12):565–572 (a critical re-evaluation of the claims