Warming Arctic 'halts migration'
By Mark Kinver, Science and environment reporter, BBC News Milder winters in the Arctic region have led to fewer Pacific brants, a species of sea goose, migrating southwards, say researchers. A study by the US Geological Survey (USGS) found that as many as 30% of the birds were overwintering in Alaska rather than migrating to Mexico. Until recently, more than 90% of the species were estimated to head south. Writing in the journal Arctic, the team said the shift coincides with warming in the North Pacific and Bering Sea. “This suggests that environmental conditions have changed for one of the northernmost wintering populations of geese,” said lead author David Ward, a USGS researcher at the Alaska Science Center. … The authors added that the shift in climate after 1976 had well-documented effects on marine species, such as fish and seals, but estuarine species – such as the brant – had not been recorded. “Our study suggests that the growth in the brant population wintering on the Alaska peninsula is linked to the same climate change,” Mr Ward observed. …
