Climate change prompting Arctic birds to breed early

Earlier spring seasons and snow-melt brought about by climate change are causing migratory birds that breed in the Arctic Alaska to breed sooner, says a study.

"It seems clear that the timing of the snow melt in the Arctic Alaska is the most important mechanism driving the earlier and earlier breeding dates we observed in the Arctic," said Joe Liebezeit from Audubon Society of Portland in the US.

Researchers looked in nearly 2,500 nests of four shorebird species semi-palmated sandpiper, red phalarope, red-necked phalarope, and pectoral sandpiper, and one songbird, the lapland longspur, and recorded when the first eggs were laid in each nest.

Snow-melt was assessed in nesting plots at different intervals in the early spring. Other variables, like nest predator abundance (which is thought to affect timing of breeding), and satellite measures of "green-up" (the seasonal flush of new growth of vegetation) in the tundra were also assessed as potential drivers of the change in nest timing. But these were found to be less important than snow-melt.

"The rates of advancement in earlier breeding are higher in Arctic birds than in other temperate bird species, and this accords with the fact that the Arctic climate is changing at twice the rate," Liebezeit added.

The study appeared in the online edition of the journal Polar Biology.