Earlier Snow Melt from Climate Change Impacts Breeding of Arctic Birds

It turns out that climate change may be impacting the breeding of Arctic birds. Scientists have found that migratory birds that breed in Arctic Alaska are creating their nests earlier in the spring in response to earlier snow melt.

In order to better understand the breeding patterns of Arctic birds and see whether their patterns were changing, the researchers looked at nearly 2,500 nests of four shorebird species and one songbird. These species included the semi-palmated sandpiper, the red phalarope, the red-necked phalarope, the pectoral sandpiper, and the Lapland longspur. The scientists recorded when the first eggs were laid in each nest.

Then, the scientists assessed the snow melt in nesting plots at different intervals in the early spring. The researchers also examined predator abundance and satellite measures of the seasonal flush of new growth of vegetation in the tundra. In the end, the scientists found that the most important factor that determined when the birds were nesting was snow melt.

"It seems clear that the timing of the snow melt in Arctic Alaska is the most important mechanism driving the earlier and earlier breeding dates we observed in the Arctic," said Joe Liebezeit, one of the researchers, in a news release. "The rats 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."

In fact, the birds advanced their nesting at an average of four to seven days over the nine years of the study. This pattern agrees with the general observation of .5 days per year, which has been seen in other studies of nest initiation in the Arctic.

"Migratory birds are nesting earlier in the changing Arctic, presumably to track the earlier springs and abundance of insect prey," said Steve Zack, WCS Coordinator of Bird Conservation. "Many of these birds winter in the tropics and might be compromising their complicated calendar movements to accommodate this change. We're concerned that there will be a threshold where they will no longer be able to track the emergence of these earlier springs, which may impact breeding success or even population viability."

The findings are published in the journal Polar Biology.