Bird migration linked to predation pressure
26 January 2010
Arctic shorebirds travel thousands of miles to their breeding sites in the far north. A recent study finds that the substantial energy cost of such long migrations is balanced by higher survivability in a remote, harsh landscape.
Birds that nest in the Arctic risk long flights from their summer feeding grounds and exposure to extreme weather both along the way and upon arrival. Potential benefits of such a migration include more food availability, fewer parasites and less predation. Researchers attempted to find out if nest predation could play a key role.
The scientists monitored 1,555 artificial nests at seven breeding sites for at least two summers. The sites extended over 30? latitude. As expected, nest predation fell in higher latitudes: for every degree higher, predation dropped 3.6 percent for a total over the entire range of 65 percent. Although the link is clear, the researchers note that more study is needed to improve understanding of the ecology and evolution of long-distance migration. As the Arctic grows warmer, under the influence of natural and anthropogenic climate change, the implications for these “escapes” from predators could be serious.