Ninety per cent of Norway’s two million pairs of cliff-nesting seabirds are located in nesting colonies above the Arctic Circle. But why are these colonies located exactly where they are?
Using computer models to describe ocean currents and the transport of floating fish larvae, researchers were able to show that bird colonies are located in areas where currents and the shape of the coastline cause fish larvae to concentrate.
More simply stated, “the birds are where the food is,” said Hanno Sandvik, a biologist from the Centre for Biodiversity Dynamics at the Norwegian University of Science and Technology (NTNU) and first author of a paper published in Nature Communications on Friday.
This may seem like a self-evident fact, but the research team is the first ever to be able to essentially predict where seabird colonies should be, based on fish larvae “hot spots” that show up in computer models of how fish larvae are transported along the coast.
Sandvik also found that colony locations were strongly associated with locations where fish larvae concentrations had a high minimum level across many years. If an area along the coast had very high levels of fish larvae concentrations, but if those levels were not consistent over the years, then a colony was less likely to be associated with that spot.
“Birds prefer places where the (prey) numbers are as stable as possible,” Sandvik said. “The best places are where you have enough fish larvae every year.”
shared via: www.sciencedaily.com/releases/2016/05/160513083144.htm
article: Nancy Bazilchuk
photo: Per Harald Olsen, NTNU