Snowy owl tracking discovers unsuspected behaviour – Winter on the icepack

Tracking snowy owls in northern Canada. Credit Andrew Maher.

December 2008. "Six of the adult females that we followed in a satellite study spent most of last winter far out on the Arctic sea ice," says Quebec University doctoral student Jean-Francois Therrien. Therrien is working with Professor Gilles Gauthier as part of an International Polar Year (IPY) research project to better understand key indicator species of Canadian northern ecosystems, and their findings could lead to a rethink of the snowy owl's place in the North American ecosystem.

The behaviour of the owls is a mystery to scientists. Gilles Gauthier said "It is possible that the owls were preying on seabirds. Bird researchers at coastal field sites have observed snowy owls attacking eiders in winter. This hypothesis will be strengthened if we can match up the locations of our birds with the position of open water leads in the ice, as recorded by other satellite data."

The owls flew huge distances
The biologists are now keen to find out if Inuit seal hunters ever encounter the large white birds on the ice in winter darkness, as they are trying to grasp the range of the owls from year to year. Therrien stressed the unusual distances the birds migrated from where they were banded on their nesting grounds on Bylot Island, north of Baffin Island. He said "The satellite data showed just how dramatic the owl movements are. They flew huge distances. One owl went to Ellesmere Island, another flew straight to North Dakota and a third ended up on the eastern point of Newfoundland."

Snowy owl chicks. Credit Jean-Francois Therrien.

"We had the largest abundance of lemmings in many years in our study area this past summer," said Gauthier. "The owls had no problems raising young, so we were informally predicting a strong outward movement of young owls this winter."

And judging by numerous newspaper reports and sightings, that prediction has already proved accurate.

Gauthier added "The support from IPY and Canada's Natural Sciences and Engineering Research Council (NSERC) and the advances in satellite technology have given a huge impetus to what promises to be a revolution in our understanding of this key northern species." The researchers believe that this knowledge can't come soon enough.

Satellite tracker fitted to a snowy owl. Credit Giles Gauthier.