Ecology. Bird navigation--computing orthodromes.

Abstract

There are many theories about how migrating birds navigate as Wehner explains in his Perspective. He discusses new findings obtained with radar on a Canadian coast guard icebreaker vessel, which show that Arctic seabirds are able to faithfully follow the great-circle (orthodrome) routes of far northern latitudes most probably by steering with their sun compass while keeping their internal clock out of phase with local time (Alerstam et al.).