Constant Compass Orientation For North American Autumnal Migrants

Document Type


Publication Date

Spring 1991

Published In

Journal Of Field Ornithology


Autumnal migrant flights were simulated from central North America to the Atlantic coast. Synoptic weather conditions associated with major S and SE bird migrations observed with radar were used to create a wind matrix for the simulation. Constant compass orientation was found to be a tenable strategy for the continental as well as the transatlantic portion of migration from North to South America via the western North Atlantic. Selection of wind conditions and heading were found to be more important than airspeed for trajectory of simulated tracks. Winds at 1500 m altitude offered shorter transit times than winds at 300 m and increased accuracy of orientation compared to winds at 5800 m. Although the simulation was restricted to S and SE migrants in eastern North America, it demonstrated the general importance of wind selection (as opposed to compensation for wind drift) for migratory strategy.