DAILY FLIGHT TIMING AND MOVEMENT STRATEGIES OF MIGRATING LANDBIRDS: IMPORTANCE OF LOCAL WIND PATTERNS

Although weather variation is known to affect migratory behaviours of landbirds, the specific effects of winds on flight timing and orientation at ecological barriers are not well understand. To assess seasonal effects of winds on flight timing at Long Point, Ontario, I compared estimates of daily arrival and departure to nocturnal radar counts. Landfall occurred later on nights with unfavourable versus favourable winds, and later on nights in spring versus fall. Daily arrival was positively associated with radar counts on nights with NE and SW winds, but variably associated otherwise. Departure timing could not be assessed. To investigate effects of winds on flight orientation, I tested whether migration proceeded in a broad front among four coastal sites in southwest Nova Scotia. There was variation among sites and broad front migration partly depended on wind. These results support that winds influence migratory behaviours at a regional scale