CONCENTRATED MIGRATORY MORNING FLIGHT AT LAKE PONTCHARTRAIN, LOUISIANA, USA

摘要

I describe large volume morning flights of migrant songbirds in autumn along the south shore of Lake Pontchartrain, Louisiana, USA. These flights have at times exceeded 10,000 birds/hr since their discovery in 2002, ranking the site among the continent's highest volume regular migratory songbird concentration locations. Migrants move in ' 'reverse'' direction northeastward up a peninsula in Lake Pontchartrain, and fly across a 9-km water gap to reach the north shore, usually struggling into a headwind. Flights are dominated by Yellow and Yellow-rumped warblers (Dendroica petechia and D. coronata), Eastern Kingbird (Tyrannus tyrannus), Indigo Bunting (Passerina cyanea), Cedar Waxwing (Bombycilla cedrorum), and American Robin (Turdus migratorius) during their respective migratory peaks. These species have exceeded 800 birds/hr, and 70 other small landbird species have been recorded. Flights of > 100 birds/hr were more frequent after nights with more hours of northerly winds.