NYC Area Analysis – 11-12 September

Andrew Farnsworth The Cornell Lab Sep 12, 2012

Migration was generally light across much of the great New York City metropolitan area on the night of 11-12 September. High pressure off the Atlantic coast brought warmer evening conditions than either of the previous two nights, as well as calm and even light southerly winds; after such favorable conditions during previous nights, migration was noticeably less evident. However, despite the light migration, the presence of extremely powerful lights at the Tribute in Light, a memorial to those lost on September 11, 2001 attracted many hundreds of birds to lower Manhattan. During peak periods of attraction, 1000-2000 birds were visible circling in the beams of light. Birds illuminated from these powerful lights were visible from quite a distance, appearing like bright snowflakes or white confetti slowly fluttering in a breeze. From a vantage at the Empire State Building earlier in the evening, birds were circling at many altitudes, from near ground level up to approximately 1500 meters. Small songbirds represented greater than 95% of the birds aloft in the lights – these included American Redstart, Ovenbird, Black-and-white, Canada, Magnolia, Blackpoll, and Chestnut-sided Warblers, Common Yellowthroat, Northern Waterthrush, and Northern Parula. ¬†Additionally, several species of thrushes, including Swainson’s and Wood Thrush and Veery, Scarlet Tanager, Rose-breasted Grosbeak, and Baltimore Oriole rounded out the list of some of the land birds seen in the lights. Several Green Herons, a Laughing Gull, three unidentified cuckoos, a small rail, and several Common Nighthawks were also present. These larger bodied birds stood out in the sea of small songbirds in the illuminated areas. A single Peregrine Falcon was also hunting migrants as they circled in the lights, making several spectacular and successful dives into the migrant swarm.

Light migration in the Northeastern US on 11-12 September, as seen in a mosaic of weather surveillance radar imagery