Monday, 2 March 2015

B.O.T.D. Magnolia Warbler

B.O.T.D. Mar 2, 2015

Magnolia Warbler (Dendroica magnolia)

Migrating overland at night was part of the cycle of nature on before man learned to put bricks and mortar together. But night flying has grown increasingly dangerous for birds because of the proliferation of tall structures and confusing lights across the landscape. A harbinger of things to come was noted more than half a century ago by an observer who spent one foggy night in the torch of the Statue of Liberty and watched as songbirds streamed by like a "swarm of bees." The silence was broken by intermittent thuds as birds "struck the light with terrific impact," many of them suffering fatal injuries.

Television transmitting towers present a special hazard. Close monitoring showed that a single tower in northwest Florida killed nearly 2000 birds during each of three autumn migrations. One of the hardest-hit species was the magnolia warbler; after just one night, 106 were found dead. Such wholesale carnage is most common when tall, illuminated structures are shrouded in foggy weather, which diffuses the light and blots out any other points of reference. In 1954, drizzle blanketed an area from Canada to the Gulf of Mexico during three nights of heavy songbird migration. On the mornings after, surveys in 25 localities identified some 10000 victims - only a fraction of then total. Of those, nearly one-tenth were magnolia warblers; how many more of their ill-fated kind perished on those three terrible nights will never be known.