PERILS OF MIGRATION 



The migration season is full of peril for birds. Untold thousands of 

 smaller migrants are destroyed each year by storms and attacks by 

 predatory animals. These mortality factors, and others, help keep 

 bird populations in check. Perils of migration are among these 

 causes. 



Storms 



Of all the hazards confronting birds in migration, particularly the 

 smaller species, storms are the most dangerous. Birds that cross 

 broad stretches of water can be blown off course by a storm, become 

 exhausted, and fall into the waves. Such a catastrophe was once seen 

 from the deck of a vessel in the Gulf of Mexico, 30 miles off the mouth 

 of the Mississippi River. Great numbers of migrating birds, chiefly 

 warblers, were nearing land after having accomplished nearly 95 

 percent of their long flight when, caught by a "norther" against 

 which they were unable to make headway, hundreds were forced into 

 the waters of the Gulf and drowned. A sudden drop in temperature 

 accompanied by a snowfall can cause a similar affect. 



Aerial Obstructions 



Lighthouses, tall buildings, monuments, television towers, and 

 other aerial obstructions have been responsible for destruction of 

 migratory birds. Bright beams of lights on buildings and airport 

 ceilometers have a powerful attraction for nocturnal air travelers 

 that may be likened to the fascination for lights exhibited by many 

 insects, particularly night-flying moths. The attraction is most 

 noticeable on foggy nights when the rays have a dazzling effect that 

 not only lures the birds but confuses them and causes their death by 

 collision against high structures. The fixed, white, stationary light 

 located 180 feet above sea level at Ponce de Leon Inlet (formerly 

 Mosquito Inlet), Florida, has caused great destruction of bird life even 

 though the lens is shielded by wire netting. Two other lighthouses at 

 the southern end of Florida, Sombrero Key and Fowey Rocks, have 

 been the cause of a great number of bird tragedies, while heavy 

 mortality has been noted also at some of the lights on the Great Lakes 

 and on the coast of Quebec. Fixed white lights seem to be most 

 attractive to birds; lighthouses equipped with flashing or red lights 

 do not have the same attraction. 



For many years in Washington, B.C., the illuminated Washington 

 Monument, towering more than 555 feet into the air, caused 

 destruction of large numbers of small birds. Batteries of brilliant 

 floodlights grouped on all four sides about the base illuminate the 



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