Monument so brilliantly, airplane pilots noticed that it could be seen 

 for 40 miles on a clear night. It is certain there is an extensive area of 

 illumination, and on dark nights with gusty, northerly winds, 

 nocturnal migrants seem to fly at lower altitudes and are attacted to 

 the Monument. As they mill about the shaft, they are dashed against 

 it by eddies of wind, and hundreds have been killed in a single night. 



In September 1948, bird students were startled by news of the 

 wholesale destruction of common yellowthroats, American redstarts, 

 ovenbirds, and others against the 1,250-foot-high Empire State 

 Building in New York City, the 491-foot-high Philadelphia Saving 

 Fund Society Building in Philadelphia, and the 450-foot-high WB AL 

 radio tower in Baltimore. In New York, the birds continued to crash 

 into the Empire State Building for 6 hours. 



More recently, the television tower has become the chief hazard. 

 These structures are so tall, sometimes over 1,000 feet, they present 

 more of a menace than buildings or lighthouses. Their blinking lights 

 cause passing migrants to blunder into guy wires or the tower itself 

 while milling around like moths about a flame. Numerous instances 

 (e.g. Stoddard and Norris 1967) throughout the U.S. indicate this 

 peril to migration is widespread. The lethal qualities of airport 

 ceilometers have been effectively modified by conversion to 

 intermittent or rotating beams. 



Exhaustion 



Both soaring and sailing birds are so proficient in aerial 

 transportation that only recently have the principles been 

 understood and imitated by aircraft pilots. The use of ascending air 

 currents, employed by all soaring birds and easily demonstrated by 

 observing gulls glide hour after hour along the windward side of a 

 ship, are now utilized by man in his operation of gliders. Moreover, 

 the whole structure of a bird makes it the most perfect machine for 

 extensive flight the world has ever known. Hollow, air-filled bones, 

 together with feathers, the lightest and toughest material known for 

 flight, have evolved in combination to produce a perfect flying 

 machine. 



Mere consideration of a bird's economy of fuel or energy also is 

 enlightening. The golden plover probably travels over a 2,400-mile 

 oceanic route from Nova Scotia to South America in about 48 hours of 

 continous flight. This is accomplished with the consumption of less 

 than 2 ounces of body fat (fuel). In contrast, to be just as efficient in 

 operation, a 1 ,000-pound airplane would consume only a single pint of 

 fuel in a 20-mile flight rather than the gallon usually required. 

 Similarly, the tiny ruby- throated hummingbird weighing approx- 

 imately 4 grams, crosses the Gulf of Mexico in a single flight of more 

 than 500 miles while consuming less than 1 gram of fat. 



One might expect the exertion incident to long migratory flights 

 would result in arrival of migrants at their destination near a state of 

 exhaustion. This is usually not the case. Birds that have recently 

 arrived from a protracted flight over land or sea sometimes show 



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