annual migratory flights over 2,000 miles nonstop across the ocean. 



Night travel is probably best for the majority of birds chiefly from 

 the standpoint of feeding. Digestion is very rapid in birds and yet the 

 stomach of one killed during the day almost always contains food. To 

 replace the energy required for long flight, it is essential that either 

 food be obtained at comparatively short intervals or stores of fat be 

 laid on prior to migration. If the smaller migrants were to make 

 protracted flights by day they would arrive at their destination at 

 nightfall almost exhausted, but since they are entirely daylight 

 feeders, they would be unable to obtain food until the following 

 morning. Unless reserve energy was carried in the form of fat, the 

 inability to feed would delay further flights and result in great 

 exhaustion or possibly even death should their evening arrival 

 coincide with cold or stormy weather. By traveling at night, they can 

 pause at daybreak and devote the entire period of daylight to 

 alternate feeding and resting. This schedule permits complete 

 recuperation and resumption of the journey on a subsequent evening 

 after sufficient energy has been restored. 



The day migrants include, in addition to some of the ducks and 

 geese, the loons, cranes, gulls, pelicans, hawks, swallows, 

 nighthawks, and swifts. Soaring birds, including broad-winged 

 hawks, storks, and vultures, can only migrate during the day because 

 their mode of flight makes them dependent on up-drafts created by 

 heat from the sun for their long distance travels. On the other hand, 

 swifts and swallows feed entirely on diurnal flying insects. The 

 circling flocks are frequently seen in late summer feeding as they 

 travel while working gradually southward. Formerly, great flocks of 

 red-tailed, Swainson's, and rough-legged hawks could be seen 

 wheeling majestically across the sky in the Plains States. In the East, 

 good flights of broad-winged, Cooper's, and sharp-shinned hawks are 

 still often seen, particularly along the Appalachian ridges. 



Because many species of wading and swimming birds are able to 

 feed at all hours, they migrate either by day or night and are not 

 accustomed to seek safety in concealment. Some diving birds, 

 including ducks that submerge when in danger, often travel over 

 water by day and over land at night. Strong flyers like the snow geese 

 can make the entire trip from their staging area in James Bay, 

 Canada, to the wintering grounds on the Louisiana Gulf coast in one 

 continuous flight. These birds are seldom shot by hunters enroute 

 between these two points but are often observed, when migrating, by 

 aircraft pilots. Graham Cooch of the Canadian Wildlife Service 

 tracked a flight of the blue phase of this species in 1955. The birds left 

 James Bay on October 17 and arrived on the Gulf coast 60 hours later 

 after an apparent continuous flight over the 1,700-mile route at an 

 average speed of 28 miles per hour. Golden plovers, likewise, 

 probably make the southward flight from the Arctic to the South 

 American coast in one giant leap. Other Arctic species on their 

 northward flight in the spring might prefer to fly at night in lower 

 altitudes, but must necessarily fly during the day at higher altitudes 



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