ii8 NATURE-STUDY 



not be sufficient for so many birds. Others go to Mexico and 

 South America by flying over the mainland and the Isthmus, 

 while still others fly from the Gulf States across the Gulf, 

 and not necessarily at its narrowest part either. This shows 

 that some birds are not averse to long flights over the water. 

 In their migrations birds are subject to many dangers. 

 Along the coast they are attracted by the lighthouses at night, 

 and beat themselves to death against the shining beacons. 

 Storms, rain, sleet, and cold often destroy thousands of them. 

 Many flocks are exhausted and drown in the seas they at- 

 tempt to cross. 



Mr. W. W. Cooke writes in the 1903 "Yearbook of the 

 United States Department of Agriculture" of the Eastern 

 nighthawk migrating 5,000 miles from Alaska to Patagonia, 

 and the American golden plover going from within the Arctic 

 Circle to the southern part of Argentine, a distance of 8,000 

 miles. He also gives interesting estimates of the rate of 

 travel. The average speed in the northward migration in 

 the spring from the Southern States to Minnesota is about 

 23 miles per day, increasing more and more after this, to 

 40 miles through Minnesota, and to 70 or more miles farther 

 north. The reason for this increase is that the season ad- 

 vances more rapidly farther north. He states that most 

 birds that winter south of the United States outstrip the 

 spring in its advance, but that the robin advances more 

 slowly than spring. 



In the warm South the birds spend the winter and enjoy 

 themselves. But on the return of spring they go north to 

 breed. Northern latitudes seem better for the breeding, 

 and many birds build their nests far north in Alaska, the 

 Mackenzie Valley, Labrador, and even in Greenland. The 



