X BIRDS OF AMERICA 



sustenance for land birds. The two areas of abundant food supply are North America and 

 northern South America, separated by the comparatively small areas of Mexico and Central 

 America, the islands of the West Indies, and the great waste stretches of water. 



The different courses taken by the birds to get around or over this intervening inhos- 

 pitable region are almost as numerous as the bird families that traverse them, and only some 

 of the more important routes will be mentioned here. 



Birds often seem eccentric in choice of route, and many do not take the shortest line. 

 The so species from New England that winter in South America, instead of making the 

 direct trip over the Atlantic involving a flight of 2,000 miles, take a somewhat longer route 

 that follows the coast to Florida and passes thence by island or mainland to South America. 

 What would at first sight seem to be a natural and convenient migratory highway extends 

 from Florida through the Bahamas or Cuba to Haiti, Porto Rico, and the Lesser Antilles 

 and thence to South America. Birds that travel by this route need never be out of sight 

 of land; resting places are afforded at convenient intervals and the distance is but little 

 longer than the water route. Yet beyond Cuba this highway is little used. About 25 species 

 continue as far as Porto Rico and remain there through the winter. Only adventurers of 

 some six species gain the South American mainland by completing the island chain. The 

 reason is not far to seek — scarcity of food. The total area of all the West Indies east of 

 Porto Rico is a little less than that of Rhode Island. Should a small proportion only of the 

 feathered inhabitants of the eastern States select this route, not even the luxuriant fauna 

 and flora of the tropics could supply their needs. 



A still more direct route, but one requiring longer single flights, stretches from Florida 

 to South America, via Cuba and Jamaica. The 150 miles between Florida and Cuba are 

 crossed by tens of thousands of birds of some 60 different species. About half the species 

 take the next flight of go miles to the Jamaican mountains. Here a 500-mile stretch of 

 islandless ocean confronts them, and scarcely a third of their number leave the forest-clad 

 hills for the unseen beyond. Chief among these is the Bobolink. With the Bobolink is an 

 incongruous company of traveling companions — a Vireo, a Kingbird, and a Nighthawk 

 that summer in Florida; the Chuck-will's-widow of the Gulf States; the two New England 

 Cuckoos; the Gray-cheeked Thrush from Quebec; the Bank Swallow from Labrador; and 

 the Black-poll Warbler from far-ofl Alaska. 



The main-traveled highway is that which stretches from northwestern Florida across 

 the Gulf, continuing the southwesterly direction which most of the birds of the Atlantic 

 coast follow in journeying to Florida. A larger or smaller percentage of nearly all the species 

 bound for South America take this roundabout course, quite regardless of the several-hun- 

 dred-mile flight over the Gulf of Mexico. 



The birds east of the Allegheny Mountains move southwest in the fall, approximately 

 parallel with the seacoast, and apparently keep this same direction across the Gulf to eastern 

 Mexico. The birds of the central Mississippi Valley go southward to and over the Gulf. 

 The birds between the Missouri and the edge of the plains and those of Canada east of the 

 Rocky Mountains move southeastward and south until they join the others in their passage 

 of the Gulf. In other words, the great majority of North American birds bound for a winter's 

 sojourn in Central or South America elect a short cut across the Gulf of Mexico in preference 

 to a longer land journey by way of Florida or Texas. In fact, millions of birds cross the Gulf 

 at its widest part, which necessitates a single flight of 500 to 700 miles. It might seem more 

 natural for the birds to make a leisurely trip along the Florida coast, take a short flight to 

 Cuba, and thence a still shorter one of less than 100 miles to Yucatan — a route only a little 

 longer and involving much less exposure. Indeed, the earlier naturalists, finding the same 

 species both in Florida and in Yucatan, took this probable route for granted, and for years 

 it has been noted in ornithological literature as one of the principal migration highways of 

 North American birds. As a fact, it is almost deserted except for a few Swallows, some shore 

 birds, and an occasional land bird storm driven from its accustomed course, while over the 



