182 
MAP SHOWING THE PRINCIPAL ROUTES 
USED BY BIRDS IN THEIR MIGRATIONS 
i¢t "BETWEEN NORTH AND 
J SOUTH AMERICA 
The different courses taken by the 
birds to get around or over this inter- 
vening inhospitable region are almost as 
numerous as the bird families that trav- 
erse them, and only some of the more 
important ones are shown on the accom- 
panying map. The routes are numbered 
from the east westward. 
The middle route, No. 4, is by far the 
most important. In general it may be 
said to extend from northwestern Flor- 
ida and western Louisiana across the 
Gulf of Mexico to the southern coast of 
the Gulf (Yucatan to Vera Cruz), and 
thence by land through Central America 
to South America. Probably more indi- 
viduals follow this route than all the 
other routes combined. 
The birds east of the Alleghany Moun- 
tains move southwest in the fall approxi- 
mately parallel with the seacoast, and 
most keep this same direction across the 
Gulf to eastern Mexico. The birds of 
the central Mississippi Valley go south- 
ward to and over the Gulf. The birds 
between the Missouri River and the edge 
of the plains, and those of Canada east 
of the Rocky Mountains, move south- 
eastward 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 win- 
ter’s sojourn in Central or South Amer- 
ica elect a short cut across the Gulf of 
OUR GREATEST TRAVELERS 
Mexico in preference to a longer land 
journey by way of Florida or Texas. In 
fact, millions of them cross the Gulf at 
its widest part, which necessitates a single 
flight of 500 to 700 miles. 
The peninsula of Florida extends far 
to the south, and the great island of 
Cuba forms a convenient stepping-stone 
between its coast-line and Yucatan. A 
bird taking this highway would avoid 
any long single flight; yet, with the ex- 
ception of a few day-migrating swallows, 
no bird is known to follow this route. 
A probable explanation is that southern 
Florida has vastly less bird food per 
square mile than the country to the 
northward, and the birds prefer a single 
long flight with abundant rations to a 
series of shorter flights on Scantier fare. 
Migration route No. 3, which is by 
way of Cuba and Jamaica, offers a much 
shorter journey to South America, but it 
is traversed by only a few species... It is 
popular as far as Cuba with some 60 spe- 
cies, of whom great numbers. spend. the 
winter on the island; about 30 of these 
species have a small contingent who pass 
on to make Jamaica their winter resort; 
but scarcely more than 10 species try the 
final long flight across the Caribbean Sea 
to South America. Among these are one 
species each of six widely differing fami- 
lies—the bank swallow, gray kingbird, 
Florida nighthawk, Alice thrush, black- 
poll warbler, and bobolink. The other 
members of those families employ en- 
tirely different migration routes. 
It is not possible to ascertain whether 
these travelers on the so-called “bobolink 
route” represent adventurous species that 
are seeking to improve on the round- 
about course through Mexico, or old 
fogies who hold to the way of their fore- 
fathers long after their brethren have 
proven to their own satisfaction the su- 
perior advantages of the more western 
route. 
The next route to the eastward, No. 2, 
traverses the chain of islands that ex- 
tends from Florida to South America. 
This, too, is considerably shorter than 
the Florida-Yucatan route, and land can 
always be kept in sight; yet this line also 
is discredited. A few individuals of 
about 25 species follow it as far as Porto 
