FRIENDS OF OUR FORESTS tt 
many and prominent. As most birds, es- 
pecially the warblers, choose starlight and 
moonlight nights for their trips, perhaps 
they are similarly guided by night, and 
natural landmarks, as mountains, rivers, 
and the coastline may point out much, if 
not all, of their way. 
However plausible this explanation may 
sound in the case of birds migrating over 
land, it utterly fails when applied to mi- 
grants whose journeys north and south 
necessitate flight over long stretches of 
ocean, in some instances at least 2,000 
miles, quite out of sight of land and of 
all landmarks (see pages 180-195). 
In seeking an explanation of the mys- 
tery of birds’ ability to find their way 
under such circumstances, many are in- 
clined to reject the one-time sufficient 
answer, “instinct,” in favor of the more 
recent theory, the possession by birds of 
another faculty, the so-called “sense of 
direction.” This added sense enables 
birds to return to a known locality with 
no other aid than an ever-present knowl- 
edge of the right direction. 
But, in the case of our wood warblers, 
there is little need of appealing to another 
sense to guide them in migration, or, in- 
deed, to anything out of the ordinary save 
excellent memory and good eyesight. The 
five-hundred-mile flight toward the trop- 
ics across the Gulf of Mexico is made by 
preference, and however it originated as 
a fly line, had it proved to be extra haz- 
ardous, it might have been abandoned at 
any time in favor of the apparently safer 
West Indian route. 
But, after all, the Gulf trip involves few 
~\hazards other than those connected with 
storms, since the flight across the water, 
even at a slow rate, would necessitate a 
journey of less than 24 hours, and this, 
no doubt, is quite within the capacity of 
even the smallest and weakest of the 
family. Moreover, the South American 
Continent is too big a mark to be easily 
missed, and an error of a few hundred 
miles north or south would make little 
difference in the safety of the birds. 
WHY WARBLERS MIGRATE 
It may be set down as an axiom that 
all birds which travel south in fall do so 
because they must migrate or freeze or 
starve. Why some of them leave early, 
when food in their summer home is seem- 
ingly so abundant, is indeed a puzzle. 
Once the nestlings are on the wing and 
ready for the journey, off they go, old 
and young. 
Nevertheless, by an apparently prema- 
ture start they only anticipate by a few 
weeks the time of scarcity when they 
must go, and perhaps the lesson of bitter 
experience in the history of the several 
species has taught them to go when all 
the conditions are favorable. It is true 
that every winter a few birds, often a 
few individuals of a given species, winter 
far north of the customary winter home. 
Some of these are evidently stragglers or 
wanderers which, for some unexplained 
reason, failed to accompany the rest of 
their kind on the southward migration. 
They in no wise affect the general state- 
ment, being exceptional in every way. 
A few of our warblers in Florida and 
on other parts of our southern coast do 
not migrate; but the almost universal rule 
in the family is to abandon the summer 
home when the care of the young ceases 
and to go far southward ere they stop for 
the winter. Indeed, the males of many 
species do not trouble themselves much 
with the care of the nestlings, but prepare 
to migrate before the young are well on 
the wing. 
A still more flagrant case is that of the 
hummingbirds. The male deserts the 
female when she is still on her eggs, 
shifting the responsibility of caring for 
the family entirely on her devoted head, 
while he disports himself among the 
flowers, leaving for the south long before 
his exemplary mate and the young are 
ready. 
Some of our species, however, while 
migrating southward, are satisfied to re- 
main all winter within our boundaries. 
Thus the pine and palm warblers winter 
in the Gulf States, while a greater or less 
number of individuals, representing sev- 
eral species, winter in southern Florida. 
The great majority, however, winter 
south of the United States, in Central 
and South America. 
Thus Professor Cooke tells us: “The 
prairie, black-throated blue, Swainson’s, 
Bachman’s, Cape May, and Kirtland’s 
