528 The American Naturalist. [June, 
THE ORIGIN OF THE AVIFAUNA OF THE 
BAHAMAS. 
BY FRANK M. CHAPMAN. 
S° far as the relationships of the islands themselves are con- 
cerned the Bahaman group offers from the zoological stand- 
point an apparently simple case. Asa coral formation arising 
from the Bahaman banks we may regard them as oceanic and of 
independent origin. In an analysis of their fauna, therefore, we 
are not confronted by the perplexing problems which beset us in 
studying the larger West Indian Islands, where a probable con- 
nection with the mainland greatly enlarges the scope of our 
inquiry, and renders more involved the questions to be determined. 
Here, however, we have an area which has not been populated by 
a past connection with contiguous regions, but owes its life to the 
more or less fortuitous occurrence of the ancestors of the species 
which now inhabit it. Primarily through the resulting isolation 
the original forms have in many instances become evolved into 
what we term new species, whose range is restricted to one OF 
more of the islands in question. The Bahamas possess no indig- 
enous terrestrial Mammalia, and thus conform to the law which 
generally obtains among oceanic islands. The two or three 
species of Mus which are found there have evidently been intro- 
duced through artificial means. 
Birds, however, possessing in their power of flight a most effec- 
tive means for extended wanderings, have found the intervening 
waters no bar to their occupation of the Bahamas. The islands — 
furnish them with resting places in their migrations, with homes — 
during the rigors of a northern winter, with breeding grounds 
during the summer, or with a permanent habitat, beyond which © 
they are unknown. > 
We may imagine these islands as at first barren coral reefs and 
sand-bars, tenanted alone by gulls, terns, and other pelagic spē- 
cies, as indeed some of the islands are now. But, devoid ofa 
vegetation which, through its fruit or support of insect life, would 
