342 Distribution of Land Birds. [ZOE 
the small migratory birds; but if birds can reach the nearer islands 
they would have no difficulty in passing on to the more distant ones. 
In regard to the two varieties of the song sparrow and of the orange- 
crowned warbler, recently described by Mr. Townsend from the 
islands, it is too soon to pronounce upon their validity, although we 
should hardly expect to find recognizable races of thése forms,which 
it would seem are as well capable of flying from the mainland as is 
the golden-crowned sparrow. Still more remarkable does it seem 
that the race of the song sparrow found upon San Clemente Island 
(Melospiza fasciata clemente ) should be the same as that upon 
Santa Rosa, which is very near the opposite extremity of the group, 
while on Santa Barbara, midway between the two, another race — 
M. fasciata graminea — should occur. Should more ample material 
confirm these races, it will only show that in these cases, as with the 
next to be considered, the isolation has been sufficient to produce 
slightly different varieties. It will be noticed that these new races 
of Mr. Townsend’s are resident birds, which would account for their 
distinctive features, perhaps. 
In 1886 Mr. H. W. Henshaw described, in the Auk, a new species 
of jay from Santa Cruz Island (Aphelocoma insularis). In Mr. 
Henshaw’s own words—' the essential differences of the island bird 
from californica are its larger size, deeper colors (especially of the 
brown on back), and the blue under tail-coverts instead of white.” 
In accounting for the origin of this insular form he says: “ Individ- 
tals doubtless reached the island from the mainland, and being non- 
migratory their continued residence under new conditions has ef- 
fected very considerable changes of size and coloration.’’ This 
theory would seem to indicate that there was a time when the islands 
were destitute of an avifaun 
of the mainland and were gs 
glacial epoch, Woodhouse’ s, the Cali 
