THE EFFECT OF CLIMATE UPON PACIFIC COAST 
- BIRDS. 
BY L. BELDING. 
It has been the custom of American ornithologists to refer to the 
birds of the damp forests on the coasts of Northern California, Ore- 
gon, Washington, and British Columbia as the ‘dark, northwest 
coast birds;’’ of the birds of the arid treeless areas east of the Cas- 
cade and Sierra Nevada Mountains, of the Mojave and Colorado 
deserts and Arizona, as the ‘‘bleached desert races;’’ of the resident 
‘peculiar forms of the Sacramento and San Joaquin valleys, as birds 
of the ‘‘dry, hot interior,” thus referring to localized forms, which 
migrate little, ifat all, and in the terms quoted, correctly conveying the 
idea that the environment or climate inhabited by these forms is the 
cause of their divergence from nearly related species and sub-spe- 
cies. A familiar axiom carrying the same idea is, ‘‘ Migration holds 
species fast, localization lets them slip,’’ the purport of which is that 
birds which migrate and are subject to many conditions are much 
less liable to change than those which do not migrate and are subject 
to few conditions. Whatever potency natural selection or sexual 
selection ay have in causing differentiation—and their operation 
in this-direction seems very obscure—here, where there is such vari- 
ety of climate, soil, and vegetation, consequent upon difference in 
altitude and humidity, proximity to the ocean and removal from it, we - 
may well consider climate as our most important factor in evolution. 
Turning from birds to man, we see in our country, descendants of 
people of various European nationalities who bear the impress of our 
climate and the distinctive characteristics of Americans. Even the 
pure-blooded Jew, whose occupations and modes of living vary but 
little, is similarly affected, and I have noticed that the English Jew 
resembles, more or less, the Englishman, the German Jew the Ger- 
man, and I think the Polish Jew is different from any of these. It 
is difficult to see how selection could have had much influence in 
modifying the Jew. 
The black man appears to be one of the ioral products of Africa, 
the copper-colored man of America, but I would not venture to pre- 
dict that the Caucasian and negro of America will in the dim future 
become copper colored, and that our vexatious race problem will in 
this way be solved, but I do venture to protest against giving the 
theory of selection undue prominence. 
