48 
THE CONDOR 
Vol. XV 
lus of food as they do in a wild state. Hence 
the fact that a given animal is indifferent to, 
or even rejects, a certain species of insect 
when in captivity, by no means indicates that 
it would be indifferent to or reject the same 
species under natural conditions. Indeed, it 
has been definitely shown that many “disre- 
garded” and “rejected” species are actually 
taken by wild animals of the same species as 
those experimented upon. 
The whole doctrine of warning colors and 
mimicry is built upon the presumption that 
the species mimicked is . disagreeable or dan- 
gerous, and hence under the law of natural 
selection the mimicking species has come to 
assume the same colors as the one mimicked ; 
this presumption is in many cases unsup- 
ported by any evidence, and in many other 
cases is quite contrary to the known facts. 
Dr. McAtee’s conclusion is that since accep- 
tance or rejection of food in captivity bears 
no close relation to food preferences under 
natural conditions, the value of experiments 
upon captive animals to determine the effici- 
ency of warning colors and other protective 
adaptations in their insect food is very ques- 
tionable. It should be checked up with such 
definite knowledge of the natural food as is 
obtained by the examination of contents of 
stomachs or other portions of the alimentary 
canals. He clearly shows that many species 
which have been considered to be protected 
by noxious secretions or other adaptations 
are not really so protected, a conclusion sup- 
ported not only by the definite evidence pro- 
duced by Dr. McAtee, but also by the fact 
that if such species were not preyed upon by 
various enemies they would soon people the 
whole earth. Whether the reader finally 
agrees with Dr. McAtee or not, he will find 
in this timely paper much information and 
food for thought, and by having read it will 
be better prepared for intelligent considera- 
tion of the subject. By no means the least 
valuable feature of it is the series of bibliog- 
raphies occurring at intervals under the 
proper sub-headings. — Junius Henderson. 
Contributions to Avian Palaeontology 
FROM THE Pacific Coast of North America. 
By Loye Holmes Miller (Univ. Calif. Publ. 
GeoL, vol. 7, no. 5, October 12, 1912, pp. 61- 
115). 
The present paper is a detailed summary of 
our knowledge to date of the fossil birds of 
the Pacific coast. The accompanying bibliog- 
raphy shows that there have been published 
eleven separate papers relating to this field of 
ornithology. By far the most important of 
these are obviously those of Miller himself 
who has been fortunate in having full access 
to the rich material accumulated under the 
direction of Dr. J. C. Merriam in the depart- 
ment of palaeontology of the University of 
California. 
Of the eight localities on the Pacific slope, 
in which fossil birds have been found, six are 
in California. The most notable of these lo- 
calities, the now famous Rancho la Brea, near 
Los Angeles, has produced no less than for- 
ty-nine species of birds, with promise of fur- 
ther discoveries as excavations there are con- 
tinued in the future. 
Miller’s present contribution includes an ac- 
count of each of the fossil faunas, with lists 
of the species known from each. Past dis- 
tribution as thus shown in the regions con- 
cerned is compared with present day condi- 
tions. Various lines of evidence point to- 
wards a Pleistocene climate of higher tem- 
perature and greater humidity than now. 
The Pleistocene avifauna contained several 
types of birds not now found north of South 
America. There appears to have been a re- 
traction in the ranges of these types to the 
southward. There were many more species 
of eagles and vultures in California in Pleis- 
tocene times than now. 
Among causes of the extinction of rap- 
torial species Miller considers as of probable 
importance, the disappearance of forests and 
luxuriant meadow vegetation, and the great 
reduction in the population of herbivorous 
mammals. J. C. Merriam’s studies indicate 
the disappearance of many species of carniv- 
orous mammals at about, the same time with 
the raptorial birds now extinct. Dr. Miller 
believes the coincidence significant of de- 
pendence of the scavenging birds upon the 
beasts of prey, in that the former fed largely 
upon the discarded kills of the latter. — J. 
GrinnelL. 
An Investigation Concerning the Food of 
Certain Birds. By John Hammond, B. A. 
(Journal of Agricultural Science [Cam- 
bridge], June, 1912, 4, pp. 380-409). 
As a further contribution to a knowledge 
of the food of the birds of England has come 
a paper entitled “An investigation concerning 
the food of certain birds” by John Hammond. 
This paper gives some of the results of an in- 
vestigation instituted by Professor W ood and 
Mr. Warburton of the School of Agriculture, 
Cambridge, “to determine whether or not cer- 
tain birds were harmful to agriculture.” The 
method adopted in the investigation was “the 
examination of stomach contents, together 
with a collection of field notes concerning 
each bird.” 
In beginning the investigation the following 
points were taken into consideration : 
“(1) That the examination of the stomach 
contents ought to be continued throughout the 
