Page:Condor15(1).djvu/48

48 THE CONDOR Vol. XV tus of food as they do in a wild state. Hence the fact that.a given animal is indiffurent 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, ?-t 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 conditi'ons, 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 ?eature of it is the series of bibliog? raphies occurring at intervals under the proper sub-headings.--JuNIUS HE?)ERSON. CONTRIBUTIONS TO AVIAN PALAEO NTOLOGY FROM THE PACIFIC COAST oF 'NORTH AMERICA. By LOYE HO?,MES Mn,?,ER (Univ. Calif. Publ. Geol., vol. 7, no. 5, Ociober 12, 1912, pp. 61- 115). The preseni 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 sel?arate papers relating to this field of ornithology. By far the most i.mportant of these are obviously those of MilleP 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 pr,esent 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 HAMMOrn), 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 nvestigation concerning the food of certain birds" by John Hammond. This paper gives some of the results of an in- vestigation instituted by Professor Wood 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