Mar., 1918 



EDITORIAL NOTES AND NEWS 



95 



died at Santa Barbara on January 23, 191S, 

 after having reached the sixty-third year of 

 his age. Mr. Hazard was well known as 

 an enthusiastic oologist and as a man ever 

 ready to advance the interests of others in 

 this field. 



PUBLICATIONS REVIEWED 



A Study j of the | Incubation Periods j 

 of Birds | — (What determines their j 



LENGTHS? | — | By | W. H. Bergtold. M. D., 

 M. Sc. { Member of the American Ornitholo- 

 gists' Union j The Kendrick-Bellamy Co. j 

 Denver, Colorado j 1917 (our copy received 

 June 20, 1917) ; 8vo, pp. 1-109. 



The above title brings to the attention of 

 bird observers a field of observation in 

 which, as the author well states, there is "a 

 lamentable dearth of information". Never- 

 theless the data finally gathered and here 

 presented is really of astonishing quantity 

 (though not always of acceptable degree of 

 accuracy), and has proven sufficient for the 

 establishment tentatively of several inter- 

 esting conclusions. Among these are that 

 length of incubation is not directly or close- 

 ly correlated with either size of the bird, or 

 size of the egg, or size of the yolk, or de- 

 gree of precocity of the young, or age of the 

 female, or longevity of the species. There 

 is, however, a "true" incubation period (se- 

 cured by allowing for all factors which serve 

 to prolong the process abnormally) which is 

 constant and characteristic of each species, 

 and this is directly correlated with the body 

 temperature — the higher the temperature 

 the shorter the incubation period. Now, 

 such data as are available seem to show that 

 the lower or more generalized a bird in the 

 phylogenetic scale, the lower its tempera- 

 ture; so that, again, the incubation period 

 allies itself in degree of abbreviation direct- 

 ly with degree of phylogenetic advancement 

 of the species concerned. 



The above brief epitome is inadequate to 

 give a fair idea of Bergtold's discussion of 

 the many phases of the subject involved, 

 and we can only recommend that interested 

 readers take the first opportunity to fully 

 apprise themselves of the contents of the 

 book. 



Referring again to lack of information, the 

 following are the facts called for by Berg- 

 told, if further enquiries along this and re- 

 lated lines are to be pursued fruitfully: Ex- 

 act length of incubation period of birds and 

 reptiles; exact length of incubation of birds 

 in polar and tropical regions; the period of 

 viability of birds' eggs; the weights of birds, 

 preferably of the breeding female; the 



weights of birds' eggs; the effects of super- 

 heating on birds' and reptiles' eggs; the op- 

 timum incubation temperatures of birds' 

 and reptiles' eggs; bird temperatures; tem- 

 peratures under the incubating bird; reptile 

 temperatures; minutiae of bird physiology. 



Egg-collectors, skin-collectors, and na- 

 ture students of the opera-glass contingent 

 are here on common ground in that all are 

 in positions to contribute importantly to the 

 stock of facts needed. — J. Grinnell. 



The Distribution of Bird-life in Colom- 

 bia; A CONTRIBUTION TO A BIOLOGICAL SURVEY 



of South America. By Frank M. Chap- 

 man. Bulletin of the American Museum of 

 Natural History, vol. xxxvi, 1917, pp. i-x, 1- 

 729, 41 plates (some colored), 21 text figs. 



The ultimate object of the several years of 

 zoological exploration which the American 

 Museum of Natural History has been prose- 

 cuting in South America is, we are told, the 

 discovery of the geographic origin of South 

 American life. As a step toward the at- 

 tainment of this end the publication here re- 

 viewed is devoted to a careful study of the 

 birds of a relatively restricted part of the 

 continent, in their racial variation and geo- 

 graphic distribution — of the "life zones" and 

 "faunal areas", and the species and subspe- 

 cies inhabiting them. As explanatory of the 

 peculiar interest attached to the study of 

 the birds of Colombia, the chapter devoted 

 to "a review of Colombian ornithology" is 

 briefly descriptive of the "Bogota" collec- 

 tions, productive of so many new species of 

 birds in years gone by, pointing out the 

 value of these collections in the early study 

 of the birds of this region and their abso- 

 lute uselessness in a present day investiga- 

 tion relative to the distribution of species. 

 Californian ornithologists will be especially 

 able to appreciate the points here made, as 

 to the necessity for absolute accuracy in the 

 labelling of specimens. 



The life zones recognized by the author 

 in Colombia are four in number, being, in 

 ascending order, Tropical, Subtropical, Tem- 

 perate, and Paramo, the last mentioned be- 

 ing a term "locally applied to any treeless 

 region lying above 10,000 feet". Some im- 

 portant conclusions as regards the existing 

 fauna of the region are as follows: That the 

 birds of every zone above the tropics have 

 been derived from a lower level; that the 

 Temperate zone of the Colombian Andes 

 reaches sea level farther south in South Am- 

 erica and that its life is derived in part by 

 zonal, in part by latitudinal extension and is 



