6 PACIFIC COAST AVIFAUNA No. 10 



standard it is usually in cases where the author's personal experience leads him to 

 a different view; but there are one or two instances (such as with the group of 

 Tnncos) where the conclusions of some specialist, at variance with the Check-List, 

 arc so closely in accord with observations of the author's (in themselves perhaps 

 insufficient to warrant outspoken disagreement), that this worker's treatment of 

 the group is accepted in its entirety. 



The expedition conducted by the California AJuseum of Vertebrate Zoology 

 down the Colorado River from Needles to Yuma in the early spring of 1910, 

 furnished much valuable information in regard to the manner of occurrence of 

 many species of birds. An apparent inconsistency may be noticed in the citations 

 of certain of these records, inasmuch as some of them pertaining to occurrences 

 on the California side of the river have been quoted. Where this is done, however, 

 it is in the case of species which are known to occur in Arizona, but where there 

 is lack of data defining their status in this valley. In such a case, the record, 

 though strictly speaking not pertaining to Arizona, has a very definite value in 

 defining the status of an Arizona bird, and its use seems to be justified. 



The appended bibliography contains the titles of such publications as have 

 been consulted by the author in connection with the present contribution, the 

 criterion for the admission of a title being that the work relate definitely to the 

 ornithology of Arizona. Books of a general nature are not included unless they 

 contain some definite, first-hand information on the subject, something not pre- 

 viously published. It is hardly to be hoped, of course, that nothing has been over- 

 looked, and it is to be expected that additional titles relevant to the subject are 

 still to be found, but it seems unlikely that any such will be of a nature to serious- 

 ly modify many of the statements made in the following pages. 



The author's personal field work in the state has been ahiiost altogether in 

 the region lying between the Gila River and the Mexican boundary line. Trips 

 of varying lengths, during four different years and covering every month except 

 December and January, included parts of this region in great detail, and larger 

 portions in a more superficial manner. Of the three hundred and sixty-two spe- 

 cies and sub-species here credited to the state, two hundred and twenty-seven 

 were personally observed. In most cases specimens were collected. 



The accompanying map showing life zones of the state is presented with full 

 realization that it is probably open to criticir-m in many particulars, and will cor- 

 respondingly doubtless require revision in many of the details. At the same time 

 it is believed that it will be of sufficient aid in illustration of the distribution of 

 many species, and in showing the salient zonal peculiarities of the state, to fully 

 justify its publication, even in its admittedly tentative form. This map is com- 

 piled from various sources. The northeastern corner is copied from Merriam's 

 (1890) zone map of the San Francisco Mountain region; the zones of much of 

 the central portion of the state are computed from descriptions of localities in 

 publications of Coues (t866), Henshaw (1875), Scott (1886), Mearps (1890), 

 and others. Maps showing the distribution in Arizona of certain conspicuous 

 forest trees useful as zone indicators, loaned to the author by the District For- 

 ester's office, Albuquerque, New Mexico, were also used, and found of great as- 

 sistance. Much of the region south of the Gila River has been mapped from 

 persona] observations of the author. 



