Vlll 
INTRODUCTION. 
Natural History Series, and was devoted to a description of the Land Birds occur- 
ring west of the Bocky Mountains and north of Mexico, having been selected 
as the volume most suitable to succeed those of Geology and Palaeontology 
already published, partly because it was thought that the subject would prove 
popularly attractive, and partly because circumstances favored its being more 
rapidly completed than the other volumes of the Natural History Series possibly 
could be. 
For the volume of Land Birds published in 1870 by the California Survey, 
the biographical portion was chiefly drawn from the notes of Dr. J. G. Cooper, 
Zoologist of the Survey ; and by mutual consent these notes were placed in the 
hands of Professor Baird, at that time in charge of the Natural History Depart- 
ment of the Smithsonian Institution, in order that they might be worked up 
at the place where a more copious supply of materials and greater facilities for 
such an undertaking existed than at any other scientific centre in this country. 
The result was the publication, in 1870, of a volume entitled: “Ornithol- 
ogy. Volume I. The Land Birds.” It was illustrated by nearly eight hundred 
woodcuts, each species (except in the case of the Rapt ores) being represented 
by a head of life size, introduced with the text, and intended to be colored by 
hand, and each genus by a full-length figure, together with numerous diagrams 
giving the details of wings, claws, and such other parts as are of special value 
in generic determination. 
During the preparation of this ornithological volume of the California series 
of Beports, it was agreed between the State Geologist and Professor Baird that 
the illustrations of that volume should be used by him in a work of larger scope, 
including the Land Birds of all North America; and this plan was carried out, 
the result being the well-known work, in three volumes, entitled “ A History of 
North American Birds : Land Birds,” by Messrs. Baird, Brewer, and Bidgway. 
This work — completed in 1875 — followed closely the California volume in its 
general style, appearance, and manner of illustration ; the principal exception to 
this being that the heads were placed together at the end of each volume, and 
printed by the cliromolithographic process, instead of being colored by hand. For 
these volumes between seven and eight hundred illustrations were furnished by 
the California Survey without charge — Professor Baird having promised, in return 
for this favor, that the portion of the Ornithology remaining to be completed 
and published as a part of the California Beport should include all the Water 
Birds of the continent north of Mexico. The propriety of this stipulation must 
be evident to all, since it was clear that, after the appearance of the work of 
Messrs. Baird, Brewer, and Bidgway, there would be only the most limited 
demand for the much less comprehensive one previously issued by the California 
Survey. 
