ACADEMY OF SCIENCES. 197 
near San Francisco, where I saw them in the middle of January, 1875. The 
occurrence of this species farther east than formerly, some even to the 
Atlantic coast, seems to show that the denudation of the greater part of the 
Appalachian forests, is producing the effect of making that country so much 
better suited to the habits of birds of the great western plains, that they are 
gradually moving eastward. This migration, commenced by the Cliff Swal- 
low in 1811, is now noticed in the Yellow-headed and Brewer’s Blackbirds, 
the Magpie, Arkansas Flycatcher, and several others more fond of the 
forests, most of which could not have been overlooked by the old observers. 
GuUIRACA C@RULEA—Blue Grosbeak—p. 230. In 1873, I saw the males of 
this species migrating north in small parties through Ventura Co. on April 
17th, so that they come earlier along the coast than at Ft. Mojave. On the 
same day the allied Cyanospiza was migrating, as usual, in flocks, together 
with Dendreca estiva. In 1875, the two latter reached Haywood, Alameda 
Co., April 20th; but the Grosbeak seeks a more inland route toward the north. 
The arrival of most spring birds is varied a week or two by the winds and 
weather, as a few warm days and south wind always bring them in large 
flocks, when the contrary conditions either delay them all, or make them 
arrive in scattered order. The prevalence of fogs for 20 miles inland during 
many nights of spring also changes the route of some or all the migrants. 
AGELEUS TRICOLOR—Red and White-shouldered Blackbird—p. 265. The 
eggs of this bird, instead of being like those of Brewer’s Blackbird, as I 
quoted from Dr. Heermann, are almost undistinguishable from those of the 
other Redwings. Dr. Brewer calls them deeper blue; but many found by me 
at Saticoy, Ventura Co., are rather pale green, with few dark brown blotches 
and lines near the large end. The nest differs more, being of straws, stems, 
and leaves, twisted around several upright stems of nettles, about four feet 
from the ground, and in the forks of the plants. They are about 7 inches 
high, 5 wide, inside 3 by 3, with a fine grass lining. Hundreds built in one 
netile thicket, around a marshy spot, but none in the cat-tails or rushes near 
by. The nettles were a protection from raccoons, etc. 
Corvus (AMERICANUS var.) CAURINUS—Western Crow—p. 285. Prof. Baird 
still insists on the specific distinctness of this form, as found from the Columbia 
River to Sitka, returning all Californian specimens to C. Americanus. The 
differences now first given by him are, ‘‘ tarsus shorter than the bill, 1st quill 
longer than 10th, gloss deeper,’’ besides the smaller size. But the plates in 
his former work, and the tables given with them, do not show such a constant 
difference in bill and tarsus as ‘‘ culmen, 1.95; tarsus, 1.70,’ nor do they show 
any marked disproportion in the wings or tarsi of the two ‘“‘ species.” The 
var. Floridanus is quite as peculiar in having larger bill and tarsus, but many 
intermediate specimens, some of which I myself collected at Ft. Dallas, 
Fla., connect it with Americanus. 
In the same way the California birds connect the var. caurinus with Ameri- 
canus. In his former work, Prof. Baird himself mentions the less graduated 
tail of Californian skins, and includes in caurinus several northern specimens 
of intermediate sizes. 
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