VOL. Ir. | Nesting Time of Birds. 169 
We come next to the larger birds of prey. Incubation appar- 
ently commences with tolerable regularity among them during the 
latter half of March. By far the commonest of these birds is the 
western red-tailed hawk ( Buteo borealis calurus) which nests either 
in rain-washed holes or scoops in the faces of rocky cliffs or in the 
tops of live oak, or occasionally in a pine. The earliest record of 
fresh. eggs is March 18, 1876, from which time on they may be 
found until nearly the middle of the following month. A second 
set may sometimes be laid in May. About the same time that the ° 
red-tail begins to breed the western great-horned owl ( Budo virgin- 
tanus subarcticus) commences nidification. Mr. Bryant has found 
their eggs among the rocks in the retired cafions back of Berkeley in 
years past, and they still breed in this region, though probably in 
diminished numbers. Only one brood is raised; the latest date on 
which eggs are recorded being April 10, 1880. The breeding range 
of the prairie falcon (Falco mexicanus) is now very much more re- 
stricted than it was in 1877, when Mr. Bryant collected its eggs near 
Berkeley. At present it apparently breeds in no locality about 
here except in the rocks of Mt. Diablo, where we observed the 
birds feeding their young as late as the last of July this year. As 
the first eggs are laid as early as March 22, they apparently have 
two broods a year. There are but two other raptorial birds which 
breed about here in March, the turkey buzzard ( Cathartes aura) 
and the American barn owl (Stix pratincola). Both species nest 
during the latter part of this month and the beginning of the suc- 
ceeding one, while neither, so far as the data at hand shows, raise 
but one brood a year. 
We have now noted the species breeding in March in the region 
in question and traced their periods of nesting through the remain- 
der of the season. Let us now take a brief survey of the field at 
the opening of April. Besides the species above mentioned, all of 
which are by this time well under way with their domestic duties’ 
two new birds have now begun to breed, the California shrike 
(Lanius ludovicianus gambeli) and the California jay (Aphelocoma 
californica). With the exception of one set of four eggs taken by 
Mr. Bryant on March 26, 1881, we have no record of the breeding 
of the latter species before April, while the shrike seldom lays its 
first egg much before the beginning of this month. A little later 
the smaller raptorial birds commence breeding—first the western 
