Sep., 1901 I 
THE CONDOR 
129 
Nesting Habits of the Desert Sparrow Hawk Near Santa Monica, Cal. 
BY H. G. RISING, LOS ANGELES, CAL. 
I N this locality the sycamore trees 
found in the mouths of the canyons 
leading back into the foothills have 
always been favorite nesting places for 
the Desert Sparrow Hawk (Falco spar- 
verms deserticolusP) These trees are 
many of them very large, and the nu- 
merous cavities and woodpeckers’ ex- 
cavations furnish ideal nesting sites for 
these birds. Although there are a good 
many oak trees among the sycamores 
the Sparrow Hawks do not nest in 
them, and during five years collecting 
in this locality I have not found a sin- 
gle set of their eggs in an oak tree. 
There is one fact in regard to the 
nesting of these birds which I have 
never found any one able to explain. 
This is, why the birds never have to 
abandon a set of eggs on account of 
water during wet seasons. I have so 
often had the bird refuse to leave the 
nest that I always climb to it whether 
the bird is flushed or not. I have many 
times found a nest filled with water, 
and I always feel in the water for eggs 
but have never found any. These 
rains often occur right in the height of 
the nesting season, sometimes filling 
nests from which I had already taken 
one set of eggs. It seems strange that 
the birds do. not get caught in some of 
the leaky nests once in a while, but 
this does not seem to be the case. 
The nesting season here varies 
greatly, beginning as early as the 15th 
of March in some years and in others 
not until the middle of April. The 
duration seems to depend to a great ex- 
tent upon how many times the birds 
are robbed, as thej'^ will lay several sets 
if they are not allowed to hatch the 
eggs. 
This spring I started out with the 
intention of taking a series of Sparrow 
Hawks’ eggs for Mr. G. Frean Morconi 
of Los Angeles. As usual I did all of 
my collecting near Santa Monica, with 
the single exception of one trip up the 
beach to a canyon near Point Dumas, 
where I secured five sets of eggs. The 
remaining twenty-eight sets of this 
series all came from the same locality in 
which I have done most of my collect- 
ing, Santa Monica and vicinity. 
In making this series I used especial 
care with reference to keeping the eggs 
from each nest separate from those 
taken from other nests, so that the sev- 
eral sets taken from one nest during the 
season would constitute a series of 
itself. My intention was to watch the 
nests closely and to .take each set laid 
as soon as it was complete, in order to 
find out how long the birds would keep 
on laying; but I was unfortunately 
obliged to stop collecting the last of 
May and so could not complete the ex- 
periment. I took second and third sets 
from nests in several instances and in 
one case even got the fourth set. The 
intervals between the completion of the 
sets ranged from 20 to 26 days, with the 
exception of two, one of which was 29 
days while the other was 40 days. 
The following is a short record of a 
few of the nests from which I took sets 
this season. For the sake of conven- 
ience I refer to them as Nest No i. No 
2, etc. 
Nest No. I is a woodpecker’s exca- 
vation in the dead stump of a sycamore 
tree, and is about 15 feet above the 
ground. The mouth of the opening 
has been broken open until the hole is 
about five inches wide by fourteen 
deep. I took the first set of five fresh 
eggs from this nest on March 24, the 
parent bird watching proceedings from 
a neighboring tree. The second set of 
five eggs, also perfectly fresh, was 
taken April 18, the bird being flushed 
before the nest was reached. The 
third set, consisting of four slightly in- 
cubated eggs, was taken May 9. A 
fourth set ot two eggs, also slightly in- 
cubated, was taken on the 29th of May. 
On these last two occasions the birds 
