9 2 
THE CONDOR 
| Vo i,. VIII 
one valley in a distance of six miles we found twenty-two hawks’ nests. Seven of 
these nests were occupied by red-tails, three by horned owls and one by a red- 
bellied hawk. Each pair of red -tails usually had two and sometimes three nests, 
for they seem to occupy different nests from year to year. Two nests were often 
found built close together and in one instance there were three nests in one clump 
of trees. 
These twenty-two nests were all located in sycamores which often stood at a 
bend in the creek or near the edge of the grove. By actual measurement we 
found that the average height from the ground of twenty-two nests was fifty-five 
feet. The extremes were seventy-five and forty-three feet. We estimated that 
there was a pair of hawks to every one-half square mile of territory. What be- 
comes of the offspring in this densely populated district is a problem that I have 
been unable to solve. But some of them evidently stay near their birthplace as we 
found that out of seven pairs, two pairs had moved in since last year. 
Each pair of hawks had its own squirrel pasture and the birds resented the 
trespassing of other hawks on their domain. The remains of gophers, ground 
squirrels, meadow mice, young cottontails and two species of snakes, the striped 
racer and gopher snake, were found in red-tails’ nests, but ground squirrels seemed 
to be their principal diet. I found as many species of small mammals in hawks’ 
and owls’ nests in two days as 1 did by trapping for a week. 
In 1905, between March 25 and April 1, we found thirteen pairs of red-tails 
nesting, but none of the eggs had hatched up to that time. One set of four, four 
sets of three, seven sets of two and one incomplete set of one were found, making a 
total of thirteen sets and thirty-one eggs. This year fourteen pairs of red-tails 
were located. 
On March 28 a nest was found that contained two eggs and one young bird. 
One of these eggs was moving about in the nest and when I turned it over I 
found that the young bird had its bill out and was wriggling and squeaking feebly. 
The hole in the egg attracted my attention as it had apparently been made from 
the outside instead of the shell being pushed out from within; for the pieces of 
shell about the edges of the hole all pointed inward instead of out, and the hole 
was not big enough for the young bird to stick its head out and then draw it back 
thus drawing the pieces of shell with it. I have noticed this same thing before 
and believe that sometimes the old bird pecks the hole, thus aiding the youngster 
to escape at the proper time. 
Another nest was found just ready for eggs on March 30. The other twelve 
nests contained the following: two sets of four, four sets of three and six sets of 
two. In 1905 twelve sets made a total of twenty-nine eggs. In 1906 
twelve sets made a total of thirty-two eggs. Thus it will be seen that there 
were ten per cent more eggs laid this year than there were last year. In 
a number of cases the bird that laid two eggs last year laid three this year 
and the birds that laid the sets of four this year laid only three eggs last year. 
It is interesting to note that the eggs as well as the sets were larger this year 
than last. The average measurements of twenty-six eggs last year were 2.36 x 
1.78 inches, while this year the average of thirty eggs was 2.39 x 1.84 inches. The 
average number of eggs in a set was 2.38 last year and this year it was 2.66. The 
average measurements of fifty-seven eggs was 2.38x1.81 inches and an average 
based on twenty-five sets showed that there were 2.52 eggs in each set. The 
largest set of eggs found measured 2.45x2.00, 2.56x1.95, 2.46x1.99 inches, while 
the smallest eggs measured 2.23 x 1.73, 2.30 x 1.78 inches. The smallest number 
of eggs in a complete set was two and the largest four. 
