18 THE O. & O. SEMI-ANNUAL. 
fifteen. But this no doubt varies in different localities, according 
to the nature of the soil. 
Writers of twenty years ago gave the number of eggs of this 
owl as four, while later authors say from four to ten. I think 
four seldom, if ever, constitutes a full set. Where incubation had 
commenced I have never found less than seven, while eight, nine 
and ten are more commonly found. I once found a set of eleven 
eggs, and again eleven young birds a few days old. They were 
covered with white down and were rather pretty. Last April I 
found my first set of twelve eggs and naturally felt very much 
elated over it. I knew that they were badly incubated but thought 
I would save them, no matter how much time it took. I had no 
time to attend to them until the second evening, and when I went 
to unpack them, I found that six of the young birds were nearly 
out of the shell, while the others were ‘‘getting there” as rapidly 
as possible. So I lost the largest set that I ever found, and very 
likely may neyer find another with so many eggs. 
The eggs of the Burrowing Owl are nearly round, of a pure, 
glossy white. The range of measurements are 1.16x.98 to 
1.35XI.10, averaging for a large lot 1.25x1.03. Fresh eggs may 
be found from middle of March to 15th of May, and perhaps 
later, but have never looked for them after that date. 
On April 24th and 25th, 1889, near Riverside, California, I 
dug out twenty-five or thirty nests of this owl. About one-third 
of these contained young of all sizes up to half-grown, one-third 
were full sets in all stages of incubation, while the balance were 
fresh, and ranging in numbers from three to ten. 
