Pennock, on Burrowing Owl 
27 
made short flights. Twice she alighted on a low, broken pine 
sapling about four feet high and this I had seen her use but 
once previously — on April first.” Having constantly found both 
birds at their respective entrances where the nests contained 
eggs, whether they were fresh or advanced in incubation to- 
gether with finding the nest cavities so near the surface of 
the ground at a time when the ground was extremely dry and 
the thermometer above 80° in the shade — 100° or more in the 
open where the nests were located, it might appear probable 
that the heat of the ground was sufficient during a considerable 
part of the day to continue incubation without the aid of the 
bird. No other explanation seems reasonable to account for the 
constant appearance of both birds outside the burrows. 
So far as I am aware all authors have held or inferred that 
the plumage of the sexes is alike. Some speak of the individual 
variations which are not constant. The birds as I found them 
were notably different in shade of color and this could frequently 
be detected as they flew. By placing the birds on their backs, a 
series of each sex opposite, the difference is marked and con- 
stant ; the cross-bars of the female being the darker, those of the 
male almost fading away towards the tail. With the female 
the cross-bars ranged from Bister on upper breast to Dresden 
Brown on lower belly while corresponding bands on the male 
ranged from Front’s brown to tawny olive. The backs of the two 
sexes show slight differences and are not constant so far as I 
could determine. In several cases faint cross-bars were detected 
on the under tail coverts or spots that may be grouped to form 
a bar. 
Measurements of the birds varied considerably especially as to 
length, but this could be accounted for at least in part by the 
wearing of the tail, the tip of which was frequently much frayed, 
doubtless due to wear in the burrows. 
MEASUREMENTS 
L. 
W. 
T. 
Trs. 
<y Average 
9.08 
6.61 
3.38 
1.94 
9 Average 
9.09 
6.6 
3.31 
1.91 
Extremes 
^8:50 
6.50 
3.25 
1.88 
/ 9 : 50 
6.88 
3.50 
2.12 
9 Extremes 
18.63 
6.43 
3.06 
1.88 
|9.50 
6.88 
3.50 
2.00 
All speciments were adults, taken between February 19 and April 16. 
The eggs were of course pure white when blown. The usual 
