86 
Cooper on the California Pygmy Owl. 
NOTES ON THE BREEDING HABITS OF THE CALIFORNIA 
PYGMY OWL ( GLAUCIDIUM CAL1FORNICUM), WITH A 
DESCRIPTION OF ITS EGGS. 
BY WILLIAM A. COOPER. 
To Mr. George H. Ready, whose untiring exertions in the oological 
line have placed him among our most reliable collectors, I am under 
obligations for the material for this article. 
June 8, 1876, while collecting in the bed of the San Lorenzo 
River, two miles from Santa Cruz, Cal., he saw a male Pygmy Owl 
with a Brown Towhee in his claws alight oil one of the topmost 
branches of a dead, isolated poplar-tree standing on the bank of the 
river. Mr. Ready did not hear the bird call his mate, but in a mo- 
ment she came out, took the food brought to her, and returned to 
the nest, which was in a hole in the trunk of the tree, about seventy- 
five feet from the ground. 
An hour’s climb, which he pronounces the most difficult and 
dangerous he ever attempted (it being quite windy at the time), 
brought him to the nest, which was in a Woodpecker’s deserted 
burrow, about nine inches deep and two inches across the mouth. 
The female bird was incubating on tivo eggs, and would not leave 
the nest. After removing her and the eggs, together with the 
Towhee (the head and neck of which were gone), Mr. Ready exam-- 
ined the nest. The eggs rested on a bed of twigs and a few feathers 
forming a lining three inches deep ; in removing this he accidentally 
broke another, an unfertilized egg, situated in the middle and com- 
pletely covered by the twigs. The question arises, Was this nest 
made by the Owl ? Taking into consideration the facts that Owls 
usually build no nest ; that the twigs of which the nest was 
formed were identical with those used by Troglodytes parhnanni , 
and that this Wren builds in similar places, sometimes as high, and 
is a persistent builder ; that the feathers may have been placed 
there by the Wrens, or have accumulated from birds the Owls fed 
upon, - — it seems probable that the nest was really a Wren’s of which 
the Owls had taken possession. In regard to the addled egg, the 
Owls and Wrens may have contested for possession of the nest, and 
the egg been covered up by twigs brought by the latter ; or it may 
have been laid in a hollow formed by the twigs which the Owls 
