176 THE CONDOR Vol. XXIII 
on the nest he maintained a vigilant watch, frequently peering over the edge 
and closely scrutinizing the ground beneath. The female evidently oceupied 
the nest at night, as well as part of the day. The two young gnatecatchers 
were not allowed to loiter near the nest. 
On June 21 newly hatched young were found. The exact time during 
which they occupied the nest was not determined, but it was at least a day or 
(wo longer than in the previous case. This was not due to their remaining 
until a later stage of growth, but to an actual slower development. The nest 
a b 
Fig. 39. a, MALE BLACK-TAILED GNATCATCHER NEAR NEST, THE LATTER BEINGS 
SITUATED IN DENSE GROWTH AT LOWER LEFT; PHOTO TAKEN May 10, 1921. 
b, FEMALE GNATCATCHER ON ANOTHER NEST; PHOTOGRAPHED JUNE 10, 1921. 
being only partially shaded, the male was accustomed to stand in it a large 
part of the time during the heat of the day in order to protect the young from 
the sun (fig. 3la). The nest and its surroundings were left in a perfectly 
clean condition. The young remained with the parents until early in August, 
after which the original pair continued to occupy the same territory, while the 
young drifted off together to other hunting grounds. 
A certain degree of individuality was noticeable among the various gnat- 
