174 THE CONDOR Vol. XXIII 
ever, remained in the nest an hour or two longer than the others (fig. 29b). 
The four were seen together in the neighborhood for some time. 
About March 1, 1921, a pair of gnatcatchers (possibly from the brood just 
mentioned, which had passed the winter in the vicinity) started a nest near the 
top of a low sumae bush (Rhus lawrina) about 244 feet from the ground. The 
work proceeded rapidly at first, most of it being done by the male, and then 
gradually slowed up. By the middle of the month the nest, which was ready 
for the lining, seemed to be deserted, and a week later was found overturned 
and partially destroyed. This suggested a search for a new nest, which was 
found a day or two later about 125 feet away in a clump of cactus and weeds 
and about two feet from the ground. It was complete except for part of the 
lining, which was added to from time to time until finished, after which the 
birds showed no further interest in it. 
Fig. 28. HABITAT OF THE BLACK-TAILED GNATCATCHER, SAN GABRIEL WASH, 
NEAR AZUSA, CALIFORNIA; PHOTOGRAPHED JUNE 30, 1921; A NEST WAS SIT- 
UATED IN THE CENTER OF THE LOW BUSH IN THE RIGHT FOREGROUND. 
On April 22, by following the male gnatcatcher for a while, I located a 
third nest in a buckthorn bush (Rhamnus crocea) about 250 feet from the last 
The site was much the best of the three, being about 21% feet from the ground 
and in the midst of such a thick mass of twigs that the nest could not be clearly 
seen from any direction (fig. 30a). There were three eggs, grayish or bluish 
white speckled with reddish brown. The duty of incubation was divided be- 
tween the two parents and the eggs were seldom left uncovered even for a 
moment. The birds showed no resentment at the presence of a human specta- 
tor, though the approach of another bird within perhaps fifty feet of the nest 
was often the cause of fierce demonstrations on the part of the male gnat- 
! 
vr 
