200 
Vol. XXII 
NESTING OF THE OLIVE-SIDED FLYCATCHER IN 
BERKELEY, CALIFORNIA 
By JOSEPH DIXON 
WITH THREE PHOTOS 
HE OCCURRENCE of tie Olive-sided Flycatcher (Nuttallornis borealis) 
in the San Francisco Bay region in summer has been noted by a number 
of observers (for example, Fisher, Condor, VI, p. 108; Grinnell, Condor, 
XVI, p. 32; and Hansen and Squires, Condor, XIX, p. 60). While this boreal 
v 
Fig. 38. NEST SITE OF OLIVE-SIDED FLYCATCHER 
IN MONTEREY CYPRESS. THE TAIL OF THE FE- 
MALE, ON THE NEST, SHOWS AS A BLACK DOT AT 
THE POINT WHERE THE. MARGINAL ARROWS 
WOULD INTERSECT. 
species has thus already been 
regarded as a breeding bird 
of the Bay region, yet exact 
breeding evidence in the 
form of nests, eggs or young 
appears to be lacking. 
Through the interest and ini- 
tiative of Donald D. McLean, 
a Cooper Club member, defi- 
nite breeding data is now 
available, he having discov- 
ered the nest and eggs now 
to be described. 
On June 12, 1920, a set of 
four slightly incubated eggs 
of the Olive-sided Flycatch- 
er, together with the nest at- 
tached to the limb support- 
ing it, and accompanying 
photographs, were secured 
by Mr. McLean and the 
writer from a slender Mon- 
terey cypress that stands on 
the south-facing hillside just 
north of the Claremont Ho- 
tel, in Berkeley. The birds 
had started a nest in an ad- 
joining cypress, but for 
Some unknown reason they 
had abandoned it and moved 
to the new location. The 
nest was placed fifty-seven 
feet above the ground, by 
actual measurement, and 
thirty inches from the tip of a 
long slender upper branch of 
a broken-topped cypress. The 
Situation was exposed, but 
