Nov., 1922 THE DEVELOPMENT OF YOUNG COSTA HUMMINGBIRDS 193 
ject by means of a mirror. She had no fear of the camera, however, and once 
returned to the nest while my head was under the focusing cloth. 
In no ease have I seen a male hummingbird in the vicinity of the nest or in 
any way showing interest in the matter. In fact, all the males had apparently 
started on their southward migration by the middle of June, 1922, or soon after 
the eggs had been laid in the last nest and while the young in the second nest 
were no more than half grown. None was seen earlier than May, probably on 
account of the lateness of the season, so their stay was very short this year. By 
July 1 the females and young were also noticeably scarcer. If the owner of the 
third nest had remained to hatch out and rear her young she would probably 
have been detained beyond the usual time for migrating. 
Despite the small size of the hummingbirds, and of the Costa in particular, 
the eggs and young as well as the adults must be peculiarly immune to depreda- 
tions of natural enemies, as evidenced by their survival in the face of several 
unfavorable conditions brought out in the foregoing notes and which may be 
enumerated as follows: First, only two eggs are laid and presumably only one 
brood raised each year by the Costa Hummingbird; second, the period during 
which the young are confined to the nest is from 50 percent to 100 percent 
greater than in the case of the smaller passerine species; third, the young are 
entirely dependent upon the female parent for sustenance. That the humming- 
birds are able to maintain their numbers under these handicaps can but increase 
our admiration for these tiny but highly specialized and intelligent creatures. 
Los Angeles, Califorma, August 21, 1922. 
EVIDENCE OF MUSICAL “TASTE” IN THE BROWN TOWHEE 
By RICHARD HUNT 
O BEGIN WITH I wish to establish in the minds of those readers who do 
EL. not happen to be familar with the Brown Towhee (Pipilo crissalis crissa- 
lis) a working idea of this bird’s song. The song is normally a staccato 
series of sharp metallic clinks with intervals constantly decreasing so as to carry 
the utterance into a thrill or vibration toward the end. The ‘‘shape’’ can be 
easily imagined by thinking of some resilient object, say a golf ball, dropped 
on a hard surface and allowed to bounce itself motionless, thus: tip tap 
tip—ip-prrrrr. A very good idea of the timbre can be gained by striking to- 
gether two silver dollars so as to produce a smart and rather ‘‘live’’ ring. 
Except in two instances, which I am about to describe, I never was struck 
by any signs of instability in the Brown Towhee’s song. On the contrary I had 
come to consider the song so stereotyped that it would be absurd to expect any 
marked individual divergences. ‘‘Brownie’’ had become in my mind a dull 
fellow, musically, particularly devoid of originality. It was refreshing, there- 
fore, to hear first one and then another individual of the species sing a song that 
was decidedly ‘‘off color’’—not, mind you, in any trivial matter of mechanics 
due to inexperience or adventitious defect of execution, but in what I may eall 
subject matter. Both of these ‘‘aberrant’’ singers that by good fortune came 
to my notice departed from the type utterance of their race by adding some brand 
