236 University of California Publications in Zoology  [Vou.17 
the non-migratory species which remain on the wing throughout the 
year seem to rely in good part upon such stored fat to help tide them 
over the winter months, during which flying insects are available in 
but seanty numbers. 
Breeding Habits——I have been able to collect data which show the 
number of young in most of our species of bats, and the approximate 
time of birth, but the time and extent of the mating season is still 
unknown. According to Barrett-Hamilton (1911, pp. 31-32), Messrs. 
Rollinat and Trouessart have established the fact that in France the 
normal mating time is autumn. Barrett—Hamilton says: 
At that season spermatozoa are found numerously in the uterus of the adult 
female, and the organs of the male are also functional. Ovulation is, however, 
postponed until the termination of hibernation, during which period the ovaries 
are quiescent, but the spermatozoa retain their activity in the uterus until 
fertilisation takes place, in April. On this point all authorities are agreed, and 
the facts, subject to correction as to details, may be taken as substantiated. An 
alternative view, that ovulation and fertilisation may take place in the autumn and 
winter, with subsequent postponement of the development of the embryo, seems 
to be unsupported by facts. 
Recorded observations of autumnal mating in certain species of the 
eastern portion of the United States incline one to the belief that 
nearly related races occurring in California may possess similar habits. 
Murphy and Nichols (1913, p. 11), writing upon the bats of Long 
Island, confirm earlier reports of autumnal mating in the eastern red 
bat (Nycteris borealis borealis). 
VOICE 
As is well known to all naturalists, the voices of bats are high and 
shrill; in other words, the vibrations are of high frequency. Barrett- 
Hamilton (1911, p. 43) states that a young bat calls for its mother as 
persistently as any other young animal, and in commenting upon the 
shrillness of the voices of bats suggests that some of their cries are 
pitched on a higher seale than that to which any human ear is attuned. 
At least two gregarious bats, Antrozous and Nyctinomus, are quite 
noisy in their daytime haunts, squeaking almost continually as they 
jostle one another restlessly. Coues (1867, p. 284) mentions the 
squeaking and scratching of Antrozous pallidus in the chinks of the 
officers’ quarters at Fort Yuma. When sleeping out-of-doors near 
a loft oceupied by a colony of Pacifie pallid bats, the present writer 
has often heard their shrill voices far into the summer night. 
