1918 | Grinnell: A Synopsis of the Bats of California 237 
ENeEmigs oF Bats 
It is axiomatic that the birth-rate of a species is indicative of the 
relative degree of danger to which its individuals are subject. Among 
bats the usual number of young is but one or two at a birth, and but 
one litter is produced annually. Hence it may be taken for granted 
that bats have but comparatively few enemies. Three reasons may 
be advaneed to account for this comparative immunity from enemies, 
namely: the probably unpalatable flavor of bats, as suggested by their 
odor; the comparative safety and remoteness of their diurnal retreats ; 
and the fact that they are both volant and crepuseular. In this con- 
nection it may be observed that a comparatively slow rate of repro- 
duction is to be found also among nighthawks and owls, which like- 
wise fly at twilight or nocturnally. 
C. H. Merriam (in Murphy and Nichols, 1913, p. 10) says: ‘‘ Bats 
have been found in both owl and hawk pellets a number of times, but 
only rarely in hawks’. They have been found also in the stomachs 
of large trout, and it goes without saying that they are sometimes 
discovered and eaten by some of the smaller predatory carnivores.’ 
Seton (1909, p. 1181) says: ‘‘At Chilliwack Lake, in British 
Columbia, the rainbow trout are of great size, eight pounds to twelve 
pounds, and these giants were often seen by Professor John Macoun, 
leaping after the bats that skim the surface of the lake at evening. 
In one ease he thinks he saw a bat captured by the trout, and is satis- 
fied that the fish would not jump so persistently if they did not fre- 
quently sueceed.’’ This is of interest, but obviously inconclusive. 
Fisher (1893) records the results of the examination of the 
stomach contents of 2690 hawks and owls inhabiting the United States, 
including forty-nine species and subspecies. In this list (p. 180) 
we find but one mention of the bat, a single silvery-haired bat 
(Lasionycteris) that was found in the stomach of a great horned 
owl. Altum (1863, pp. 48, 217) records the examination of 703 pellets 
disgorged by European barn owls, among which were found a total of 
2551 skulls, sixteen being of bats. 
Barrows (1884, p. 29), in a paper on birds of the Lower Uruguay 
River, South America, states that at night the deserted corridors of 
the college at Concepcion was one of the barn owl’s favorite hunting- 
grounds for bats. Bailey (1905, p. 211) states that he found two 
lower jaws of the large brown bat in pellets under the nest of a great 
horned owl in Texas. Miller (1904, p. 337), in an article on Cuban 
bats, mentions an individual barn owl which fed largely on bats. 
