146 ANIMAL LIFE OF CARLSBAD CAVERN 



part of these bones were those of the common rodents, 

 such as jack rabbits, cottontails, wood rats, kangaroo 

 rats, cotton rats, pocket gophers, ground squirrels, 

 white-footed mice, grasshopper mice, and pocket mice. 

 Two of the little spotted skunks had been eaten; the 

 Guadalupe meadow mouse was represented by one 

 tooth; a few bats of several species were represented 

 by jaws; while in the big cave considerable numbers of 

 the guano bats had been swallowed whole, one of the 

 pellets shown in the illustration being composed almost 

 entirely of bat bones and fur. Near the river there 

 were feathers and bones of ducks, probably cripples 

 from the hunting season, and in caves in other localities 

 were found a few fragments of bird bones, one of a 

 coot, one of a black-headed grosbeak, one of a sparrow, 

 and one of a towhee. These were so few in comparison 

 with the total number as to be of little economic impor- 

 tance, and formed by no means a regular part of the 

 owl's diet. There were also a few bones of several 

 species of snakes, of three species of lizards, of a horn- 

 toad, and some catfish bones, together with large num- 

 bers of extra legs, and other hard parts of many different 

 kinds of beetles, grasshoppers, moths, and large vine- 

 garoons. Although even the harder parts of many 

 species quickly disappear and with them the evidence, 

 insects apparently formed a far larger and more con- 

 stant part of the owl's food than did birds or reptiles. 

 Aside from the unusual cases of local destruction of 

 bats and white-throated swifts, where found living in 

 dense colonies, the food of these owls is mainly of direct 

 benefit to man. The check on over-abundance of 



