60 BIRDS IN THEIR RELATIONS TO MAN. 



Sixteen canaries mentioned by Dr. Stanley ' ate one hun- 

 dred grains of food per day, about one-sixth of their own 

 weight. " A gull kept and fed in a garden devoured in one 

 day fourteen mice and two rats. Another was seen to swal- 

 low an entire rat, an operation, however, not accomplished 

 without some difficulty, the bird making several efforts before 

 it succeeded, and even then the tail remained visible for sev- 

 eral minutes." 2 



In The American Naturalist for July, 1899, Dr. Thomas H. 

 Montgomery, Jr., gave some valuable data concerning the food 

 of owls, based on a study of food pellets regurgitated at roosts. 

 In the winter of 1898-99 four long-eared owls took residence 

 in an arbor-vitse tree on Dr. Montgomery's grounds at West 

 Chester, Pennsylvania, and from December 25 till February 

 22 were under his observation. Pellets were gathered weekly 

 and analyzed. In the fifty-nine days the pellets from beneath 

 this one tree yielded remains of two birds, one shrew (Bla- 

 rina), one common mouse (Mus), and three hundred and 

 forty-five field-mice (Microtus). Under a Norway spruce near 

 by, where a short-eared owl roosted regularly and one of the 

 long-eared occasionally, were found between February 26 

 and March 26, twenty-eight days, evidence of one crawfish, 

 five birds, two shrews, one jumping mouse (Zapus), and one 

 hundred and five field-mice. Pellets believed to have come 

 from the same owls, found under trees within a radius of an 

 eighth of a mile, contained remains of five birds (Begulus, 

 Junco, Certhia), seven shrews, and one hundred and forty- 

 eight mice. Taken altogether here "was an equivalent of one 

 owl for two hundred and forty-six days, to which are credited 

 twelve small birds, ten shrews, and six hundred mice, or 

 about two and one-third animals, mainly mice, per day. 



For twenty-two consecutive days, December 25 to January 

 15, Dr. Montgomery counted four owls in the arbor- vitae tree 



1 History of Birds, p. 225. 2 Id., p. 143. 



