530 Life-histories of Northern Animals 



bird here, feeds largely upon them. This owl is diurnal, and 

 may be seen flying low over the surface in search of Meadow- 

 mice, in broad day, both in winter and summer. The hawks 

 all prey upon them, too, from the little sparrow-hawk to the 

 great red-tailed buzzard. The marsh-hawk lives mostly upon 

 them in this region, and is observed sweeping along close 

 to the ground hunting for them in every field. Dr. Hoy 

 informs me that near Racine he observed, in autumn, a flock 

 of black-hawks {Archihuteo sancti-johannis), 20 or 30 in num- 

 ber, to frequent a high knoll to which numerous Meadow- 

 mice had been driven by the inundation of the surrounding 

 lowlands. This they visited morning and evening for over 

 a month, during which time they appeared to feed upon nothing 

 else than Meadow-mice. One of them, shot late in autumn, 

 was exceedingly fat, and had the remains of 4 full-grown arvicolce 

 in his stomach. Dr. Hoy estimated the number destroyed 

 by the flock in six weeks at over 8,000. He says that they 

 form the chief food of this hawk in the West, and that it should 

 be regarded as a friend to the farmer, the more so as it does not 

 make predatory descents on the farm-yard. Arvicolce are the 

 legitimate food of the prairie rattlesnake or massassauga 

 {Crotalphorus tergeminus). In many specimens of this snake 

 examined I have not found one the stomach of which did not 

 contain the remains of Meadow-mice. The rattlesnake can 

 readily enter their burrows, and is certainly more or less noc- 

 turnal; so that the arvicolce, when out at night, fall an easy prey 

 to this voracious reptile, which, though noted for its ability 

 to endure wonderful fasts, even of a year or more, in captivity, 

 is, nevertheless, a huge feeder naturally. I have taken the 

 partly digested bodies of 5 adult arvicolce, with the remains of 

 2 small garter-snakes, and some bird's feathers, from the stom- 

 ach of a rattlesnake, and have repeatedly found the remains 

 of several Mice, in various stages of digestion, in the stomach 

 of one of them, showing that they had been caught at different 

 times. And I would here remark that I have little faith in the 

 opinion popular among farmers that rattlesnakes eat only at 

 long intervals from choice. Observation indicates the con- 



