L12 



THE AMERICAN NATURALIST [Vol. XL V 



for which statistics are given below, not a single bird was 

 killed by a fox so far as is known. Similarly in 1909 no 

 birds were killed by skunks. In 1910 a skunk succeeded 

 in getting into a house one night and killed a number of 

 birds. On the Maine Station plant normally predaceous 

 birds undoubtedly rank first in destructiveness. This is 

 probably quite generally true of poultry plants, though 

 because of the fact that the loss is distributed so evenly 

 over the whole season the importance of this class of 

 enemies is apt to be underrated. Next to predaceous 

 birds stand rats, under our conditions. An important 

 point to be noted is that on the plant under discussion 

 here all killing of chickens by rats is done in the daytime. 

 Rats burrow in the ground under the houses, and then 

 when the chicks are playing about a rat will dash out, 

 seize a chick and carry it back to the burrow. It is not 

 an uncommon occurrence for a rat thus to kill as many 

 as 12 chickens within the space of an hour. With rare ex- 

 ceptions we never lose any chickens at night except those 

 taken by thieves. The chicks are shut and locked in rat 

 and (usually) vermin proof houses at night. Occasion- 

 ally, as noted above, a skunk is able to effect entrance 

 into a house. This, however, did not happen in 1909, the 

 year which furnished the statistics given below. It 

 should be clearly understood that in the statistics which 

 follow all "eliminations" occurred in the daytime, when 

 color and pattern might presumably be of some signifi- 

 cance. 



It is my purpose to present some statistics, involving 

 a relatively large number of individuals, regarding the 

 relation of color pattern to the elimination of chickens 

 by all of these natural enemies taken together. These 

 statistics cover the hatching season of 1909 in which 

 chickens were on the range, and subject to the attacks 

 of enemies, from about April 1 to October 1. Birds of 

 all colors and patterns ran together on the same open, 

 turf-covered range, and. without regard to color or pat- 

 tern, all were equally exposed to attack by all sorts of 



