BREEDING SEASON. 29 



any jack rabbits are bora before the 1st of February in California west 

 of tlie Sierra, or before tlie 1st of April north of Kansas and central 

 Nevada. The length of the breeding season in somthern regions indi- 

 cates that several litters are born each year, but in the northern United 

 States the number is probably not more than two, or at the most, three. 



The practical bearing of these generalizations is obvious. Drives or 

 hunts organized for the extermination of rabbits should take place 

 before the beginning of the breeding season, if they are to accomplish 

 the desired end. Just after the young are born the rabbit population 

 in a given i)lace may be two or three times what it was six weeks pre- 

 vious, and the killing of 1,000 rabbits then would be only one-half or 

 one-third as effective as the destruction of an equal number earlier in 

 the season, when all the animals were adults. Drives in southern Cal- 

 ifornia should therefore be made in December, January, February, or 

 early in March — the earlier the better, if the weather .is favorable; 

 later in the season more rabbits may be killed at one time, but a cer- 

 tain proportion will be young. In Colorado and Utah, hunts made 

 before the 1st of February will accomplish much more than those in 

 April, while in Idaho they may be postponed somewhat later. 



Similarly, when killed for game, the rabbits from southern California 

 or Arizona are not likely to be in the best condition after the 1st of 

 February or March, while those from the northern Plains may be 

 shipped up to the 1st of April. On the other hand, the young will 

 hardly be in condition for market before October except in southern 

 regions, and there the hot weather is likely to interfere with their ship- 

 ment. 



