Vol. 7, Noo 7 
Page 4 
6. Rabbit Management J. A. Bailey, D. A. Casteel 
Reproductive Behavior . -- A study of cottontail reproductive behavior has 
revealed that a dominant male will begin to associate with a pregnant female 
almost constantly as parturition approaches. At the onset of most evening 
periods of activity, the dominant male, and often other males, in a rabbit 
enclosure systematically checked the females by olfaction. The dominant 
male began to associate with pregnant females as early as 3 days prior to 
parturition. This behavior was characterized by an aggressive maintenance 
of as close a proximity to the female as possible and a defense of that 
vicinity against subordinant males. The female seemed to determine how near 
she could be approached and defended the vicinity by attacking all intruders 
and chasing them to the rather sharply defined boundary of her territory. 
This contrasted to the male's defense of the area immediately surrounding the 
female; he was apt to chase an intruder of this area around the entire pen 
one or more times before returning to some pdint near her to resume his vigil. 
As the time of parturition drew nearer the size of the area defended by the 
female decreased, and the social hierarchy between males became more evident 
as competition became keener. 
Marsden and Conaway (1963:167) state that the path the female takes 
after parturition can be deduced by observing the males following along 
the trail evidently by olfaction. Apparently the estrous status of females 
is checked daily by males and when a female is found to be receptive, or 
receptivity is probable, the male attends her until either copulation is 
allowed or the receptivity wanes. This would help to ensure that a male was 
in attendance at the optimum time for breeding. Without the aforestated know¬ 
ledge, one might think that it would be improbable that a male would usually be 
in the vicinity of a newly postparturient female. It is not known how long 
after giving birth the female remains receptive. Holler (Marsden and Holler 
1964:17) states that estrus in the Swamp Rabbit, S. aquaticus , lasts less than 
1 hour, I suspect that the cottontail also is receptive for a short time only 
and that a female would not stray far from the nest searching for a mate. 
This suggests that among cottontails in the wild there is generally a male in 
attendance at the time of parturition and that he immediately services the 
postparturient female. This further suggests and augments Conaway's (Conaway et 
al. 1963) contention that commencing with the onset of the reproductive 
season in late winter, all females of breeding condition are continuously 
pregnant until cessation of the breeding season in late summer. 
Population Dynamics at Allerton . — Differential mortality of marked 
and unmarked rabbits due to hunting, as found in Michigan by Eberhardt et 
al. (1963), is not strongly indicated on the Allerton 4H Area (Table 2). The 
proportion of marked animals in the kill decreased as the season progressed 
only in 1961-62 when an unusually large harvest was made. If marked rabbits 
are especially susceptible to hunting, the trend of 1961-62 should have occurred 
in at least some of the other years, but it did not. This leaves the very 
intriguing possibility that immigration of unmarked rabbits onto the 4H Area 
was especially high in 1961-62 as a result of the very large kill of rabbits 
during the first 20 days of that season. 
