Translocation of Swamp Rabbits in Southern Illinois

Habitat of Sylvilagus aquaticus (swamp rabbits) in Illinois has been reduced and fragmented due to human land use. Translocation may enable swamp rabbits to colonize isolated habitat patches. We live-trapped and translocated 9 male and 8 female swamp rabbits to unoccupied habitat in southern Illinois in January and February 2004. Eight of 17 translocated rabbits died within 7 days after release. However, mortality rates appeared to drop rapidly over time after release. Predators killed at least 10 of 14 rabbits that died. For conserving swamp rabbits, translocation success is limited by poor live-trapping success and high levels of post-release predation. Intense live-trapping along with predator control in release sites may be necessary to make translocation a viable management strategy

Cyclicity in Northern Bobwhites: A Time-Analytic Review of the Evidence

Cyclical behavior in wildlife populations, including northern bobwhite (Colinus virginianus), has long fascinated human observers. However, studies examining cyclicity of bobwhite abundance have yielded contradictory results. We reviewed evidence for periodic fluctuation in bobwhite abundance by studying 73 long-term time series. Our aim was to discern with time-series techniques whether cyclicity occurred in bobwhite abundance. We elucidated the frequency of occurrence, geographical distribution, and potential mechanisms responsible for cyclicity. Approximately one-half (n = 37) of the populations examined demonstrated cyclical behavior, with a period varying between 4 and 17 yrs. True cycles, consistent, significant fluctuations in abundance, were rare, occurring in only 3 time series. The predominant form of periodicity was of the phase-forgetting quasi-cycle type (n = 34). This phase-forgetting may have contributed to previous contradictory findings of cyclicity in this species. We reason cyclicity in bobwhite populations is caused by aperiodic environmental perturbations interacting with density-dependence. Cyclic bobwhite populations occupied the northern and western portion of the species’ range, where stochastic weather events regularly negatively influence bobwhite population dynamics. Bobwhite populations were non-cyclic in the relatively consistent climate of the southeastern United States, however, habitat fragmentation rather than climate may have contributed to the absence of cyclicity in this region