1 July 2005 Dispersal and Survival of Juvenile Beavers (Castor canadensis) in Southern Illinois
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We used radiotelemetry to estimate natal dispersal patterns and survival rates of 13 yearling and 19 subadult beavers (Castor canadensis) at two geomorphologically different sites in southern Illinois. Overall, we observed a 55% dispersal rate for yearlings and a 73% dispersal rate for subadults. Normally, juveniles (yearlings subadults) initiated dispersal around 16 February (range = 28 Jan.–20 Mar.) and settled around 18 April, with juveniles remaining transient from late January through late June. Nine subadult beavers dispersed significantly earlier at one site (x̄ = 25 Nov., range = 31 Oct.–16 Dec.), presumably due to intra-colony strife brought on by management-induced autumn flooding of wetlands for waterfowl. Dispersal occurred earlier than documented in northern regions. Beavers dispersed farther from natal colonies with free-flowing water access (x̄ = 5.9 km) than those landlocked (x̄ = 1.7 km). Males moved more frequently and traveled greater distances per individual move than did females, but overall dispersal distances were similar between sexes. Dispersal distances of beavers with access to free-flowing waterways generally were similar to other studies. Survival during dispersal was greater for beavers emigrating from lodges on the land-locked, less densely populated site (0.80), than for those dispersing in an area of higher population densities (0.43), but did not differ between dispersers and non-dispersers at either site.

LANCE B. McNEW, Jr. and ALAN WOOLF "Dispersal and Survival of Juvenile Beavers (Castor canadensis) in Southern Illinois," The American Midland Naturalist 154(1), 217-228, (1 July 2005). https://doi.org/10.1674/0003-0031(2005)154[0217:DASOJB]2.0.CO;2
Accepted: 1 December 2004; Published: 1 July 2005
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