Alaskan Polar Bear Movements from Mark and Recovery

Abstract

ABSTRACT. Alaskan polar bear mark and recovery studies from 1967-1976 and concurrent studies elsewhere indicate some interchange of polar bears between Alaska and the mainland coast of northwest Canada, but not between Alaska and the rest of Canada, Gmdand, and Svalbard. The extent of movement between Alaska and the U.S.S.R. remains unknown. The number of Alaskan bears recovered in the same general area as marked suggests that the same animals tend to occur in the same general area in late winter and early spring each year. Distance traveled between marking and recovery sites and the proportion of animals that move to a different area are about the same for bath sexes and for subadults and adults. Bears tend to disperse from commonly used areas in years when ringed seals are less available. The rate of movement in late winter and early spring is about the same for both sexes and for subadults and adults. After mid-April the predominant movement of bearsmorth of Alaska is to the east. Key words: polar bear, Alaska, Arctic, mark-recovery, movement &SUM&

Site fidelity of Svalbard polar bears revealed by mark-recapture positions

“…Seasonal site fidelity of polar bears has previously been reported in the spring (Schweinsburg et al 1981;1982, Lentfer 1983) and year-round (Mauritzen et al 2001). Zeyl et al (2009a showed a population structure in Svalbard in which closely related polar bears were found closer together in space than other bears, indicating restricted movements of both males and females during the mating season.…”

“…Taylor et al (2001) reached a similar conclusion in Canada. Other studies have not been able to detect any effect of age or sex (Schweinsburg et al 1981, Lentfer 1983). This may reflect real differences between the populations investigated, but could also relate to issues of sample size or methodology.…”

“…Hunting statistics, trappers" knowledge, tracks and sightings of marked and unmarked animals were important in acquiring early knowledge of polar bear distribution (Lønø 1970, Larsen 1986, Taylor and Lee 1995. Markrecapture and mark-recovery studies have shown that bears tend to return to the areas in which they have been tagged rather than venture into neighboring areas (Lentfer 1983, Larsen 1986). Delineation of the polar bear"s circumpolar range into 19 currently recognized subpopulations (hereafter called populations, for simplicity) has for the most part been confirmed and refined using telemetry (Bethke et al 1996, Taylor et al 2001, Obbard et al 2010) and genetic methods (Paetkau et al 1995;1999).…”

“…Site fidelity may refer to a very specific location or area, such as a nesting site or a territory (Greenwood 1980). What some refer to as an area (Lentfer 1983) others might refer to as a region (Ferguson et al 1997). Polar bears are non-territorial, and most of their activities relate to unbounded areas rather than to defined areas or single points in space, with the exception of maternal denning (Amstrup 2003).…”

“…Furthermore, they found that subadults moved farther than adult bears (Taylor et al 2001). An early study in Alaska did not find any age and sex differences, but used a much coarser measure, the likelihood of being recaptured in the same area (Lentfer 1983).…”