Rapid Homogenization of Multiple Sources: Genetic Structure of a Recolonizing Population of Fishers

During February to mid-March (1988 and 1994-1996), we immobilized adult and yearling moose from helicopters using a dart gun injecting a mixture of an anesthetic and a tranquilizer (ethorphine and xylazine; Sandegren et al. 1987). We equipped each animal with a numbered radio- collar (very high frequency transmitters, model TXH-3; Televilt, Lindesberg, Sweden) and uniquely numbered ear tags. We estimated the age of moose according to tooth wear during the marking event (Skuncke 1949). From females that later died, we retrieved the jaw, sectioned the first permanent molar, and counted the cementum annuli with a 20-40X magnifier (Bubenik 1998). All animal experimentation reported in this paper complied with the current laws regulating the treatment of animals in Sweden and was approved by the appropriate ethical committee (Umed djurfdrsdksetiskanimnd, protocols DNR A-11-91, A-12-91, A-102-93, A-103-93, A-17-94; G6teborgs djur- firs6ksetiskanamnd, protocol DNR 212-97). We followed 20-35 adult moose females by radiotelemetry

each year during 1988 and 1994-1998. We tracked them every third day during the moose calving season (until we confirmed birth) and documented birth rate. In 1994-1997,

we captured a random sample of calves by hand (using gloves). We determined the sex of captured calves, weighed them with a spring scale, and measured skull length with a caliper. We determined age of calves by the frequency of observations of moose females, the condition of the umbilicus, and behavioral characteristics (Larsen et al. 1989). Handling time was <5 minutes, even for twin calves. In 1994 and 1995, we equipped captured moose calves with a 29-g ear-mounted radiotransmitter (Televilt Model TXP-1). In 1996, we equipped the captured calves with a 100-g radiotransmitter attached to an expandable neck collar (Model 305; Telonics, Mesa, AZ). The radio- transmitters had a mortality sensor with a 2.5-hour delay. We investigated mortality sites on the ground to determine the cause of death when we detected a mortality signal. We monitored radiomarked moose calves once a day during the first 5 weeks after marking, every second day during the sixth week, and thereafter once per week for 10 weeks