Factors influencing reproduction in captive Vancouver Island marmots: implications for captive breeding and reintroduction programs

Many factors important to reproduction are difficult to quantify for wild mammals, yet an understanding of them is often critical to species' recovery programs, particularly those involving captive breeding and reintroduction. We examined management variables employed by the Vancouver Island man-not captive breeding program during 1998-2005 to determine how such variables influenced production of young and litter sizes. We then tested the ability of factors that were identified as important to predict production of young in the breeding program in 2006. For previously paired animals, production of young was significantly greater when they had been paired with the same mate for >= 1 year before the breeding season. When these females had been with a mate for < 1 year, production of young was more than 2 times greater among 2-4 year olds compared to older age classes. Among previously paired females, 5-7 year olds and those that had produced young previously tended to produce young more often than other categories. Litter size was positively influenced by visual contact between a female and other pairs. For previously paired females, age, the amount of time paired with their mate, and previous production of young accurately predicted 75% of production of young in 2006. We propose that results from out study be combined with genetic considerations to plan future pairings in the breeding program and to assist in the selection of individuals for reintroduction to the wild. Methods reported herein may be applicable to recovery programs for other imperiled mammals.