Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Factors Influencing Reproductive Success and Litter Size in Captive Island Foxes

ELIZABETH S. CALKINS, TODD K. FULLER, CHERYL S. ASA, PAUL R. SIEVERT and TIMOTHY J. COONAN
The Journal of Wildlife Management
Vol. 77, No. 2 (February 2013), pp. 346-351
Published by: Wiley on behalf of the Wildlife Society
Stable URL: http://www.jstor.org/stable/23361292
Page Count: 6
  • Download ($42.00)
  • Subscribe ($19.50)
  • Cite this Item
Preview not available
Preview not available

Abstract

A severe decline of island foxes (Urocyon littoralis) on the northern Channel Islands in the 1990s prompted the National Park Service to begin a captive breeding program to increase their numbers. Using detailed records of all the fox pairs (N = 267) that were part of the program on San Miguel, Santa Rosa, and Santa Cruz Islands from its inception in 2000 through 2007, we identified factors influencing the breeding success of pairs in captivity in the interest of formulating strategies that could increase captive productivity. We compiled a database of variables including litter size, reproductive success, distance to nearest occupied pen during the breeding season, subspecies, exposure, female age, male age, age difference, female and male origin (wild vs. captive born), same versus different origin, years paired, previous reproductive success by the pair, previous reproductive success by the female, mate aggression-related injuries, male previous involvement in a pair with mate aggression, and female previous involvement in a pair with mate aggression. We used multiple linear regression to identify factors predictive of litter size, and logistic regression to predict the probability of reproductive success. A larger inter-pen distance, older male age, less exposure, and a smaller intra-pair age difference positively affected litter size. The probabilities of reproductive success increased with fewer years paired and less exposure. Comparatively, pairs with wild born females (vs. captive born females), and previously successful pairs (vs. previously unsuccessful and new pairs) were most likely to be successful. These results indicate that the optimal situation was to pair wild-caught females with older males in sheltered pens that were as far from other pens as possible, to maintain successful pairs and repair unsuccessful ones. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Page Thumbnails

  • Thumbnail: Page 
346
    346
  • Thumbnail: Page 
347
    347
  • Thumbnail: Page 
348
    348
  • Thumbnail: Page 
349
    349
  • Thumbnail: Page 
350
    350
  • Thumbnail: Page 
351
    351