A record 22 captive-born Mexican wolf pups were placed into wild dens to be raised in the wild by their surrogate parents after another successful cross-foster season. For six years, wild Mexican wolves have been raising captive-born pups as their own, helping to boost the genetic diversity of this endangered subspecies and moving the wild population towards recovery.
During April and May, nine pups were fostered into three different packs in eastern Arizona and 13 were fostered into five packs in western New Mexico.
“Fostering is an outstanding example of a working private-public recovery program. Wolf recovery has to recognize the importance of meeting genetic criteria, which requires many private organizations maintaining captive wolves for release into the wild. Without this important partnership, genetic recovery would be essentially impossible,” Jim deVos, Arizona Game and Fish Department (AZGFD) Mexican Wolf Coordinator, said in a statement. “Importantly, we are now seeing Mexican wolves that have been fostered producing litters themselves, supporting the use of fostering as an effective conservation tool.”
Cross-fostering is a proven method used by the Mexican Wolf Interagency Field Team (IFT) to increase genetic diversity in the wild Mexican wolf population. It involves placing genetically diverse pups that are 14 days old or younger from the captive breeding population into wild dens with similarly aged pups to be raised in the wild by experienced wolves. The IFT has documented that cross-fostered pups have the same survival rate as wild-born pups in their first year of life (about 50%).
“The U.S. Fish and Wildlife Service remains committed to improving the health of the wild population of Mexican wolves, and cross-fostering is one of the many tools we are using to make progress in that direction,” said Allison Greenleaf, biologist with the U.S. Fish and Wildlife Service. “To see this program continuing to have success is a true testament to the hard work of all our field staff and partners.”
Five different captive-born litters provided Mexican wolf pups for fostering into the wild population. The following facilities provided pups this year:
Endangered Wolf Center in Eureka, Missouri: one litter provided two pups into the Owl Canyon Pack in New Mexico and three pups into the Elk Horn Pack in Arizona; a second litter provided three pups into the Lava Pack in New Mexico and three pups into the Hoodoo Pack in Arizona;
El Paso Zoo in El Paso, Texas: one litter provided three pups into the Castle Rock Pack in Arizona and one pup into the Leon Pack in New Mexico;
Sevilleta National Wildlife Refuge, U.S. Fish and Wildlife Service, in Socorro, New Mexico: one litter provided two pups into the San Mateo Pack in New Mexico and two pups into the Leon Pack in New Mexico; a second litter provided three pups into the Dark Canyon Pack in New Mexico.