Cross-fostering is a technique to move very young pups from one litter into a different, similar-age litter with the intent that the receiving pack will raise them as their own. Two pups from the six-pup litter of the recently released Coronado Pack female (F1126) were transplanted into the three-pup litter of the Dark Canyon Pack female (F923) on the Gila National Forest in New Mexico on May 15.
Both litters are approximately two-week olds.
This cross-fostering attempt was undertaken to introduce genetically desirable pups into the litter of an experienced female and wild-proven pack. Cross-fostering has been successfully employed in the east coast red wolf recovery program.
F1126 and her offspring are descendants of a genetically underrepresented lineage in the Mexican wolf wild population. F923 is a nine-year-old female that has successfully reared pups in a pack that demonstrates favorable wild behavior.
“We will adaptively manage these wolves in order to produce a population that is not measured by numbers alone, but by genetic robustness, desirable wild behavior and survivability,” said Benjamin Tuggle, the U.S. Fish and Wildlife Service Southwest Regional Director. “Cross-fostering is just one of the management tools we can use to improve the genetic health of the wild population.”
Initial locations indicate that the Dark Canyon wolves continued to utilize the den area.
“Now that we've placed the pups in the den, we will continue to remotely monitor the pack through radio telemetry signals to avoid further disturbance of the Dark Canyon Pack,” said John Oakleaf, Field Projects Coordinator for the Service. “Later, through remote camera observations and efforts to trap the young of the year, we hope to learn whether the cross-fostering attempt was successful.”
F1126 was among two pairs of wolves released by the Mexican Wolf IFT in April in Arizona. She and her mate were identified as the Coronado Pack. Shortly after her April 9 release into the wild, pregnant F1126 and her mate M1249 separated, possibly as a result of an encounter with an already existing pack. M1249 has since been located back in his original territory. F1126 settled in an area south of the release site, and the IFT maintained a food cache for her in the area. F1126 established a den and delivered pups around May 5.
F1126 has no previous experience in the wild, and with no mate to assist her with hunting and rearing the pups, the IFT determined that the pups would not likely survive in the wild based on previous occurrences of inexperienced lone females being unsuccessful in raising pups in the wild.
On May 15, the IFT retrieved F1126 and her pups. While two pups were cross-fostered to the Dark Canyon Pack, the remaining four pups were transported with F1126 to Sevilleta Wolf Management Facility in New Mexico. On May 17, the Service introduced F1126 and her pups to her former mate, M1051, to enable these pups to be reared by both an adult male and female and provide a cohesive pack for translocation to the wild.
Dr. Susan Lyndaker Lindsey, Animal Curator, Mesker Park Zoo and Botanical Garden of Evansville, Ind., was on hand at Sevilleta to oversee the introduction of M1051 to F1126 and her pups. Dr. Lindsey is the Husbandry and Behavioral Advisor to the Mexican Wolf Species Survival Plan, a 53-facility bi-national captive breeding program that manages, breeds, and raises wolves for reintroduction into both the United States and Mexico.
“F1126 and M1051 are behaving as a pair. The male has inspected the den, and the mother is routinely visiting the den to feed the pups,” said Dr. Lindsey. “We’re observing from a distance to minimize disturbance, so it won’t be until pups emerge from the den in approximately two weeks that we can confirm the number that survived.”
If this newly formed pack continues to do well, it is slated for translocation into the Gila Wilderness Area in New Mexico early this summer.
The Mexican Wolf Reintroduction Project is a collaborative effort of the U.S. Fish and Wildlife Service, Arizona Game and Fish Department, White Mountain Apache Tribe, USDA Forest Service, USDA Animal and Plant Health Inspection Service — Wildlife Services, and several participating counties in Arizona.
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