REINTRODUCTION PROGRAM UPDATES
Conservation and Research for Endangered Species
Zoological Society of San Diego
August 2007

California Condor
The overall goal of this binational reintroduction effort is to reestablish California condors in the southernmost portion of their former range, as recommended in the U.S. Fish & Wildlife Service California Condor Recovery Plan. The field effort began in 2002 with an initial release of three birds in the Sierra San Pedro Martir Mountains of Northern Baja. Currently, 16 birds are flying free, with four birds in holding pens awaiting release. In the spring of 2007, courtship displays were seen by two potential pairs that resulted in egg-laying for one of the pairs. Unfortunately, the pair chose to use a former golden eagle nest that had a high parasite load, and the chick died within a few days of hatching.

There were two mortalities in 2006, one of which resulted from ingesting lead from a non-proffered carcass. During the best flying months, June and July, the satellite-telemetered condors ranged over 200 miles north to south, and one bird crossed the Mexico-U.S. border. We hope to reach our goal of more than 20 free-ranging birds reestablished in Baja within the next three years.

San Clemente Loggerhead Shrike
The critically endangered San Clemente loggerhead shrike has been the focus of a recovery effort that began in the early 1990s. To recover this subspecies, found only on the Navy-owned San Clemente Island, the U.S. Navy has assembled a diverse, highly cooperative group that has included the U.S. Fish & Wildlife Service, Center for Reproduction of Endangered Species (CRES)/San Diego Zoo, the Institute for Wildlife Studies, PRBO Conservation Science, and San Diego State University’s Soil Ecology and Restoration Group.

These collaborating organizations provide interlocking parts of a complex recovery effort including a captive-breeding program that provides individuals to augment the wild population and also acts as a reservoir against loss from unforeseen disasters; a highly successful release program; year-round field monitoring of the wild population; predator control and management; and a habitat-restoration project. During the 1990s, the project achieved great advances in captive breeding. Successful artificial incubation and hand-rearing protocols were developed, and behavioral management led to successful parent rearing by captive pairs.

Since 1999, the focus has shifted to the development of a variety of release protocols that resulted in successful recruitment of captive-bred shrikes into the wild breeding population. From a wild breeding population of approximately four females and eight males in 1998, we have grown the population to as many as 50 breeding pairs in recent years. Through careful captive breeding and selective release, we have also increased the genetic diversity and nearly equalized the representation of founder lineages in both the captive and wild populations.

Mountain Yellow-legged Frog
The southern California populations of the mountain yellow-legged frog were listed as endangered by the U.S. Fish & Wildlife Service in 2002. Despite this protection, these frogs continued toward extinction, with only seven remaining populations known in southern California, each ranging from seven to 75 adults. Due to the immediate risk of extinction, regulatory agencies decided the rapid establishment of a captive-breeding program was warranted.

In collaboration with the California Department of Fish & Game, U.S. Fish & Wildlife Service, U.S. Forest Service and U.S. Geological Survey, CRES/San Diego Zoo will be primarily responsible for captive propagation of the species. The goal is to establish an integrated program of captive propagation, head starting and release that will ensure the long-term viability of the species in the wild. In August 2006, 79 tadpoles were emergency-salvaged from a drying streambed and transferred to the care of CRES. Some of these will be head started and released back to the wild when conditions are deemed appropriate while others will remain to establish a captive-breeding program once they reach reproductive age. We plan to head start tadpoles until two years of age; after they reach a less-vulnerable stage in their life cycle, they will be released back to the wild.

Pacific Pocket Mouse
The aim of the Pacific pocket mouse project is to use translocation to aid in the recovery of this highly endangered mammal. The species was believed extinct until a few individuals were discovered by U.S. Fish & Wildlife Service biologists in 1993. It is thus a high priority for conservation efforts.

Because translocations often fail, researchers at CRES/San Diego Zoo aim to use information on the species’ behavioral ecology and natural history to design improved translocation methodology. The Pacific pocket mouse is a solitary semi-fossorial nocturnal rodent that is also one of the smallest mammals in North America (~6.5g). Due to its small size, solitary behavior and the fact that it has a very short active period above ground (60­–90 days), almost nothing is known about it.

By attaching tiny radio-transmitters to the animals, CRES staff will test the relative successes of animals released into habitat similar to or different from their natal habitat, using dispersal distance, settlement patterns, stress response and survival rates as measures. Finally, the study will address other factors, such as the number of animals released together, their kin relationships and level of familiarity with one another, as these factors have been shown to dramatically affect post-release success. This project is partially funded by the U.S. Fish & Wildlife Service.

Hawaiian Forest Birds
The Hawaii Endangered Bird Conservation Program (HEBCP) is a unique conservation partnership composed of CRES/San Diego Zoo, government agencies (U.S Department of the Interior and the Hawaiian Department of Land and Natural Resources), and Hawaii’s private landowners, all of which work together to recover Hawaii’s most-threatened forest birds. This program clearly demonstrates the significant role that captive propagation can play as part of a collaborative, multidisciplinary approach to endangered species recovery.

The HEBCP focuses on the augmentation of wild bird populations while effective research and land management measures are being developed to ameliorate threats. The captive-propagation program, which provides birds for reintroduction efforts, is based on many years of technological advances in zoos and private aviculture. From 1993 to the end of 2006, a total of 712 chicks and goslings have been successfully raised to independence at the Keauhou and Maui Bird Conservation Centers. Of these birds, 623 have been released.

Captive-reared palila return to their release aviary on Mauna Kea as part of the “soft release” process.	Captive-reared puaiohi travel in a six-pack transport box to their release site in the Alakai Swamp on Kauai.

Current species managed by the program are the `alala, Maui parrotbill, puaiohi, palila, Hawaii creeper, Hawaii akepa, akohekohe and nene. Intensive release programs exist for the puaiohi, palila and nene; restoration programs for other species are in their developmental stages. No other conservation program in the world has established a propagation/release record for passerines that compares with the accomplishments of this program.

For more information on these programs, visit http://cres.sandiegozoo.org.