The Oregon Silverspot Butterfly Project w Bat Studbooks w Field Conservation

The Oregon Silverspot Butterfly Project
By Mary Jo Andersen, Blair Csuti and David Shepherdson

The Oregon silverspot butterfly (Speyeria zerene hippolyta) is the only Oregon insect listed as threatened under the U.S. Endangered Species Act. Once found in coastal headlands from northern California to southern Washington, it has disappeared from all but a handful of sites along the Oregon coast. In addition to habitat losses, one possible factor in its decline has been fire suppression, which allows grass to overshadow its obligate larval host plant, the western blue violet (Viola adunca).

The Nature Conservancys 280 acre Cascade Head Reserve in southern Tillamook County is home to one of the surviving populations. During the last ten years, butterfly monitoring at Cascade Head has shown a dramatic decline in the number of butterflies seen flying. From an average of over 1,000 adults seen most years prior to 1992, only 57 butterflies were recorded in 1998. In response, The Nature Conservancy (TNC) has initiated a habitat management plan that will use controlled burning to increase host plant populations. For the next several years, however, while the population hovers near extinction, TNC, the Oregon Zoo, and Lewis and Clark College have embarked on a butterfly rearing program designed to maintain genetic variability in the population and increase the likelihood of its natural recovery.

This fall, a total of ten female butterflies were brought from Cascade Head and induced to lay eggs in laboratories at the Zoo and Lewis and Clark College. Each facility housed five butterflies that were captured toward the end of their life cycle, with the intent that they would have already bred and laid some eggs in the field before being brought into captivity. Every day, the butterflies were fed nectar, a solution of sugar water and egg white, by placing them on saturated cotton balls.

The eggs were collected daily, and put into separate petri dishes. After approximately ten days, many of the eggs hatched out into tiny larvae. Each larvae is about two millimeters long, and under a microscope, can be seen to be a perfect miniature caterpillar! At this stage, the larvae do not eat, but they were given drinks of water by placing them on moist filter paper. After drinking, they were placed in custom made alder boxes, and put into a refrigerator for winter diapause, or hibernation. We had a total of 200 larvae hatch here at the Zoo.

Following a winter dormancy, the butterfly larvae will be fed Viola leaves until they are large enough to be returned to Cascade Head. Dr. Paulette Bierzychudek, from Lewis and Clarks Biology Department, will help grow western blue violets in her greenhouse. Violets are also being grown at Wildlife Safari in Winston, Oregon. We may raise some larvae to pupae and return them to Cascade Head ready to emerge as adult butterflies.

This conservation technique, called population supplementation is intended to prevent inbreeding depression often seen in small populations. We hope that improved habitat at Cascade Head will allow the butterfly to quickly recover its numbers and put us out of the butterfly rearing business. In the meantime, this U.S. Fish & Wildlife Service-funded cooperative project may be the butterflys best hope for short-term survival.

Bat Studbooks help maintain healthy populations
By Anna Michel, Animal Keeper and Straw Colored Fruit Bat Studbook Keeper

Studbooks are a basic tool in the American Zoo and Aquarium Associations (AZAs) efforts to maintain captive populations. A Studbook is a pedigree, or genetic record for a group of animals, or more simply, a list of who begat who. Studbooks are used as the basis for genetic analysis and planning the management of a given species. If its a species with a Species Survival Plan (SSP), the studbook will be the basis for an intense management effort usually aimed at keeping a captive population with 90% of its original genetic variability for 100 years. Other species that need careful management, but not as big an effort as an SSP, have a Population Management Plan (PMP). This is a less rigorous plan usually managed by the Studbook keeper.

Oregon Zoo currently has five Studbook keepers maintaining seven Studbooks: for Asian elephants, three species of duikers, siamangs, pumas, impalas, white faced saki monkeys, and straw-colored fruit bats.

The Straw-colored fruit bat is a PMP species. The Bat Taxon Advisory Group (TAG) has determined that Straws are a good exhibit and educational species that should be kept in zoos even though they are plentiful in the wild. We dont need to breed them as a last-ditch effort to save the species, but simply want to keep a healthy captive population. With that in mind, the Bat TAG determined that a studbook was needed and in 1995, recommended me as the studbook keeper.

This was the first time that records for all Straw-colored fruit bats in North America had been gathered. I had to start at the beginning, as many new studbook keepers do, with little more than a list of zoos that had straws, and a few leads on some that were privately owned. All those zoos had to be contacted to find out how many bats they had, what the ages and sexes were, who each bats parents were and where they came from. That led to names of more zoos who had these bats and more places to contact. There were times when information from one place contradicted information from another. Other institutions had no written records of their bats and years of verbal history had to be sorted through for accurate information.

Accuracy is critical for a management plan to be formed, so AZA trains studbook keepers to follow a consistent set of guidelines in their search for the truth. In the Straws case, that meant lots of unknowns in the record where no information is better than bad information. The bats were easier than many species; they had only been in captivity in this country for about 20 years. The Puma studbook, for example, goes back 125 years, with about 3500 individuals historically in 365 institutions. I love to get the bats names when they have them. Its a great tool for records, and reminds me that there are other keepers out there taking great care of their bats.

The first Straw-colored fruit bat Studbook was published last year. It is naturally already out of date as new bats are being born. As an added complication, new genetic research indicates that it may not safe to assume that we can tell which baby goes to which mother and that some males may not be fathering any offspring. Updates are published annually and changes may have to be made as genetic studies provide new information.

With some further training and as much expert help as I can find, I will form a management plan for the Straw-colored fruit bat. My goal will be to make sure that the captive population in North America says genetically viable (not inbred) and that numbers stay appropriate to the space we have available.

Oregon Zoo's Growing Role in Field Conservation
By Blair Csuti, Conservation Program Coordinator, Oregon Zoo

Dr. Michael Hutchins, American Zoo and Aquarium Association (AZA) Director of Conservation & Science, made a surprising announcement at AZAs 1999 Annual Conference: taken collectively, the number of field conservation projects of AZAs 185 member institutions exceed those of any other North American conservation organization, including such conservation giants like the World Wildlife Fund. Your zoo is part of this effort and is rapidly expanding its field conservation activities both abroad and in the Northwest.

In 1995, The Oregon Zoo Foundation (OZF) established a Conservation Fund that distributes $20,000 annually to projects that contribute to the survival of populations of free-living animals and the ecosystems in which they are found. During the past two years, projects supported by OZFs Conservation Fund included:

• Sex differences in parental investment of Humboldt penguins at Punta San Juan, Peru.
• Monitoring 1999 Humboldt penguin nesting success at Punta San Juan, Peru.
• Rodrigues Fruit Bat Environmental Education Project, Rodrigues, Mauritius.
• African elephant chemoreception field research at Samburu Reserve, Kenya.
• International Snow Leopard Trust Project Partner, Ladakh, India.
• Creation of a data base of captive and semi-captive primates in Colombia.
• Surveys and monitoring of nesting behavior for populations of western painted (Chrysemys picta belli) and western pond (Clemmys marmorata marmorata) turtles at Burlington Bottoms, Oregon.
• The stress response in Humboldt penguins in Peru and Chile: How much does habitat and body condition matter?
• Endangered turtles of Hainan Island, China.
• Schools awareness program for elephant conservation in Sri Lanka.

The Zoo is also embarking on field conservation work in our own backyard, focusing on cooperative projects that will help declining or endangered Northwest species. In addition to the Oregon silverspot butterfly project these include: