Zoo-Raised Smooth Green Snakes Reintroduced to the Wild

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Zoo-Raised Smooth Green Snakes Reintroduced to the Wild

Jul 1, 2011

CONTACT: Sharon Dewar

Zoo-Raised Smooth Green Snakes Reintroduced to Wild in Lake County

Collaborative effort between Lincoln Park Zoo and Lake County Forest Preserve District aims to recover the snake identified as an Illinois Species in Greatest Need of Conservation

Chicago (June 30, 2011) – Six tiny, brightly-colored juvenile smooth green snakes were released into the wild June 30 in a Lake County forest preserve. An exceptionally small insectivore, these snakes are difficult to spot in their grassland prairie habitat. They are also difficult to find because they have become so rare in Illinois. A collaborative conservation effort between Lincoln Park Zoo and Lake County Forest Preserve District (LCFPD) aims to boost their population numbers through scientific study, breeding, monitoring and reintroduction efforts.

According to the Illinois Comprehensive Wildlife Action Plan and Strategy, the smooth green snake is identified as a Species in Greatest Need of Conservation. Populations of this species are declining due to habitat loss, conversion of grasslands into agriculture, urbanization, and the widespread use of pesticides. "Currently, Illinois only has less than one percent of its pre-settlement prairie acreage remaining, so species that depend on grasslands are in need of conservation," said Lincoln Park Zoo Reintroduction Biologist, Allison Sacerdote, Ph.D.

Lake County Forest Preserves Wildlife Biologist Gary Glowacki explained that for more than a decade the district has purchased and/or restored a significant amount of lands containing suitable smooth green snake habitat. "Despite this, the snake is still found only in a handful of isolated areas in Lake County that contain remnant grassland habitat," he said. "The remaining populations may not be viable in the long-term due to small numbers and because habitat fragmentation, primarily due to roads and other physical barriers, makes re-colonization of restored sites improbable."

With little chance of natural recovery, LCFPD and the zoo established a partnership in 2010 to aid the recovery process through population supplementation, translocation, and reintroduction into suitable habitat.

The partnership's first challenge was to locate the snakes last summer – not an easy proposition with such a small population of tiny snakes that blend in so well with the grasses. But hard work paid off when a few adult snakes were located and brought to the zoo for breeding, and a large communal nest of more than 80 smooth green snake eggs was discovered in an undesirable location that is slated for development. The eggs were taken to the zoo for incubation and 83 neonates hatched in mid-summer 2010.

The biologists and animal care staff at the zoo are breaking new ground with the care and study of this species. Very little is known about it as there are no published accounts of any other accredited zoo ever caring for this species, and very few scientific studies related to the species. As such, the team is employing a number of different rearing and reintroduction techniques for the neonates to determine which methods garner the highest success rate.

On June 30, the first six zoo-raised smooth green snakes were released to the wild. Half were sent directly into the wild (so-called "hard release"), while half were released into pre-release enclosures within the preserve (so-called "soft release") where they will spend some time getting accustomed to being wild while still being contained in a controlled, managed environment designed to limit predators of the snake. Over the course of the summer about a dozen more snakes will be released – some of which will have very tiny radio transmitters affixed to them so the biologists are better able to track their movements and keep tabs on their survival success rates.

"We hope that this recovery program will not only restore a more robust population of this species in Illinois, but our work may also be a model for other organizations and regions seeking to help this species recover," said Sacerdote.



Chicago's Lincoln Park Zoo, a historic Chicago landmark founded in 1868, is dedicated to connecting people with nature by providing a free, family-oriented wildlife experience. A leader in conservation science both globally and locally, the zoo exemplifies the highest quality animal care and educational outreach. The not-for-profit zoo, managed by The Lincoln Park Zoological Society, is a member-supported organization and one of the nation's only free, privately managed zoos. For more information, call (312)742-2000 or visit www.lpzoo.org.


As Lake County's principal guardian of open space and natural areas since 1958, the Lake County Forest Preserves now manage more than 29,200 acres of land and offer innovative educational, recreational and cultural opportunities for all ages. Visitors of all ages can enjoy over 154 miles of trail for a variety of outdoor recreation uses, ponds and lakes for fishing, public golf courses, historical and cultural venues, public access to the Fox River, and award-winning nature and history education programs and events. Facilities of special interest include Independence Grove in Libertyville, Ryerson Conservation Area in Riverwoods, Lake County Discovery Museum in Wauconda, Greenbelt Cultural Center in Waukegan, and ThunderHawk Golf Club in Beach Park. For a program calendar or additional information about your Lake County Forest Preserves, visit LCFPD.org or call 847-367-6640 and request a free copy of the Horizons quarterly magazine.


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