His resignation touches off a national search for a new executive director, said Heather M. Bendit, spokeswoman for the zoo board of directors. There did not appear to be a front-runner.
"We greatly appreciate Bill's hard work on behalf of the zoo," said Cherifa Howarth, president of the board of directors. "We know his passion is wildlife conservation, and we wish him the best as he resumes that work in earnest."
Konstant said he had been tapped to work as a consultant for the private Margot Marsh Biodiversity Foundation and for another conservation foundation he would not name.
The Marsh foundation is based in the United States and focuses mainly on endangered primates; it has awarded $8 million in grants since the mid-1990s. The other foundation is overseas and focuses on saving everything "from plants to insects to whales," Konstant said.
"I'll be raising the funds that need to be raised and disseminated to get the greatest effect and make sure zoos are more directly involved in that effort," Konstant said.
Some of his future work could have local benefits. Last year, for example, the Margot Marsh foundation made a grant to help the Philadelphia Zoo with conservation of the golden lion tamarin, a small primate, in Brazil.
"I'm excited," Konstant said. "I have mixed feelings because my hope was that this was something I could do and still run a zoo, but that won't be possible, unfortunately."
Konstant is known for his work with the tiny, colorful frogs of Central America. He started an endangered-frog exhibit at the zoo, as well as one containing the critically endangered South American cotton-top tamarin. He also created a butterfly exhibit.
During his tenure, a green-roof pavilion for the public was added and money was found to double the zoo's parking to 240 spaces.
He plans to stay in Flourtown. "There will be opportunities for travel," Konstant said.
According to Howarth, "We expect to find a dynamic leader who will help us continue our mission of conservation through education."
The zoo has 300 animals, and showcases indigenous American species, such as the American bison, peregrine falcon, bald eagle, timber wolf, and American alligator. It is on Harding Boulevard in Norristown.
Contact staff writer Bonnie L. Cook at 610-313-8232 or firstname.lastname@example.org.