The mountains of the Sierra Madre Occidental surround Puerto Vallarta and the Bahia de Banderas, the wide bay that was once a haven for pirates and Spanish explorers and now is a port of call for cruise ships. The hillside jungle surrounding the resort community is home to more than 400 species of birds and 300 varieties of orchids, as well as other abundant tropical flora and fauna. Visitors can get a bird's-eye view of Puerto Vallarta's exotic land on a canopy tour, but be prepared to meet certain age, weight and health . . .