The Isla Barro Colorado reserve is home for more than 400 species of birds, 225 ant species, and 122 mammal species, including collared peccaries, ocelots, coatis, and five kinds of monkeys. Its forest has 1,200 plant species—more than are found in all of Europe—ranging from delicate orchids to massive strangler fig trees.
In 1923 the island was declared a biological reserve and a tropical research station was built there; it is now the oldest such facility in the world. The island is administered by the Smithsonian Tropical Research Institute (STRI), which facilitates research by 200 or so visiting scientists and students per year and runs several weekly educational tours. Those tours are not only one of the most informative introductions to tropical ecology you can get in Panama, they are also excellent opportunities to see wildlife; after decades of living in a protected area full of scientists, the animals are hardly afraid of people.
Bring your passport, tour
receipt, bottled water, insect repellent, binoculars, and a poncho or raincoat (May through December). Wear long pants, hiking shoes, and socks to protect against chiggers. You should be in decent shape, since the tour includes several hours of hiking on trails that are steep in places and can be slippery; children under 10 are not allowed, students pay a discounted rate. You can reserve and pay for tours at the STRI website, or through one of the city's tour companies that specialize in nature tours; the tour companies will charge extra to book the STRI tour and provide transportation between your hotel and the dock in Gamboa.