Fodor's Expert Review Reserva de la Biósfera Ría Celestún

Celestún is the point of entry to this 146,000-acre wildlife reserve with extensive mangrove forests and one of North America's largest flamingo colonies. Clouds of the pink birds soar above the estuary all year, but the best months for seeing them in abundance are November through March. This is also the fourth-largest wintering ground for ducks of the Gulf coastal region, and more than 365 other bird species make their home here, as do sea turtles. Mexican and American conservation programs protect the birds, as well as the endangered hawksbill and loggerhead marine tortoises, and species such as the blue crab and crocodile. Other endangered species that inhabit the area are the ocelot, the jaguar, and the spider monkey.

The park, which is set among rocks, islets, and white-sand beaches has several cenotes that are wonderful for swimming. The fishing is good here, too. Popular with Mexican vacationers, the park's sandy beach is pleasant during the morning but tends to get windy in the afternoon. And, unfortunately, mosquitoes gather in great numbers on the beach at dawn and dusk, particularly during winter months, making a walk on the beach uncomfortable. Area hotels generally drape their beds with mosquito netting, but bring along a good cream or spray to keep the bugs away.

Most Mérida tour operators run boat excursions of the ría (estuary) in the early morning or late afternoon, and it's not usually necessary to make a reservation in advance. Alternatively, you can hire a fishing boat at the entrance to town (they hang out under the bridge leading into Celestún). A 75-minute tour for up to six people costs about MX$1,200; a two-hour tour costs around MX$2,500. Although more expensive (MX$990 per person), local expert Alex specializes in ecotours and donates a portion of the proceeds to the Celestún Conservation Program (call Hotel Eco Paraíso to book).