While a group of flamingos remains in Río Lagartos year-round, you’ll see the highest concentration April, June, and July. From November to March, the young are just beginning to color. At hatching, flamingos are mostly white, and at three months the black feathers along their wings begin to grow.

The locals and government are both very protective of the flamingos. During the April–June brooding season, visitors are not allowed to approach the nesting area, as the skittish birds sometimes knock their eggs out of their nests (they lay only one per year). During this time, however, the feeding area can still be visited.

Río Lagartos Expeditions (Restaurante Isla Contoy, Calle 19 No. 134, tel. 986/862-0000, www.riolagartosexpeditions.com) is the most experienced and recommended tour operator. Be aware that freelancers will flag you down on the street entering town, offering tours, even saying Río Lagartos Expeditions has closed—don’t believe them.

Trips take 2–2.5 hours and cost US$56 for 1–6 people, plus a US$2 per person natural reserve fee. If you call ahead, guides will usually merge smaller groups to save you money. Tours are offered 6 a.m.–7 p.m. daily, and the earlier you go the better.

Although you can see the flamingos all day, it takes almost 45 minutes to get to the flamingo sites and leaving early means seeing other water birds along the way. The water is also calmer in the morning.

It is best to arrange your trip the day before; English- and Italian-speaking guides typically are available. Binoculars aren’t absolutely necessary but nice to have; bring your own or ask to borrow a pair.