Flock of American flamingos, Isabela Island, Galápagos Islands, Ecuador

American flamingos, Isabela Island, Galápagos Islands, Ecuador

The first thing you notice is the colour. A flock of American flamingos stands in the shallow water on Isabela Island, Galápagos Islands, and the water seems to borrow a hint of pink from their feathers. Those feathers were not always that colour. Flamingos hatch grey and gradually turn pink as pigments from algae and small crustaceans accumulate in their bodies.

The birds move slowly, with their heads upside down, sweeping their bills through the water to filter food such as brine shrimp and other tiny aquatic organisms. Every so often the flock shifts together, a reminder that flamingos are highly social birds that feed and rest in groups. When breeding season arrives, pairs build cone-shaped mud nests and lay a single egg above the waterline. Both parents incubate the egg and later feed the chick with a nutrient-rich crop secretion known as crop milk. The Galápagos population is relatively small, making these flocks an important part of the islands' wildlife.