Gannets and cormorants | Suliformes

Families in this order

• Frigatebirds | Fregatidae2 speciesA family of five tropical seabirds, two of which occur in Mexico and Central America. Magnificent Frigatebird is common along both coasts and breeds in colonies on islands and in mangroves, for instance on Isla Isabel off Nayarit; Great Frigatebird breeds on remote Pacific islands such as Cocos Island and is scarce elsewhere. Frigatebirds have the largest wing area relative to body weight of any bird: long, narrow, angled wings and a deeply forked tail. On rising air they climb high and glide over long distances, sometimes for weeks without landing. The plumage is not waterproof and the legs are short and weak, so they cannot swim or take off from the water. They snatch flying fish and squid from the surface in flight and chase boobies, terns and gulls until these drop their catch. In the colony males inflate a bright red throat pouch and quiver their spread wings to attract females flying over. The single chick fledges only after five or six months and is then fed by the parents for a long time, so that many birds breed only every other year.
• Boobies and gannets | Sulidae7 speciesLarge seabirds with a cigar-shaped body, long pointed wings and a wedge-shaped tail; the heavy conical bill has no hook, but its finely serrated cutting edges hold a slippery fish. The eyes are set well forward and give the depth judgement the plunge dive demands: from ten to thirty metres up the bird falls into the sea with its wings swept back, air sacs under the skin of head, neck and breast absorbing the impact. Over the cold upwelling along the west coast they hunt shoals of sardine and anchovy in dense swarms, alongside seals, dolphins and shearwaters. The gannet breeds in colonies of tens of thousands of pairs on a handful of rock islands and guano platforms, one egg a year on a raised mound of droppings and seaweed, while the boobies of the genus Sula nest more loosely and in smaller numbers in the tropical waters off the eastern coasts and islands. The chick hatches black and naked and needs three to four years to reach adult plumage.
• Anhinga and darters | Anhingidae1 speciesA small family of four species of tropical and subtropical fresh waters. In Mexico and Central America only the Anhinga occurs, in the lowlands along both coasts, in marshes, rivers, lagoons and mangroves. It resembles a cormorant with a slimmer body, a long, fan-shaped tail and a very long, thin neck; the male is black with silvery-white markings on the wings, the female has a pale brown head, neck and breast. A special hinge between the eighth and ninth neck vertebrae lets the bent neck shoot forward like a spring, and with its straight, dagger-sharp bill the bird spears a fish underwater, then shakes it free at the surface, tosses it and swallows it head first. It often swims low in the water, with only the snaking head and neck showing. Because the feathers let water in, after hunting it must sit on a branch for a long time with wings spread to dry and warm up. In flight it alternates flapping with gliding, and on thermals it circles high like a small raptor. Anhingas nest in trees over water, often among cormorants and herons.
• Cormorants and shags | Phalacrocoracidae4 speciesLong-bodied dark waterbirds with a long neck and a bill sharply hooked at the tip: the fish is gripped, not speared. They dive from the surface and swim under water with both feet at once; the legs are set far back, which makes walking laboured, and the stiff wedge of a tail works as a rudder. The plumage lets itself be partly soaked, which cuts buoyancy but obliges the bird to dry off after fishing with its wings half spread — the posture the whole family is known by. The nest of sticks or weed stands in a colony on rock, in trees or in reedbeds; three or four pale blue eggs under a chalky coating, and naked young that put on black down within days.