Waders, gulls and terns | Charadriiformes

Famílias desta ordem

• Thick-knees and stone-curlews | Burhinidae3 espéciesLarge yellow eyes and a short, heavy bill with a swollen tip: these are birds of dusk and darkness that spend the day motionless on the ground, where their sandy, streaked plumage makes them hard to separate from the soil. The legs are long, with a conspicuously thickened joint halfway down that gives the group its name, and carry three short, thick toes with no hind toe. They live on dry, stony or sandy open country, often far from water, taking beetles, worms, lizards and mice on foot. The nest is a scrape with two eggs, and as evening falls a far-carrying, wailing call gives them away.
• Stilts and avocets | Recurvirostridae3 espéciesExceptionally long legs and a thin, flexible bill, either straight or curved upwards: waders that walk belly-deep into shallow, often brackish or saline water. The front toes are webbed, so they can also feed while swimming; one build picks prey one at a time from the surface, the other sweeps the half-opened bill sideways through the water and feels what passes between the mandibles. In every species the plumage is a crisp pattern of black and white that changes little between summer and winter. They breed in loose colonies on bare ground beside water, lay three or four eggs in a scrape, and drive intruders off with loud calls and diving attacks.
• Oystercatchers | Haematopodidae2 espéciesA long, heavy, laterally flattened orange-red bill is the tool of this family: it is driven like a chisel between the shells of a bivalve or used like a hammer on the shell itself, and it wears down so fast in the work that it grows continuously. With it go short, sturdy legs with three toes, a coloured eye-ring, and a plumage that is either black and white or wholly black, alike in both sexes. Unlike almost all other waders, the chicks do not feed themselves: opening shellfish takes so much practice that the parents go on feeding them for months. The clutch is two or three eggs in a scrape, and the birds announce themselves in loud, piercing piping displays, small groups walking about with the neck drawn in and the bill pointed down.
• Plovers and lapwings | Charadriidae16 espéciesEighteen species in eight genera occur in this guide. Compact birds with a large head, short neck and a short bill thickened towards the tip, made for picking prey from the surface rather than probing into the ground. They feed with a characteristic run, stop and peck pattern, also in the dark, and some species patter one foot on wet ground to bring prey to the surface. Black bands across breast and head break up the outline on bare ground. The clutch usually consists of three or four pear-shaped eggs in a scrape on bare sand, gravel or short-grazed grassland; when danger threatens the parents lead an intruder away with a feigned broken wing. Some species are resident here: the Andean Lapwing on wet grassland and marshes of páramo and puna, the Diademed Sandpiper-Plover in high Andean bogs, the plovers of the sandy beaches and salt flats along the Pacific coast, the Pied Lapwing on sandbars along the rivers of the Amazonian lowlands, and the Southern Lapwing, which carries a sharp spur at the bend of the wing and noisily attacks anyone who approaches its nest. Others are migrants from the far north that winter here or pass through, with long, pointed wings for the flight from the tundra.
• Seedsnipes | Thinocoridae3 espéciesThree of the family's four species occur in this guide, in two genera: the Rufous-bellied Seedsnipe on rocky slopes and in cushion bogs high in the Andes, often just below the snowline, the Grey-breasted Seedsnipe in the grasslands and peat bogs of the puna, and the Least Seedsnipe, which besides the high plateau also lives in the coastal desert of Peru and the dry southwest of Ecuador. Seedsnipes are relatives of the waders that, with their compact body, short legs and short, conical bill, look like a partridge or quail. Unlike almost all other waders they are vegetarian: they eat buds, leaves and seeds and obtain much of their water from that food. The nostrils are covered by a horny flap. The plumage is a finely scaled pattern of brown, grey and black that is hard to see on the ground; when threatened they crouch and only fly up at the last moment, with a fast, zigzag flight and a grating call. The nest is a scrape in the ground, usually with four eggs, which the bird may cover with soil when it leaves the nest.
• Jacanas | Jacanidae2 espéciesA small family of eight species in tropical freshwater marshes worldwide. In this region Wattled Jacana is widespread in lowland marshes: east of the Andes in the Amazonian foothills, in the Caribbean lowlands of Colombia and, on the Pacific side, in western Ecuador and north-western Peru; Northern Jacana of Central America occurs only as a vagrant. Their best-known feature is the extremely long toes and claws, which spread their weight over a large area so that they can walk on water lilies, water hyacinth and other floating vegetation. Both species have a fleshy frontal shield, red with wattles in Wattled Jacana and yellow in Northern Jacana, a sharp spur at the bend of the wing and yellow-green flight feathers that show only in flight. The flight is short and fluttering, with dangling legs. They eat insects, snails and other invertebrates picked from leaves or from under turned-up leaf edges. Sex roles are reversed. The female is clearly larger than the male, defends a territory holding several males, and lays a clutch for each of them. The male alone incubates the four glossy, black-scrawled eggs on a floating nest and alone cares for the chicks, which he takes under his wings when danger threatens. The calls are rasping, cackling and chattering. Their closest relatives are the painted-snipes.
• Sandpipers and allies | Scolopacidae42 espéciesThe bill is not only long and sensitive but mobile: the tip of the upper mandible alone can be raised, so the bird can seize a worm deep in the mud without opening the bill along its whole length. Length and curvature differ greatly from species to species, so that birds feeding side by side on the same flat reach different depths and different prey. Forty-two species in ten genera occur in this guide; most are migrants from North America that winter along the Pacific coast, on riverbanks and at the lakes of the high Andes, while the snipes (Gallinago) also breed here in boggy parts of the páramo and puna. The plumage is grey-brown and finely marked, and changes completely twice a year: a conspicuous breeding dress and a plain winter one. Four pear-shaped eggs in a scrape, chicks that find their own food from the first day, and outside the breeding season large flocks that wheel as one over the tidal flats.
• Jaegers and skuas | Stercorariidae5 espéciesGull-like in shape, but with a heavier chest, a strongly hooked bill made up of separate horny plates with a fleshy cere over the base, and sharp, curved claws on webbed feet; females are larger than males. The plumage is brown or grey-brown, in several species with a pale and a dark morph side by side, and a white patch at the base of the primaries flashes in flight. They live largely on what other seabirds catch, forcing gulls and terns in long chases to give up their prey, and they also take eggs, chicks and carrion. The five species in this guide breed elsewhere, three on the Arctic tundra and two on the coasts of southern South America and Antarctica, where they lay two eggs in a scrape and defend it with diving attacks; here they are visitors to the fish-rich waters of the Humboldt Current off the west coast.
• Skimmers, noddies, terns and gulls | Laridae42 espéciesWebbed front toes and a small, raised hind toe: these birds can rest on the water, and salt glands above the eyes let them drink sea water as well. Forty-three species in seventeen genera occur in this guide, among them some remarkable ones: the Andean Gull breeds by lakes high in the Andes, the Inca Tern lives along the cold Humboldt Current, the Lava Gull is found only on the Galápagos and the Galápagos Swallow-tailed Gull is the only gull that hunts at sea by night, while Black Skimmer, Large-billed Tern and Yellow-billed Tern fish along the great lowland rivers. Two builds stand side by side within the family: heavier birds with a stout, slightly hooked bill that will eat almost anything they can get hold of, and slighter birds with a thin, pointed bill held downwards while hovering, before they drop into the water. They nest almost always in ground colonies, with one to three blotched eggs; the downy chicks stay at the nest and are fed by both parents, unlike the self-feeding young of the waders. Most species moult twice a year and show a different head pattern in winter, and in the largest species it takes two to four years before the adult plumage is complete.
• Painted-snipes | Rostratulidae1 espécieA small family of three marsh birds with a long, slightly decurved bill, related to the waders. Only the South American Painted-snipe (Nycticryphes semicollaris) is recorded in this area, as a rare visitor in eastern Bolivia; its breeding range lies in Paraguay, southeastern Brazil, Argentina and Chile. It lives hidden in dense marsh grass and shows itself mainly at dusk. In painted-snipes the roles are reversed: the female is larger and more boldly marked and courts the male, while the male incubates and tends the young.