Maria-faceira (Syrigma sibilatrix) The Whistling Heron is endemic to South America, where it occupies two disjunct regions. A northern population, which is smaller and paler, occurs in the llanos grasslands of Venezuela and eastern Colombia, whereas a larger, darker subspecies is widely distributed in the grasslands of southeastern South American, from the pantanal of Bolivia south to southeastern Brazil, Uruguay and northeastern Argentina. The Whistling Heron is one of the least aquatic members of its family and prefers to forage for large arthropods in open wet grasslands. This bird is named for its distinctive high pitched calls.
Large-billed Tern (Phaetusa simplex)
The Large-billed Tern is an unmistakable South American species, and the only member of the genus Phaetusa. The large, heavy bill and striking wing pattern with black primaries, white secondaries, and a gray back, make this bird visually distinctive. During the breeding season, this species can be found along broad, inland rivers and lakes, nesting on the sandy shores in mixed species colonies with Black Skimmers (Rynchops niger) and Yellow-billed Terns (Sternula superciliaris). During the nonbreeding season, some of the population congregates on the eastern coast of South America in coastal mangroves, beaches, and estuaries. Common throughout most of its range, the Large-billed Tern’s main threats are habitat disturbance and egg-collecting.
Limpkin (Aramus guarauna)
Apparently named for its shuffling gait, the Limpkin is an ibis-like bird about 65 cm tall. Its plumage is brown with white spots and streaks on the front half of the bird. The bill is pale and slightly decurved; the legs are long and dark, and the toes are long—allowing it to walk on floating vegetation. Limpkins occur from the extreme southeastern United States (Georgia and Florida), through the Greater Antilles and Mexico to Argentina. They inhabit many aquatic environments including flooded agricultural fields of rice and sugar cane, marshes, canals, wooded swamps, mangroves, flooded cypress forest, and lake and pond edges. As with the cranes (Gruidae) to which it is related, the Limpkin has a mechanical flight with a snappy upstroke that is recognizable at a great distance. They hide much of the day in tall vegetation and are seen and heard most frequently during late afternoon and at dusk. Their hollow, wailing, far-carrying call is well described by its Brazilian name Carão. A variety of wetland animals including fishes, reptiles and amphibians, insects, and mussels are taken as well as some plant material; however, large snails (Pomacea) are their main prey. During periods of drought, both the Limpkin and the snail are susceptible to population fluctuations. Movements, including the departure of females, may be migratory or in response to food or water availability. Depending on the habitat, nests may be placed in clumps of grasses, shrubs, or trees, often at some height (approx 7 m). [http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=142836].
Pied Lapwing (Vanellus cayanus)
This handsome black, white and buff species is sometimes called Pied Plover, perhaps a more appropriate name, given this species smaller size, plover-like shape, and behavior of running short distances and stopping abruptly. Typically fairly common to uncommon resident on sandbars and shorelines of ponds and rivers where sand and bare muddy areas are present. Movements are not well understood, but local and short distance movements are regular during the wet season when the species vacates flooded areas. Fairly quiet, Pied Lapwings are usually detected by scanning mudflats and shorelines. Occurs in Brazil, Guyana, Venezuela, Colômbia, Bolívia, Peru, Paraguai e Argentina. [Source: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=144436].
Rufescent Tiger-Heron (Tigrisoma lineatum)
Though diligent and quiet, observers may encounter this reclusive heron standing still along sluggish streams and backwater swamps. The Rufescent Tiger-Heron generally is the least-frequently encountered of the three species of Tigrisoma, and is considered uncommon to rare through much of its range. However, towards the southern end of its range, where it becomes the only Tiger-Heron present, they become more common and easier to see. Found in lowlands from southern Mexico south to northern Argentina, adult Rufescent Tiger-Herons are easily separated from the other species of tiger-heron by their rich rufous upperparts, especially the head and neck. Generally, immature tiger-herons are best left unidentified. With some practice, however, immature Rufescent Tiger-Herons may be identified by their more rufous head and neck. The shorter and stouter bill may also be a useful field mark, though this requires prior experience with all three species. Habitat is one of the best clues to identification; the species most similar to Rufescent, the Fasciated Tiger-Heron Tigrisoma fasciatum, usually is found on larger, faster-flowing streams and riverbanks, and primarily occurs at higher elevations.
Wattled Jacana (Jacana jacana)
The Wattled Jacana is distributed throughout the tropics and subtropics of South America and is common in just about any permanent and seasonally flooded freshwater wetlands. Floating vegetation is the limiting substrate for this species and will not occur in any wetland where this is absent. It uses its greatly elongated toes and claws to distribute its weight when walking on this notably submissive vegetation while foraging primarily for insects. The Wattled Jacana is highly polyandrous with females defending and breeding with 1-3+ males, which in turn each defend a small territory. Their nests are constructed to meet the needs of their floating habitat, and are often partially submerged.
A large and heavily-built, black duck of tropical rivers, ponds and marshes. This species is heavily hunted and very wary. Most often detected in early morning or late evening when seen flying to and from feeding areas. Diet includes a variety of grains, aquatic vegetation, fruits, nuts, small fish, insects, and crabs. Sometimes seen perched in trees. Males polygamous. Nests in tree cavities and nest boxes. In flight appears massive with broad wings and tail.
This handsome black, white and buff species is sometimes called Pied Plover, perhaps a more appropriate name, given this species smaller size, plover-like shape, and behavior of running short distances and stopping abruptly. Typically fairly common to uncommon resident on sandbars and shorelines of ponds and rivers where sand and bare muddy areas are present. Movements are not well understood, but local and short distance movements are regular during the wet season when the species vacates flooded areas. Fairly quiet, Pied Lapwings are usually detected by scanning mudflats and shorelines.
A small South American grebe, the White-tufted Grebe is the only grebe with a tuft of white feathers on its otherwise entirely black head. It breeds on mostly on small inland bodies of water such as marshy ponds, temporary pools, roadside ditches and slow floating rivers. Unlike many other grebes, the White-tufted Grebe feeds generally from the surface of the water and dives less often. During the nonbreeding season, large groups of White-tufted Grebes in the southern portion of their range will congregate and migrate up the South American coast, forming flocks in bays and other sheltered coastal waters. Generally common throughout its range, the White-tufted Grebe is the most frequently observed grebe in Argentina.
Mergulhão-pequeno (Tachybaptus dominicus). The tiny Least Grebe (24 cm length) is found in a variety of aquatic habitats including ponds, marshes, swamps, and lakes, typically with densely-vegetated margins. Pairs or family groups are usually encountered but outside the breeding season they often form flocks of 20 or more. Least Grebe breeds from south Texas and western Mexico through the Greater Antilles to central Argentina. Where suitable habitat may not be available every year, or in response to especially cold weather, (south Texas and northern Tamaulipas, for example), the bird’s range is subject to short-term expansions and contractions. Such movements may account for extralimital occurrences; i.e., California and Arizona. Food items include vegetation, many kinds of small fishes, crustaceans, and insects that are taken during dives, snatched from the air, or picked off the water’s surface or the stems of aquatic plants. Its small size, lead gray plumage, yellow eye, white wing patches, and slender, dark bill help differentiate it from other small grebes and ducks. In non-breeding plumage, note the adult’s white chin.