Comprises medium to conspicuously large waterbirds, with total body lengths ranging from 33 to 59 cm and body masses spanning from 400 g in smaller forms to well over 2.5 kg in exceptionally bulky species like Fulica gigantea. They exhibit a compact, hydrodynamically compressed body plan encased in thick, waterproof plumage dominated by uniform slate-black or dark sooty gray tones, occasionally disrupted by white undertail coverts or fine white borders along the secondaries. The most prominent morphological hallmark is the unfeathered frontal shield, an expanded, calloused integumentary structure positioned directly above the culmen on the forehead, showcasing clear diagnostic colors such as ivory white, canary yellow, or intense carmine red depending on the specific lineage. The bill is strong, laterally flattened, and acutely tapered for snipping tough marsh plants. The legs feature muscular tarsi and exceptionally elongated toes lacking broad interdigital webbing, possessing instead wide scalloped lateral lobes along each phalanx that spread mechanically on the backward stroke to provide exceptional propulsion across open waters and mudflats.

Geographical distribution: Maintains a cosmopolitan distribution across the globe, persisting in nearly all non-polar continental zones. It reaches an exceptional peak of evolutionary diversification within South America, notably throughout the Andes Mountains and the vast plains of the Southern Cone, where high-elevation and lowland specialists thrive sympatrically. Representatives also inhabit extensive territories across Eurasia, sub-Saharan Africa, the Australasian region, and broad swaths of North America, easily colonizing environments ranging from coastal lowlands to highland lacustrine plateaus situated above 4,000 meters above sea level.

Habitat: Shows a pronounced affinity for lentic wetlands characterized by quiet, shallow to moderately deep waters and a healthy matrix of emergent and submerged flora. Typical environments include eutrophic lakes, high-altitude Andean tarns, fresh-water marshes, brackish coastal lagoons, protected river deltas, and man-made reservoirs. The presence of dense belts of vegetation comprising reeds and bulrushes from genera like Typha, Schoenoplectus, and Juncus is indispensable, as these vegetative complexes furnish critical cover against avian predators, supply nesting substrate, and foster abundant aquatic foraging grounds.

Feeding: Adopts an opportunistic, predominantly herbivorous dietary strategy, grazing heavily upon submerged macrophytic vegetation, tender green shoots, rhizomes, aquatic filamentous algae, and seeds of species from genera such as Potamogeton, Elodea, Myriophyllum, and Chara. This plant matter is frequently augmented with essential animal protein scavenged or captured from the water column, including aquatic macroinvertebrates, hemipterans, coleopterans, freshwater snails, tiny crustaceans, and occasionally stray tadpoles or small fish caught via surface up-ending or short underwater dives.

Behavior: Displays marked behavioral plasticity across the seasons; during the post-breeding cycle, it often gathers in expansive, highly gregarious flocks that number in the tens of thousands across critical flyway staging grounds, whereas the arrival of the reproductive cycle sparks extreme intraspecific territoriality. Defending territorial borders entails striking behavioral postures such as low-profile arching of the neck, direct exhibition of the frontal shield, and violent confrontations where rival birds sit upright on the water, lashing out with their clawed, lobed feet and thrashing their wings in noisy water sprays. Takeoff from open water is energetically costly, demanding an extended running sprint across the surface accompanied by vigorous foot-slapping before achieving sustained aerodynamic flight.

Nesting: Nesting protocols center around the assembly of large, floating or semi-floating vegetative platforms anchored firmly to robust emergent stems of reeds or rushes. In remarkable instances within high-altitude environments, such as that seen in the horned coot (Fulica cornuta), pairs drag tons of loose rocks into shallow water to build immense stone cairns that isolate the nest cup from terrestrial predators. Clutches usually consist of 4 to 12 eggs bearing a stone-buff ground color intricately speckled with reddish-brown and dark charcoal spots. Both parents share incubation duties equally across a period lasting 21 to 26 days. The hatchlings are semiprecocial and nidifugous, leaving the rim of the nest within a couple of days; they are covered in dense blackish down and sport startlingly bright vermilion red, orange, or golden filamentous skin structures around the crown and bill that trigger prompt parental provisioning.

Conservation status: The broader, widespread continental populations are categorially assessed as Least Concern (LC) under the internationally recognized standards established by the International Union for Conservation of Nature (IUCN), supported by extensive geographical distributions and robust individual numbers. However, insular forms and narrowly endemic lacustrine taxa, including Fulica alai in the Hawaiian chain or Fulica cornuta in high-Andean peatlands, face pressing survival challenges that position them in Vulnerable (VU) or Near Threatened (NT) categories, primarily driven by wetland reclamation, water redirection for agriculture, industrial mining, and the overall degradation of fragile aquatic ecosystems.