Оңқайлық қасқырқұс: Америка тропиктерінің сирек құсы

Species of bittern like bird

The sunbittern (Eurypyga helias) is a bittern like bird of tropical regions of the Americas, and the sole member of the family Eurypygidae (sometimes spelled Eurypigidae) and genus Eurypyga. It is found in Central and South America, and has three subspecies. The sunbittern shows both morphological and molecular similarities with the kagu (Rhynochetos jubatus) of New Caledonia, indicating a gondwanic origin, both species being placed in the clade Eurypygiformes.

The sunbittern is usually placed in the Gruiformes, but this was always considered preliminary. Altogether, the bird is most similar to another bird that was provisionally placed in the Gruiformes, the kagu (Rhynochetos jubatus). Molecular studies seem to confirm that the kagu and sunbittern are each other's closest living relatives and have a similar wing display. They are probably not Gruiformes (though the proposed Metaves are just as weakly supported). Altogether, the two species seem to form a minor Gondwanan lineage which could also include the extinct adzebills and/or the mesites, and is of unclear relation to the Gruiformes proper. Notably, the kagu and mesites also have powder down.

The sunbittern was formerly treated as two species (E. helias and E. major), but now they are treated as a single species with considerable variation between the subspecies. The three subspecies are recognised on the basis of plumage characters and size. The three subspecies are allopatric. The species is found in the humid Neotropical forests, generally with an open understorey and near rivers, streams, ponds or lagoons.

Sunbitterns start nesting in the early wet season and before it starts they make flight displays high in the forest canopy. They build open nests in trees, and lay two eggs with blotched markings. The young are precocial, but remain in the nest for several weeks after hatching.