Оңтүстік Америка құсы – Чиви виреосы

Species of bird from South America

The chivi vireo (Vireo chivi) is a small South American songbird in the family Vireonidae. It was formerly considered a subspecies of the red eyed vireo. It is usually green to yellow green in color with off white underparts, and a gray crown. It has a whitish supercilium extending over its ear coverts, and its lores are dull gray in color. The chivi vireo has nine subspecies. It is found throughout most of northern, eastern and central South America, only being absent from southern Chile and southern Argentina. It inhabits multiple types of habitat across its range, and appears to adjust well to slightly disturbed habitat. The chivi vireo is mainly resident, but at least two of the subspecies inhabiting the south of its range are known to be migratory. The chivi vireo mates from May to June or October to January, depending on the region and subspecies. It makes cup nests and lay eggs in clutches of 2–4 which are incubated by the female, taking 10–16 days to hatch. Nestlings take 10–13 days to fully develop. The majority of the bird's diet is composed of arthropods, although some subspecies eat fruit and some are also thought to be nectarivorous.

The chivi vireo was described by the French ornithologist Louis Pierre Vieillot in 1817 and given the binomial name Sylvia chivi. The specific epithet is an onomatopoeia for its song, which Vieillot rendered as "chivi chivi". Vieillot based his description on that for the "Gaviero" by the Spaniard Félix de Azara that had been published in 1802. Ornithologists previously treated the chivi vireo as a subspecies of the red eyed vireo (Vireo olivaceus), but unlike the red eyed vireo that migrates to North America, the chivi vireo remains in South America to breed and does not migrate. Based on a molecular phylogenetic study published in 2017 that found significant genetic differences and little introgression, the chivi vireo was promoted to species status.

The species looks similar to the related red eyed vireo and yellow green vireo. It is in length, with the mass and length of the bill and wings varying in different subspecies.

The species is largely resident throughout its range, but in the south of its range, the subspecies chivi and diversus are known to be migratory. There are also some subspecies that are likely to undertake short migrations.

The species is primarily an insectivore, but some populations are known to consume fruit, and they may be important seed dispersers for some plants. It mainly consumes arthropods, especially caterpillars and other insect larva. They have been recorded consuming fruits of Myrsine coriacea, Rapanea lancifolia, Myrsine ferruginea, Trichilia spp., Cabralea canjerana, Talauma ovata, Davilla rugosa, Nectandra megapotamica, Byrsonima sericea , Miconia minutiflora, Cupania emarginata and oblongifolia, Zanthoxylum rhoifolium, Trema micrantha, Alchornea glandulosa, and Pera glabrata. It is thought to be an important seed disperser for Cabralea canjerana. It is also suspected of being nectarivorous.

The species nests in the austral spring in the south of its range, and in the middle of the year in the north. The populations in Venezuela, Tobago, and Colombia nest in May–June, while the populations of the nominate subspecies in Peru have been seen nesting in November. Brazilian populations are thought to nest in October–January. Nests of vividior are generally built in a cup shape out of grass, vegetable fibers, and small amounts of plant down in a tree fork, while nests of griseobarbatus are cup shaped structures built out of dry weeds, vines, and bark and lined with black lichen, feathers, and seed down. The nests of griseobarbatus had an external height and depth of 50 mm and 77 mm, with an internal height and depth of 31 mm and 52 mm. Eggs are laid in clutches of 2–4 at a time. Eggs vary in appearance and size between different subspecies. The mean size of eggs in griseobarbatus is reported to be , while that size of eggs in Brazil is , and the size of eggs in Argentina being The average mass of eggs measured in southeastern Brazil was
Eggs of vividior are white with some blackish spots on the larger end of the egg. Eggs of griseobarbatus are said to be white with sparse and faint markings. Eggs in eastern Brazil have been described as white. The eggs in northeastern Argentina have been described as being white and having gray or fine chestnut markings and dark lines which were concentrated at the larger end. The incubation period of the eggs is reported as being 10–16 days. Only females incubate the eggs. The nests are probably parasitized by shiny cowbirds. Eggs might also be eaten by snakes as one nest in Ecuador was observed being predated on by a snake. The nestling period is 10–13 days, and young are dependent on parents for a while after they have fledged.

The chivi vireo is listed as a least concern species by the IUCN. The species is common across its large range, and seems to have a stable population. The population may also be increasing locally. Also, its acceptance of disturbed habitat increases its chances of survival.