Southern Beardless-Tyrannulet

Camptostoma obsoletum

Small flycatcher, common and widespread from Costa Rica to Argentina. Plumage is nondescript (and quite variable across range), but note bushy crest, active behavior, short bill, and plain face. Singles, pairs, or small groups can be found in a variety of wooded habitats, from dry scrub to the edge of mature rainforest, but often prefers second growth. Voice varies across range, with different populations probably representing separate species. Northern birds give plaintive whistled “teew, teew, teew” notes. Southern birds can give much different descending sputtering trill in addition to plaintive whistles.

识别特征

The southern beardless tyrannulet is 10.2 cm (4.0 in) long, weighs 7.5 g (0.26 oz) and often resembles a tiny yellow-bellied elaenia. The head is dark brown or grey with an erectile crest and pale supercilium. The upperparts are grey-green becoming paler on the rump. The wings are brown with yellow feather-edging and two whitish, yellowish or cinnamon wing bars. The tail, which regularly is held cocked, is brown, the throat grey, the breast yellowish, and the abdomen yellow. The bill is black, but at least the base of the lower mandible is pale.<p>Subspecies from humid regions (e.g. the Amazon basin) are generally greener with pure yellow bellies, while subspecies of drier regions (e.g. eastern Brazil and western Ecuador) generally are greyer with duller bellies. The subspecies C. o. venezuelae occurs only in Trinidad and Venezuela, and is well distinct in plumage tone.<p>The call is a loud whistled TLEEE-tee-tee-tee. In courtship, the crests are raised, the tail flicked, and an excited mixture of the TLEE call and a churring pee-chrrr-pee-chrrr is given.<p>Sexes are similar, and this species always appears brighter, especially with regard to the wing bars, than the closely related northern beardless tyrannulet (C. imberbe), with which it was once considered conspecific. However, the two forms overlap without interbreeding in central Costa Rica.

分类信息

学名
Camptostoma obsoletum
命名信息
(Temminck, 1824)
Passeriformes
Tyrannidae
Camptostoma

分布与栖息地

迁徙
Resident species

行为

This species is found in light forests, cultivation, gardens with trees and dry cerrado savanna. Southern beardless tyrannulets are active birds, feeding in a vireo- or warbler-like fashion on insects, spiders and berries. Animal prey is either picked out of the air or off plants with a dedicated sally flight, or gleaned from vegetation. Fruit, e.g. from Alchornea glandulosa, are typically picked off when perched or during hovering flight. This species will readily mob small predators like the ferruginous pygmy owl (Glaucidium brasilianum). It tends to keep on its own except during the breeding season, and rarely joins mixed-species feeding flocks.<p>The domed nest is made of plant fibre or leaves with a side entrance. The nest is placed by a tree fork, usually near a wasp nest, which presumably provides some protection from predators. The typical clutch is two white eggs, which are marked with rufous and lilac mostly at the larger end. Incubation by the female is 14–15 days to hatching, with another 17 days to fledging.<p>As it ranges so widely, this bird is considered a species of least concern by the IUCN.

保护状况

种群趋势
stable

照片

分布

鸟叫声

开始您的观鸟之旅

在户外识别鸟类,并在下一次观察时随手查阅鸟类图鉴。