The vireos make up a family, Vireonidae, of small to medium-sized passerine birds found in the New World (Canada to Argentina, including Bermuda and the West Indies) and Southeast Asia. The family contains 62 species and is divided into eight genera. "Vireo" is a Latin word referring to a green migratory bird, perhaps the female golden oriole, possibly the European greenfinch.

They are typically dull-plumaged and greenish in color, the smaller species resembling wood warblers apart from their heavier bills. They range in size from the Chocó vireo, dwarf vireo and lesser greenlet, all at around 10 cm and 8g, to the peppershrikes and shrike-vireos at up to 17 cm and 40g.

Distribution and habitat

Most species are found in Middle America and northern South America. Thirteen species of true vireos occur farther north, in the United States, Bermuda and Canada; of these all but Hutton's vireo are migratory. Members of the family seldom fly long distances except in migration. They inhabit forest environments, with different species preferring forest canopies, undergrowth, or mangrove swamps.

Behaviour

The resident species occur in pairs or family groups that maintain territories all year (except Hutton's vireo, which joins mixed feeding flocks). Most of the migrants defend winter territories against conspecifics. The exceptions are the complex comprising the red-eyed vireo, the yellow-green vireo, the black-whiskered vireo, and the Yucatan vireo,<!--if I understand Salaman and Barlow correctly--> which winter in small wandering flocks.

Traditionally the family was considered to include four New World genera containing the true vireos (Vireo), the greenlets (Hylophilus), the shrike-vireos (Vireolanius) and the peppershrikes (Cyclarhis). However, phylogenetic studies found Hylophilus to be polyphyletic, with the greenlets split into three distinct groups: the "scrub" greenlets in a restricted Hylophilus, the "canopy" greenlets in resurrected genus Pachysylvia and the tawny-crowned greenlet in new genus Tunchiornis.

In addition, biochemical studies have identified two babbler genera (Pteruthius and Erpornis) which may be Old World members of this family. Observers have commented on the vireo-like behaviour of the Pteruthius shrike-babblers, but apparently no-one suspected the biogeographically unlikely possibility of vireo relatives in Asia. Some recent taxonomic treatements, such as the IOC taxonomy followed here, include Pteruthius and Erpornis in Vireionidae,

Species in taxonomic order

{| class="wikitable"

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! Image !! Genus !! Species

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|175px ||Pteruthius - shrike-babblers ||

  • White-bellied erpornis or white-bellied "yuhina", Erpornis zantholeuca

|-

|175px ||Cyclarhis , the peppershrikes ||

  • Rufous-browed peppershrike, Cyclarhis gujanensis
  • Black-billed peppershrike Cyclarhis nigrirostris

|-

|175px ||Vireolanius , the shrike-vireos ||

  • Chestnut-sided shrike-vireo, Vireolanius melitophrys
  • Green shrike-vireo, Vireolanius pulchellus
  • Yellow-browed shrike-vireo, Vireolanius eximius
  • Slaty-capped shrike-vireo, Vireolanius leucotis

|-

|175px ||Hylophilus ||

  • Grey-eyed greenlet, Hylophilus amaurocephalus
  • Rufous-crowned greenlet, Hylophilus poicilotis
  • Olivaceous greenlet, Hylophilus olivaceus
  • Ashy-headed greenlet, Hylophilus pectoralis
  • Brown-headed greenlet, Hylophilus brunneiceps
  • Lemon-chested greenlet, Hylophilus thoracicus
  • Scrub greenlet, Hylophilus flavipes
  • Grey-chested greenlet, Hylophilus semicinereus

|-

|175px ||Tunchiornis ||

  • Tawny-crowned greenlet, Tunchiornis ochraceiceps

|-

|175px||Pachysylvia ||

  • Lesser greenlet, Pachysylvia decurtata
  • Dusky-capped greenlet, Pachysylvia hypoxantha
  • Buff-cheeked greenlet, Pachysylvia muscicapina
  • Golden-fronted greenlet, Pachysylvia aurantiifrons
  • Rufous-naped greenlet, Pachysylvia semibrunnea

|-

|175px ||Vireo , the true vireos. ||

  • The "hypochryseus" group
  • Golden vireo, Vireo hypochryseus
  • The "olivaceous" group.
  • Yellow-green vireo, Vireo flavoviridis (sometimes included in V. olivaceus)
  • Red-eyed vireo, Vireo olivaceus
  • Yucatan vireo, Vireo magister
  • Black-whiskered vireo, Vireo altiloquus
  • Chivi vireo, Vireo chivi
  • Noronha vireo, Vireo gracilirostris
  • The "gilvus" group.
  • Tepui vireo, Vireo sclateri
  • Philadelphia vireo, Vireo philadelphicus
  • Warbling vireo, Vireo gilvus
  • Brown-capped vireo, Vireo leucophrys
  • The "eye-ringed" group.
  • Hutton's vireo, Vireo huttoni
  • Gray vireo, Vireo vicinior
  • Yellow-throated vireo, Vireo flavifrons
  • Yellow-winged vireo, Vireo carmioli
  • Choco vireo, Vireo masteri
  • Blue-headed vireo, Vireo solitarius
  • Cassin's vireo, Vireo cassinii
  • Plumbeous vireo, Vireo plumbeus
  • Blue Mountain vireo, Vireo osburni
  • Flat-billed vireo, Vireo nanus
  • Mangrove vireo, Vireo pallens
  • Providencia vireo, Vireo approximans
  • Cozumel vireo, Vireo bairdi
  • San Andres vireo, Vireo caribaeus
  • White-eyed vireo, Vireo griseus
  • Thick-billed vireo, Vireo crassirostris
  • Jamaican vireo, Vireo modestus
  • Cuban vireo, Vireo gundlachii
  • Bell's vireo, Vireo bellii
  • Puerto Rican vireo, Vireo latimeri
  • Black-capped vireo, Vireo atricapilla
  • Dwarf vireo, Vireo nelsoni
  • Slaty vireo, Vireo brevipennis

|-

|}

References

<!-- Bird Conservation International (2007) 17:45–61. doi: 10.1017/S0959270906000554 -->

  • Vireos (Vireonidae) information, including 33 species with videos and 40 with photographs at the Internet Bird Collection