Vireo-averla dai fianchi castani

Identificazione

One of the largest species in Vireonidae, with a length of 16.5 to 18 cm (6.5 to 7.1 in) and a mean body mass of 34.7 g (1.22 oz). Sexes are of similar sizes. Only one other population of Vireonid reaches this size - the Cozumel rufous-browed peppershrike Cyclarhis gujanensis insularis.<p>A striking bird, adult chestnut-sided shrike-vireos have bright green backs and largely white undersides punctuated by their eponymous chestnut flanks that meet in a chest band. The head is characterized by a slate crown and nape, golden-yellow eyebrows that sometimes reach the lores at the bill base, black eyelines that are thin near the bill and thickest where they meet the gray nape, white cheeks, thin black malars, and a white throat. The legs are pink, and irides are yellow. Chestnut-sided shrike vireos are sexually dimorphic, unlike most species of Vireonid which are monomorphic (with the exception of the black-capped vireo Vireo atricapillus). Females can be separated from the males by their paler plumage and reduced chestnut coloration.<p>The song is a complex, multi-pitched single-syllable whistle that quickly ascends in pitch with multiple harmonics before a longer, less harmonized descent, often given in repeated succession with pauses between whistles generally lasting between 0.7–1 seconds. Calls consist of a hoarse chatter, similar to many other species of Vireonid. A relatively difficult to observe species, vocalizations have proven to be one of the best ways to detect chestnut-sided shrike-vireos, with songs audible up to 400 metres (1,300 ft) away.<p>Six primary vocalizations have been described by Barlow &amp; James:

Tassonomia

One of four species within the genus Vireolanius. The exact relationships of Vireolanius to other members of Vireonidae are not fully resolved, but it appears to be one of the basal groups within the New World Vireonidae along with Cyclarhis possibly Hylophilus. Within the genus Vireolanius, the chestnut-sided shrike-vireo appears to be the outgroup with respect to all other shrike-vireos.<p>Two or three subspecies are recognized, depending on the taxonomic list being used. The type specimen of V. m. goldmani is alleged to be an immature of V. m. melitophrys, in which case it should be considered a junior synonym of V. m. melitophrys.

Nome scientifico

Vireolanius melitophrys

Autorità

Bonaparte, 1850

Ordine

Passeriformi

Famiglia

Vireonidi

Genere

Vireolanius

Areale e habitat

A humid pine-oak specialist, this species is restricted to montane habitats from central Mexico (Jalisco and San Luis Potosí) to southern Guatemala. It is nowhere common, having one of the lowest relative abundances of any medium-sized songbird in Oaxacan pine-oak forests. In all regions, it is confined to tropical and subtropical forests zones, mostly above 1,800 metres (5,900 ft). In San Luis Potosí, this species is found principally between 4,000 feet (1,200 m) to 6,700 feet (2,000 m) in elevation. Similarly, a study in Jalisco only recorded this species above 1,400 metres (4,600 ft), with most birds found between 1,800 metres (5,900 ft) and the highest elevations of the study area, 2,000 metres (6,600 ft).

Migrazione

Resident species

Conservazione

Tendenza della popolazione

stable