Grimpar à bec ivoire

Identification

The ivory-billed woodcreeper is 20 to 26.5 cm (7.9 to 10 in) long. Males weigh 40 to 62 g (1.4 to 2.2 oz) and females 35 to 56 g (1.2 to 2.0 oz). It is a medium-sized member of genus Xiphorhynchus, with a long, fairly heavy, slightly decurved bill. The sexes have the same plumage. Adults of the nominate subspecies X. f. flavigaster have a face with fine buffy and blackish streaks, an indistinct buffy supercilium and eyering, and a faint dark stripe behind the eye. Their crown and nape are dark grayish brown with longish buff spots that are almost streaks. Their back and wing coverts are light grayish brown to olive-brown with blackish-edged buff streaks. Their rump, tail, and wings are chestnut. Their flight feathers are paler than the tail, with dusky tips on the outer primaries. Their throat is buffy with thin dusky streaks. Their upper breast is lighter than their throat and has a scaly appearance. The rest of their underparts are light buffy brown with dusky-edged buffy streaks that lessen to the belly. Their underwing coverts are ochraceous buff. Their iris is light reddish brown to dark brown, their bill pale with a brownish or bluish base to the maxilla, and their legs and feet yellowish green, olive-gray, or brownish. Juveniles are overall slightly darker than adults, with bolder streaks on the throat, duller streaks on the back and breast, and a brownish bill.<p>The other subspecies of the ivory-billed woodcreeper differ from the nominate and each other thus:<p>The subspecies have much individual variation that leads to weak differentiation among some of them. Most adjoining subspecies have intergrades.

Taxonomie

The ivory-billed woodcreeper has these eight subspecies:

Nom scientifique

Xiphorhynchus flavigaster

Autorité

Swainson, 1827

Ordre

Passériformes

Famille

Furnariidés

Genre

Xiphorhynchus

Répartition et habitat

The subspecies of the ivory-billed woodcreeper are found thus:<p>The ivory-billed woodcreeper inhabits a variety of forested landscapes. It favors deciduous woodland and also occurs in semi-deciduous forest, evergreen forest, gallery forest, pine-oak and pine forest, thorn scrub, freshwater swamps, and mangroves. It inhabits the interior and edges of both primary and secondary forest and also plantations. It tends to be in drier landscapes than many other woodcreepers. In elevation it mostly occurs from sea level to about 1,500 m (4,900 ft) but locally ranges up to 2,900 m (9,500 ft).

Migration

Resident species

Comportement

The ivory-billed woodcreeper is believe to be a year-round resident throughout its range, though some may move to higher elevations after breeding.<p>The ivory-billed woodcreeper's diet is mostly arthropods but also includes other invertebrates such as snails and small vertebrates, especially lizards. It usually forages singly, though sometimes in pairs, and regularly joins mixed-species feeding flocks and follows army ant swarms. Away from ants it usually forages from the forest's mid-level to the subcanopy but will go higher and lower. It hitches up trunks and along branches, often in a spiral and sometimes on the underside of branches. Most prey is taken by probing bark crevices, bromeliads, and epiphytes. It sometimes flakes off bark. When attending army ants it perches low and drops to the ground to catch prey disturbed by them.<p>The ivory-billed woodcreeper's breeding season appears to be March to August. It nests in a cavity or in a gap between Ficus roots and lines the nest with wood or bark chips or softer plant material. The clutch size is two to three eggs. The incubation period, time to fledging, and details of parental care are not known.<p>The ivory-billed woodcreeper's song in western Mexico is "piercing whistles in loud cascade that first ascends slightly and increases in volume before descending and slowing, 't-t-t-ttttttttt-t-tewtewtew-tew-tew' ". In northern Central America it is "a rapid trill, descending slightly in pitch at end" and in Costa Rica "a loud, laughing, descending whinny. Its calls include "tchee-oo", "skweeú", "squirp", and "tyew-tyew-tyew".

Conservation

Tendance de la population

declining