| Olive warbler | |
|---|---|
 | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Peucedramidae Wolters, 1980 |
| Genus: | Peucedramus Coues, 1875 |
| Species: | P. taeniatus |
| Binomial name | |
| Peucedramus taeniatus (Du Bus de Gisignies, 1847) | |
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Theolive warbler (Peucedramus taeniatus) is a smallpasserinebird. It is the only member of the genusPeucedramus and thefamilyPeucedramidae.
This species breeds from southernArizona andNew Mexico,[2] USA, south through Mexico to Nicaragua. It is the only bird family endemic to North America (including Central America).[3] It was in the past classed with the Parulidae (New World warblers), but DNA studies suggest that it split early from the other related passerines, prior to the differentiation of the entire New World warbler/American sparrow/Icterid group. It is therefore now given a family of its own.
It is an insectivorous species of coniferous forests. Though it is often said to benon-migratory,[4] most New Mexican birds leave the state from November to late February.[5] It lays 3–4 eggs in a tree nest.
The olive warbler was originally placed in the New World warbler (family Parulidae) genusDendroica, a group which it closely resembles, particularly in having nineprimaries and similar skin. In spite of being assigned to its own genus in 1875, its affinities were a source of contention.[6] The shape of the basihyal bone in the skull, and aspects of its behaviour led to the suggestion that it was instead anOld World warbler in the family Sylviidae. That it was not in the family Parulidae was supported by the arrangement of muscles in the legs.DNA–DNA hybridization placed the olive warbler as an early branch of thefinch clade (which included the finches, cardinals andHawaiian honeycreepers) and the New World sparrow clade (which includes thetanagers,icterids and New World warblers),[7] and a 1998 study ofmitochondrial DNA confirmed its status as being far removed from the New World warblers.[8]
Thegeneric name of the olive warbler,Peucedramus, is derived from theGreekpeuke for a fir tree anddromos for runner, (fromtrekho, meaning run), a reference to its feeding habitat and behaviour. The species name,taeniatus, is from theLatintaenia for a headband, andatus for possessing, a reference to its facial markings.[9] The original specific name for the species wasolivaceus; however that name waspreoccupied and the name was changed.[10]
The olive warbler is a medium-sizedwarbler, 13 to 14 cm (5.1–5.5 in) in length and weighing 9.5 to 12 g (0.34–0.42 oz). It shows clinal variation in size, with more northern populations being larger than southern ones, a phenomenon known asBergmann's rule.[6] The olive warbler is a long-winged bird. Theplumage of the male is mostly grey body with some olive-green on the wings and two white wing bars. The male's head and breast are "tawny-orange",[4] and there is a black patch through the eye. In the female and juvenile, the orange is replaced by yellow, and the black mask is more diffuse. In addition to differences in size, plumage varies geographically as well, with southern birds having more brightly coloured plumage.
Thesong consists of clear whistles rendered ashirrJI hirrJI hirrJI,plida plida plida chir chir, etc.[4] The male sings throughout the year, with the frequency of the singing increasing in late winter and reaching a peak in early spring. During the year the male sings the most during the midmorning, but during spring the male sings constantly during mornings and late afternoon. Song is usually delivered from the canopy or other tall trees.[11]
The olive warbler is distributed from the southwestern United States toNicaragua, making it the only birdfamilyendemic to North America.[11] In the northern part of its range it has a continuous distribution fromYavapai County, Arizona and the southwestern tip ofNew Mexico along central Mexico to southern Mexico. It has adisjunct distribution across the rest of its range, with populations inTamaulipas,Coahuila andSonora andChihuahua in Mexico, and further south in southwestGuatemala and from northernEl Salvador and centralHonduras to northern Nicaragua.[11]
The olive warbler is a bird of mountains and highlands. In northern areas of its range it occurs from 2,600 m (8,500 ft) above sea level or more, in some parts of its range it may not occur below 3,500 m (11,500 ft). InOaxaca in Mexico it occupies a range of between 1,700–3,000 m (5,600–9,800 ft) further south in Guatemala it ranges down to 1,850 m (6,070 ft) and at the southern end of its range it can be found as low as 1,000 m (3,300 ft) in Honduras and in Nicaragua it occupies a belt of forest from 1,070–1,370 m (3,510–4,490 ft) .[11] They typically inhabit conifer forests, such asponderosa andsugar pine forests in Arizona,Abies common fir forests,oak, and pine forests in central Mexico, Guatemala, and Honduras. These forests range from humid to semi-arid.[6] In coastal regions stands of palms may be used, and in theValley of Mexico pine and alder forests are inhabited.[11]
Over most of its range the species isresident, but there is evidence that the most northerly populations arepartial migrants. Birds in Arizona, New Mexico, and Mexico apparently move away from their breeding grounds, although what exact movements are made is unclear. It has been suggested that they are either "down slope migrants", moving to lower elevations, or dispersive, as some records show their presence inTexas. Birds attributed to the northern raceP. t. arizonae have been recorded nearTepic, inNayarit. Nevertheless, some birds remain in the northern areas of their range year round.[11][12]
The olive warbler is an insectivore, taking insects and other arthropods. No specific information exists about the actual prey species taken, except that they will take the larvae ofTortricidae moths.[11] It forages in forests in the canopy and subcanopy. In feeds in the outer branches and twigs.[13] It mostly feeds in the branches of ponderosa pines, but also feeds in the branches ofgrey andsilverleaf oaks.[11]
