| Yellow-faced grassquit | |
|---|---|
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| Male in Jamaica | |
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| Female in Jamaica | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Thraupidae |
| Genus: | Tiaris Swainson, 1827 |
| Species: | T. olivaceus |
| Binomial name | |
| Tiaris olivaceus (Linnaeus, 1766) | |
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| Synonyms | |
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Theyellow-faced grassquit (Tiaris olivaceus) is apasserinebird in the tanager familyThraupidae and is the only member of the genusTiaris. It is native toCentral America,South America, and theCaribbean.
In 1760 the French zoologistMathurin Jacques Brisson included a description of the yellow-faced grassquit in hisOrnithologie based on a specimen collected inSaint-Domingue (nowHaiti). He used the French nameLe bruant de S. Domingue and the Latin nameEmberiza dominicensis.[2] Although Brisson coined Latin names, these do not conform to thebinomial system and are not recognised by theInternational Commission on Zoological Nomenclature.[3] When in 1766 the Swedish naturalistCarl Linnaeus updated hisSystema Naturae for thetwelfth edition he added 240 species that had been previously described by Brisson.[3] One of these was the yellow-faced grassquit. Linnaeus included a terse description, coined thebinomial nameEmberiza olivacea and cited Brisson's work.[4] Thespecific nameolivaceus isNeo-Latin for "olive-green".[5] This is now the only species placed in thegenusTiaris that was introduced by the English naturalistWilliam Swainson in 1827.[6] The genus formerly contained additional species. A molecular phylogenetic study published in 2014 found that the genus was non-monophyletic and in the subsequent rearrangement four species were moved to other genera.[7][8][9]
The yellow-faced grassquit was traditionally placed with the buntings andNew World sparrows in the familyEmberizidae,[10] butmolecular phylogenetic studies have shown that it is a member of the tanager familyThraupidae and belongs to thesubfamily Coerebinae that also containsDarwin's finches.[7]
Fivesubspecies are recognised:[9]
It is a small bird with a conical bill, sharper than that of the relatedseedeaters. It is 10–10.7 cm (3.9–4.2 in) long and weighs about 8–10 g (0.28–0.35 oz), depending onsubspecies. The adult male has an olive-green back, and its face and breast are black apart from a bright yellow throat,supercilia, and lower eyelid spot. The rest of the underparts are greyish olive. Thebeak and eyes are dark, while the legs are grey.[11][12][13]
The adult female is slightly smaller on average than the male. It is dull olive-green above and paler grey below, and may have some dark breast smudges. The yellow face pattern is much weaker and duller, and may be almost invisible. The lower part of the beak is dark horn-colored (light grey). Young birds are coloured essentially like the adult female, but duller and greyer. Young males begin to acquire full adult plumage in their first year.[11][12]
The yellow-faced grassquit has a weak buzzing trilledttttt-tee call. The song is a varying series of high thin rapid trills. Given for a prolonged time, it is melodious, yet subdued, and often only heard from a short distance away.[12][13]
It breeds from central Mexico to northern Ecuador and north-western Venezuela, and also on theGreater Antilles and nearby islands. It is not amigratory bird but moves about outside the breeding season; vagrants have been recorded in southernTexas andFlorida. It has been introduced toHawaii.[11][12][13]
The yellow-faced grassquit is a common to abundant resident in lowlands and foothills up to 2,300 m (7,500 ft) altitude in semi-open areas such as roadsides, pasture, weedy fields and low scrub. It avoids dry grassland and other very low growth, but will readily utilize neglected gardens wherelawn grass has grown high. It is a fairly sociable bird, sometimes forming loose flocks with othertanagers (such asseedeaters) andemberizids that share its lifestyle. Occasionally, adult males will come together to perch in a shrub and sing.[12][13]
This species feeds mainly ongrass seeds, but also takes other seeds, berries and someinsects. Food is typically plucked from theinflorescences directly, or gathered from the ground. Animal prey is hunted amongfoliage in aNew World warbler-like fashion.[12]
The main breeding season is in the summer months, but except for February to April birds may nest at other times of the year. This species sometimes forms loose nesting colonies. During courtship, the male vibrates his wings as he sings his subdued song, sitting only 1–2 in (2.5–5.1 cm) away so the female can properly hear him. The roughly globular nest, built by the female, is made of grass and weed stems compacted into a thick mass, and lined with pieces of grass inflorescences andbast fibre. It has a side entrance and is placed usually less than 30 cm (12 in) above the ground, often among grass or weeds on a road or riverembankment. Occasionally, the species nests in shrubs up to 1.5 m (4.9 ft) above the ground. Theclutch is two or three, rarely four, brown-speckled white eggs. They are incubated by the female alone for 12–14 days to hatching.[12][13]
This bird is not rare and widely distributed; it is thus classified a species ofLeast Concern by theIUCN. It seems to benefit fromdeforestation, increasing in numbers and expanding its range; for example, it is only since 1997 known from the easternAndean slope ofMeta Department inColombia.[1][14]
