Thick-billed Euphonia Euphonia laniirostris Scientific name definitions

The Thick-billed Euphonia is distributed from Costa Rica south to southern Amazonia. Despite its name, the size of the bill is of extremely limited use in the identification process. The species is mostly found below 1200 m in secondary woodland, forest borders, and scrubby clearings and gardens. It is typically encountered in pairs or small groups, like most euphonias, and often joins mixed-species flocks, especially those dominated by tanagers. Males are mainly glossy steel blue with a yellow forecrown patch that reaches to just behind the eye, and bright yellow underparts including the throat. Females are, like those of most euphonias, much duller, being olive above and yellow below.

10 cm; 13–16·5 g. Rather small euphonia with relatively thick bill deeper than that of most congeners. Male nominate race has yellow forehead to mid-crown (a little past eye); side of head, rear crown, nape and upperparts glossy blue-black; uppertail dark blue; upperwing-coverts and flight-feathers dusky, tinged dark blue; throat and entire underparts bright yellow; undertail dark grey, inner webs of outer 2–3 feather pairs mostly white (forming two large white ovals on undersurface of tail); iris dark brown; bill blackish, base of lower mandible blue-grey; legs dark grey. Female is yellowish olive-green above, greenish-yellow below, paler on undertail-coverts. Immature is similar to female; subadult male (second full year) is olive above, forecrown yellow with olive mottling, variable amount of black on side of head (usually forming mask), throat and chest yellow, sides, flanks and lower underparts mostly olive. Race <em>crassirostris</em> male is similar to nominate, but yellow of crown extends farther backwards, especially in centre; hypoxantha male differs in having whole crown lemon-yellow, and underparts lighter and brighter yellow; <em>melanura</em> male has crown like nominate, but underparts darker, orange-yellow, and undertail entirely dark grey (no white), female similar to nominate, but darker below; <em>zopholega</em> male is similar to nominate, but white ovals on undertail smaller.

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Small fruits and berries. Mistletoe (Loranthaceae) comprises a large proportion of diet, but also eats berries of melastomes, figs (Ficus) etc.; in Colombia recorded as eating fruits of Aiphanes (a spiny palm) and Sapium (Euphorbiaceae). Contents of five stomachs were vegetable matter, including fruit and seeds. Found mostly in pairs or small groups that forage and wander alone or sometimes associate with mixed-species flocks along wooded borders; also sometimes with other members of genus, especially around mistletoe. Like many euphonias, may rest or call from high or semi-open perch. Forages mostly in higher part of trees; occasionally drops low along shrubby borders.

Breeding reported in Mar–Sept in Panama, and season probably similar in Costa Rica; Dec and Jan and birds in breeding condition in Apr–Jul in Colombia; nest-building observed in early Mar in SW Ecuador (at Tambo Negro, in Loja); two, rarely three, broods in a year reported. Nests of some pairs visited by possible helpers, but feeding of nestlings by latter not verified. Nest built by both sexes , but female may reweave much of her mate’s contribution; a globular structure with small circular entrance on side, sometimes also with small porch or overhang, composed of fine twigs, fibres and leaves, lined with dry grass, usually built on or within 3 m of ground, occasionally much higher (to 15 m in Venezuela), generally well hidden in cavity in trunk, post, on epiphyte-covered or vine-covered limb, or branch fork; nest occasionally reused (such reused nests found to be lined with strips of dried Heliconia or banana leaves); reported also as appropriating nest of Great Kiskadee (Pitangus sulphuratus) built c. 6 m up and atop nest of a thornbird (Phacellodomus). Clutch 2–5 eggs, white or pinkish-white, speckled and marked with brown, especially at large end; at two nests, incubation period 14–16 days, chicks fed by both parents, nest­ling period 18–21 days. Male may breed in subadult plumage, when in second full year.