The black-thighed grosbeak (Pheucticus tibialis) is a large seed-eating bird in the family Cardinalidae, which is endemic to the mountains of Costa Rica and western Panama. This species breeds from about 1000 m altitude (Pacific slope) or 1500 m (Caribbean slope) up to 2600 m and is found in canopy, woodland edge and semi-open habitats such as pasture with some trees. The nest is a thin cup constructed on a bulky twig base 1 – up in a small tree or amongst vines. The female lays two brown-spotted pale blue eggs between March and May. The adult black-thighed grosbeak is 20 cm long, weighs 70 g, and has a massive grey bill. The male has a yellow head, rump and underparts, an olive-edged black back, and black wings, thighs and tail. There is a white patch on the flight feathers. The female is paler with more olive on the back and a smaller white wing patch. Immatures are duller and more olive-tinged, and have streaking and mottling on the body plumage. The black-thighed grosbeak forages in shrubs or trees for insects, seeds and berries. The call is a sharp pink, and the song is a musical stream of warbles, whistles, trills and slurs.