Black-crowned Antshrike

The black-crowned antshrike is 14 to 15 cm (5.5 to 5.9 in) long and weighs 20 to 28.5 g (0.71 to 1.0 oz). Members of genus Thamnophilus are largish members of the antbird family; all have stout bills with a hook like those of true shrikes. This species exhibits significant sexual dimorphism. Adult males of the nominate subspecies have slaty gray upperparts with a gray forehead, a black crown and nape, a hidden white patch between their scapulars, and white-tipped black uppertail coverts. Their face is grizzled gray. Their wings are black with white tips on the coverts and white or gray edges on the flight feathers. Their tail is black with a white spot at the end of each feather. Their underparts, including the underside of their tail, are slaty gray. Adult females have brown to buffy brown upperparts. Their wings are fuscous-black with brown edges and white tips on the flight feathers. Their underparts are buffy brown to grayish brown. Both sexes have a brownish red to chocolate-brown iris and medium to dark gray legs and feet. Males have a dark gray bill and females light gray. Juveniles have dull cinnamon-brown upperparts and grayish white underparts. Males of subspecies T. a. gorgonae have more gray on their forehead and lighter gray underparts than the nominate. Females of gorgonae have a much darker crown, more rufous upperparts, and darker underparts than the nominate.

The nominate subspecies of the black-crowned antshrike has by far the larger range of the two. In Central America it is found on the Caribbean slope from southern Belize through Panama and on the Pacific slope in northwestern Costa Rica and in Panama from Coclé Province east. In South America it is found across northern Colombia including the Magdalena Valley and northwestern Venezuela as far as Trujillo state, and along the Pacific slope of Colombia and Ecuador into far northwestern Peru's Department of Tumbes. Subspecies T. a. gorgonae is found only on Gorgona Island of the southwestern coast of Colombia. The black-crowned antshrike inhabits a variety of forested landscapes including primary and secondary semi-deciduous and evergreen forests. It favors the forest interior but does occur at its edges. It also favors the understorey to mid-storey but occurs all the way to the canopy. In elevation it ranges from sea level to 1,250 m (4,100 ft) in Central America, to 1,500 m (4,900 ft) in Colombia, mostly below 1,100 m (3,600 ft) in Ecuador, and to 1,000 m (3,300 ft) in Venezuela. In Peru it occurs between 400 and 800 m (1,300 and 2,600 ft).

The black-crowned antshrike feeds on a wide variety of insects and other arthropods, and has been observed capturing small lizards. It usually forages singly or in pairs and almost always joins mixed-species feeding flocks that pass through its territory. It usually forages in the understorey and mid-storey but has been observed feeding as high as 22 m (70 ft). It forages methodically, by gleaning prey while perched, with short upward sallies, while briefly hovering, by chasing in mid-air, and by flipping over leaves on the ground. It takes prey from live and dead leaves and palm fronds, branches, vines, spiderwebs, and moss. It sometimes follows the edges of army ant swarms in its territory.