The green-tailed jacamar is 18 to 22 cm (7.1 to 8.7 in) long ands weighs 18 to 29 g (0.63 to 1.02 oz). The male's head, upperparts, and a band across the chest are metallic coppery green, somewhat bluer on the face. The tail is bluish green. The throat is white and the belly and vent area reddish chestnut. The female is similar but the throat is buff and the underparts are duller and paler.
The green-tailed jacamar is found from eastern Colombia's Vichada and Meta Departments east through southern and eastern Venezuela south of the Orinoco River to the Guianas and south in Brazil to the lower Madeira and Tapajós Rivers. It inhabits the borders, but not the interior, of several humid forest types including terra firme, várzea, gallery, and mangrove. It prefers open woodland, savanna, and shrublands, especially along watercourses. In elevation it ranges from sea level to 700 m (2,300 ft).
The green-tailed jacamar's diet is a large variety of insects though Hymenoptera predominate. It perches on exposed branches, often in pairs, and sallies from there to catch its flying prey.
The green-tailed jacamar excavates burrows in earth banks or arboreal termite nests. It has been documented breeding February to March in Venezuela, in May, June, and August in Suriname, and in April and September in Brazil.
