Blue-fronted Lancebill

The blue-fronted lancebill is 9.6 to 11 cm (3.8 to 4.3 in) long. Males weigh 3 to 5 g (0.11 to 0.18 oz) and females 3.3 to 6 g (0.12 to 0.21 oz). Both sexes have a long straight to slightly upcurved bill, and often hold it at an upward angle. Males of the nominate subspecies have a violet forehead ("front"), a bronze nape, and otherwise dark bronzy green upperparts. The tail is short and blue-black. The underparts are blue-black with a bluish green gloss on the throat and breast. The female differs from the male by having a greenish blue forehead and dull grayish bronzy green underparts. Both sexes of D. j. guianensis have a shorter bill than the nominate and are overall paler but similarly colored.

The nominate subspecies of blue-fronted lancebill is found on the east slope of the Andes from east central Colombia south through eastern Ecuador to central and southeastern Peru. It inhabits wet forests of lower Andean slopes and foothills and the adjacent lowlands. It favors ravines, gorges, and rock outcroppings and usually occurs from the forest's middle strata into the lower canopy. However, it occurs down to the shrub level at forest edges. In elevation it mostly ranges between 800 and 1,200 m (2,620 and 3,940 ft). D. j. guianensis is found disjunctly in southeastern Venezuela, western Guyana, and slightly into adjoining northern Brazil. It inhabits tropical and subtropical forests on the area's tepuis, mostly at elevations between 900 and 2,000 m (2,950 and 6,560 ft), and does not occur in the lowlands between them.

The blue-fronted lancebill's diet is nectar and small arthropods. It draws the former from tubular flowers, typically those that droop or are horizontal. It does not usually defend feeding territories. It catches arthropods on the wing or by hover-gleaning from vegetation.