Golden-crowned Emerald

The golden-crowned emerald is 7.5 to 9.5 cm (3.0 to 3.7 in) long and weighs about 2.2 g (0.078 oz). The adult male's crown is brilliant golden green and the rest of its upperparts duller golden green to bronzy green. Its underparts transition from an almost pure green on the chin and throat to brilliant golden green at the vent. The tail is long and deeply forked; its feathers are black with a violet-bluish gloss, and the central three pairs have broad brownish gray tips. The adult female's upperparts are like the male's. Its underparts are light gray that is palest on the belly and vent. Its cheeks are dusky with a grayish white streak behind the eye. Its tail is also forked but much shorter than the male's; the central feathers are bluish green to bronze green and most have a black band near the end and gray tips. The male's bill is red with a black tip, the female's mandible is red with a black tip and the maxilla is black.

The golden-crowned emerald is found in western Mexico from Sinaloa south to eastern Oaxaca and also inland up the Balsas River basin to southern Morelos. It inhabits tropical dry forest at elevations from sea level to 1,800 m (5,910 ft).

The golden-crowned emerald is a "trap-line" feeder, visiting a circuit of flowering plants to take nectar. They wag their tail and spread its fork as they feed. In addition to nectar, they take insects from foliage.