About Cynanthus auriceps (Gould, 1852)
Description: The golden-crowned emerald (Cynanthus auriceps) measures 7.5 to 9.5 cm (3.0 to 3.7 in) in length and weighs approximately 2.2 g (0.078 oz). The adult male has a brilliant golden green crown, with the rest of its upperparts ranging from duller golden green to bronzy green. Its underparts shift from an almost pure green on the chin and throat to brilliant golden green at the vent. The tail is long and deeply forked; the tail feathers are black with a violet-bluish gloss, and the central three pairs have broad brownish gray tips. Adult females share the same upperpart coloration as males. Their underparts are light gray, palest on the belly and vent. Their cheeks are dusky, with a grayish white streak behind the eye. Females also have a forked tail, but it is much shorter than the male's; the central tail feathers are bluish green to bronze green, and most have a black band near the tip and gray tips. Males have a red bill with a black tip, while females have a red mandible with a black tip and a black maxilla.
Distribution and habitat: The golden-crowned emerald is found in western Mexico, ranging from Sinaloa south to eastern Oaxaca, and also extends inland up the Balsas River basin to southern Morelos. It inhabits tropical dry forest at elevations between sea level and 1,800 m (5,910 ft).
