There is little information about the breeding biology of Golden-crowned Emerald. Breeding is reported from February-July (Howell and Webb 1995), although the only detailed descriptions are of nests encountered in March and April (Wolf 1964, Rowley 1966). The nest is a small cup placed low near the ground (ca 0.7-1 m above the ground, n = 2); the dimensions of one nest were outside diameter 47 mm, inside diameter 25 mm, nest cup 20 mm deep (Wolf 1964). The clutch is two, and the eggs are white and unmarked. Dimensions of one egg were 11.9 x 7.2 mm (Rowley 1966). Only the female attends the nest. The nestling period is ca 24-25 days (Wolf 1964).