The Puerto Rican Emerald (Chlorostilbon maugeaus) is an endemic hummingbird of the archipelago of Puerto Rico.
The species displays sexual dimorphism with males and females differing in coloration. The males have iridescent green feathers on its body and a black tail while the female has a white tipped tail. They measure from 9 to 11 cm and weigh from 2.8 to 3.6 grams. This species is mainly found along the mountainous regions of Puerto Rico but it can also be found along the southwest coast of the main island. Puerto Rican Emeralds are highly territorial, often defending its territories with intense aerial pursuits.
Puerto Rican Emeralds feed on insects, spiders and nectar. They breed throughout the entire year but breeding is concentrated before the wet season starts from February to May. Eggs are extremely small, measuring 8 by 13 mm.
- List of endemic fauna of Puerto Rico
- List of Puerto Rican birds