The Green-crowned Brilliant has a loud squeaky kyew call.

The male Green-crowned Brilliant is 13 cm long and weighs 9.5 g. It is mainly bronze-green with a glittering green crown, forehead, throat and breast.

In order to attract their main pollinators, the nectarivorous Green-crowned Brilliant (Heliodoxa jacula), they instead use the markings on their leaves.

The Green-crowned Brilliant (Heliodoxa jacula) is a large robust hummingbird that is a resident breeder in the highlands from Costa Rica to western Ecuador.