A flash of iridescent green and a high-pitched buzz of wings signal the presence of the Garden Emerald (Chlorostilbon assimilis), a small hummingbird species endemic to the Pacific lowlands of Costa Rica and western Panama. Despite its vibrant appearance, this species often goes unnoticed, thriving in disturbed areas such as gardens, forest edges, and secondary growth, rather than pristine rainforest interiors.

Males are unmistakable with their glittering emerald plumage and deeply forked tails, while females are more subdued, with pale underparts and a white postocular stripe. The species is primarily nectarivorous, favoring small tubular flowers, but like many hummingbirds, it supplements its diet with tiny arthropods.

Adaptable and resilient, the Garden Emerald has benefited from habitat alteration that has created the open and semi-open environments it prefers. Though sometimes confused with similar species like the Canivet’s Emerald, its restricted range and specific habitat preferences make it a key species for understanding ecological responses to land use change in Central American lowland ecosystems.

Source: Stiles, F. Gary & Skutch, Alexander F. (1989). A Guide to the Birds of Costa Rica. Cornell University Press.