Garden Emerald Hummingbird Species

Among the over 300 species of hummingbirds found in the New World tropics, the Garden Emerald (Chlorostilbon assimilis) stands out as one of the most colorful and wide-ranging members of this captivating family of birds. Ranging from southern Mexico to Bolivia and southeastern Brazil, these tiny, glittering creatures thrive in a variety of habitats across their expansive territory. In this article, we will explore the identification, distribution, ecology, behavior, conservation status, and unique adaptations of the Garden Emerald hummingbird.


Reaching just 3 to 4 inches in length and weighing a mere 2 to 3 grams, the aptly named Garden Emerald can be easily distinguished by its vibrant plumage. The male has glittering emerald green feathers covering the entirety of its plumage, with the exception of its white underside from chin to vent. It has a straight black bill and dark feet. The female is similar, but has white tips on the tail feathers and some white spotting on the throat. Both sexes have a bold white postocular spot behind the eye.

The Garden Emerald’s tiny size, glittering green plumage, and range make it difficult to confuse with any other hummingbird species. The similar Veraguan Mango has a decurved bill, buffy rather than white undertail coverts, and is restricted in range to Panama and northwestern Colombia. The much larger Green-crowned Plovercrest of northern South America has extensive white markings on its tail and is easily distinguished by its unique crest.


The Garden Emerald has an exceptionally wide distribution across tropical regions of the Americas. Its range extends from southeastern Mexico through Central America into Colombia, Venezuela and Ecuador. From there, its range continues southeast, encompassing Peru, Bolivia, and south-central Brazil.

Within this broad territory, the Garden Emerald occupies a wide variety of habitats. It thrives in wet lowland forests and moist foothill areas, as well as drier habitats such as semi-open woodland, scrub, and gardens. This adaptability allows it to inhabit elevations from sea level up to 5,000 feet.


To fuel its nonstop motion, the Garden Emerald feeds on flower nectar from a variety of tropical plants, often visiting specialized hummingbird flowers with curved corollas perfectly adapted to the long bills of these tiny avians. Common nectar sources include plants in the Heliconia, Inga, Erythrina, Siphocampylus and Psittacanthus genera, among many others. The Garden Emerald will also visit flowers of many sizes, from small understory herbs to the crowns of towering Ceiba trees.

While feeding mainly on nectar, the species also consumes small insects which provide essential proteins. Aerial insectivory, pouncing on tiny insects from perches, is a common foraging strategy. The Garden Emerald may also glean small insects from foliage in a methodical, thorough manner unlike the more random aerial feeding.

Reproduction in this species occurs from December to June, varying within its broad range. The female constructs a tiny cup nest on a vertical branch, often overhanging water. Lichen and spider webs camouflage the outside, while soft plant down lines the interior. She lays two tiny white eggs and incubates them for 15 to 16 days. The chicks fledge in roughly 20 days. Males establish small territories centered around prime nectar sources which they defend vigorously from intruders. Their aggressive displays involve rapid vertical climbs with loud buzzing noises.

Conservation Status

With an extremely large range and increasing population trend, the Garden Emerald is evaluated as a species of Least Concern by the IUCN. Habitat loss represents the major threat, though its ability to adapt to human disturbance and occupy a wide variety of habitats helps minimize population declines. While thriving across most of its range, the species has declined in Costa Rica due to rapid deforestation. As with many Neotropical birds, researchers recommend continued monitoring of populations.

Unique Adaptations

The Garden Emerald exhibits many of the unique anatomical and physiological traits that enable hummingbirds to hover and thrive on their specialized nectar diet. Structural adaptations include strengthened leg and wing muscles for prolonged beating of their wings up to 70 times per second. Their heart rate can reach over 1200 beats per minute. Their wings are specially adapted to rotate in a full 180 degree arc for stability in hovering.

Long, specialized tongue and bill structures allow them to access nectar from specialized flowers. Hummingbirds have the highest metabolic rate for their size of any vertebrate. High-protein insect matter provides essential amino acids hummingbirds cannot obtain from nectar alone. In a remarkable example of extreme evolutionary specialization, hummingbirds rank among the smallest yet most metabolically intense vertebrates on Earth.


In terms of diversity, behavior, and specialized ecology, hummingbirds represent one of the most captivating avian families on the planet. The Garden Emerald stands out not only for its wide distribution and adaptable habitat use, but for its truly dazzling emerald plumage. Small yet mighty, resilient and captivating, this widespread Neotropical jewel highlights the wonders of an avian family unlike any other. When one has the chance to observe a Garden Emerald in action, darting from flower to flower in a blurred iridescence of green, it is easy to understand why hummingbirds have inspired centuries of human fascination.