Green Heron

Green Heron (Butorides virescens)Spanish name: Garcilla Verde

About The Green Heron

Habitat
These birds are found where slow water meets thick vegetation, in many streams, ponds, marshes, and mangroves. They can be found at elevations from 0 to 1,850 m.

Range
The Green Heron is mostly a permanent resident on the Caribbean side and in the central part of the country, although migrants and winter visitors also tend to arrive in September in the northern Caribbean region of Costa Rica. This heron is abundant in lowlands on both slopes, especially on the Pacific side and in Isla del Coco. The full range of this bird includes from southern Canada to Chile, as well as many places outside of the Americas. North American populations winter in Colombia and Venezuela, but populations in warmer southern regions tend to reside there all year.

National Parks

Palo Verde National Park, Tortuguero National Park, Corcovado National Park; sometimes in La Selva or Santa Rosa National Park.

Physical Description/ Interesting Biology
In Costa Rica this bright bird can be found along the edges of many waterways which have shallow and slow water bordered by dense vegetation. The Green Heron may be the most widespread water bird in the country: some populations have permanent residents while other Green Herons migrate and winter in Costa Rica's agreeable climate. It is obvious when a Green Heron has been disturbed, because it protests loudly and bursts out of the water to rush into the underbrush to escape. Adults may even snarl if an intruder happens upon their nest. Otherwise, these birds are often quietly stalking among the water plants, looking for prey.

This heron forages alone by freezing still in water and waiting for small, slow aquatic prey to cross its path, when it briskly strikes with its bill. It may forage in open water as well as near the bank, but escapes danger by retreating to vegetation. The Green-backed Heron is capable of adapting to many kinds of aquatic habitat; it is agile and can maneuver deftly through the tangled sort of plants that often grow in or near water.

Green Herons come together to breed in pairs and occasionally in colonies where there are dense populations. They build loose platform nests in trees or other vegetation hanging 1 to 5 meters up over the water. Female Green Herons in Costa Rica lay 2 pastel bluish green eggs per clutch; birds in more northern populations lay 4 to 5 eggs at a time, and some suggest that clutches with as many as 6 eggs may be laid by more than one female.

Males and females of this species have similar plumage, although males are relatively larger. Both have small, stout bodies with long legs and a short, shaggy neck. They are named for their lustrous, dark green back and wings; the belly is gray below a white throat and neck stripe. They have a flat crest of a darker green, and brownish maroon on the face and sides of the neck. In southwestern Costa Rica and Panama, individuals of this species may be a solid brown.
The eyes, feet, legs, and lower part of the bill contrast in bright yellow.

Diet
The diet of this fish is constituted of small fish as well as frogs and water insects.

Height/Weight

Adult Green-backed Herons measure at 43 cm long and weigh 210 g.

Brief Taxonomy
Order: Ciconiiformes
Family: Ardeidae

Sources
Skutch, Alexander F. and F. Gary Stiles. A Guide to the Birds of Costa Rica. Utica: Cornell University Press,1989.
Stiles, F. G. in: Janzen, Daniel H. Costa Rican Natural History. Chicago: University of Chicago Press, 1983.

-Amy Strieter, Wildlife Writer