Tuesday, July 23, 2013

Native Species Profile - Green Heron

If you have ever canoed or kayaked down a river in Mid-Michigan (or just about anywhere else in eastern North America), at some point a stocky bird has erupted from the riverbank or from the trees overhead and took off downstream screaming a call that sounds like "Skeow! Skeow!"

This skeow cry is the unmistakeable alarm call of the Green Heron (Butorides virescens). 

Juvenile Green Heron (Butorides virescens)

The Green Heron (sometimes called the Green-backed Heron) is the smallest heron found in the Eastern United States.  It reaches a height of only 16-18 inches (41-46 cm) and has a wingspan of 25-25 inches (64-68 cm).  Like most birds, it weighs very little for its size, hitting the scales at around 8 ounces (240 grams).  Despite its small size, it does not have the appearance of a fragile bird.  Unlike the long graceful look of most herons, the Green Heron looks stocky.

A migratory species, the Green Heron is found in Mid-Michigan (and most of the eastern United States) only in the warmer months of the year.  During the Summer, the species can also be found up and down the West Coast.Like all herons, the Green Heron is primarily a wetland species.  It hunts for small fish, frogs, insects and other invertebrates, small reptiles, and small mammals in shallow water in various wetland habitats.  The Green Heron hunts by wading slowly through shallow water and then extending its neck, plunging its spear-shaped beak after its prey.  The Green Heron also occasionally plunges into deeper water from overhanging vegetation.

Adult Green Heron (Butorides virescens)

From a distance, the Green Heron appears as an overall dark color.  Upon closer inspection, different colors are visible.  The back is a dark green color.  The sides are a rich chestnut brown.  The chest is often streaked with white, especially on juvenile birds.  The bird sports a cap of dark green (a shade darker than the back) that is sometimes raised into a crest.  Adult birds have a dark beak while the beaks of juveniles are partly yellow.  Both adults and juveniles have long yellow legs.  Another striking feature of the Green Heron is its bright yellow eyes.  This overall drab color scheme and its diminitive size (for a heron) can make the Green heron difficult to spot against a backdrop of shoreline vegetation or when it perches in trees.  Often the first indication of a Green Heron is that "Skeow!" alarm call as the heron flies away indignantly.

Green Heron (Butorides virescens) among White Water Lily pads.

Basic Information

Green Heron 
Butorides virenscens

Size:  16-18” long, 25-27” wingspan

Habitat:  marshes, swamps, rivers, streams, lake edges, flooded fields

Eats:  small fish, invertebrates, insects, frogs, other small animals

Nest:  in a small tree or shrub, basket of sticks, nests in small colonies

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