From
a distance, the Green Heron is a dark, stocky bird hunched on slender
yellow legs at the waters edge, often hidden behind a tangle
of leaves. Seen up close, it is a striking bird with a velvet-green
back, rich chestnut body, and a dark cap often raised into a short
crest. These small herons crouch patiently to surprise fish with
a snatch of their daggerlike bill. They sometimes lure in fish using
small items such as twigs or insects as bait.
At a Glance
Habitat
|
Food
|
Nesting
|
Behavior
|
Conservation
|
|
|
|
|
|
Marsh
|
Fish
|
Tree
|
Stalking
|
Least Concern
|
Measurements
Both Sexes
Length
16.118.1
in
4146
cm
Wingspan
25.226.8
in
6468
cm
Weight
8.5 oz
240 g
Relative Size
About the
size of an American
Crow; smaller
than a Black-
crowned Night-Heron
Other Names
Green-backed
Heron (English)
Heron vert
(French)
Garcita verde
(Spanish)
|
Cool Facts
- The Green Heron is one of the worlds few tool-using
bird species. It creates fishing lures with bread crusts, insects,
earthworms, twigs, feathers, and other objects, dropping them
on the surface of the water to entice small fish.
- Like many herons, the Green Heron tends to wander outside
of its breeding range after the nesting season is over. Most of
the wanderers stay nearby as they search for good feeding habitat,
but some travel long distances. Individuals have turned up as
far away as England and France.
- The Green Heron is part of a complex of small herons that
sometimes are considered one species. When lumped, they are called
Green-backed Heron. When split, they are the Green Heron, the
widespread Striated Heron, and the Galapagos Heron.
- Green Herons usually hunt by wading in shallow water, but
occasionally they dive for deep-water prey and need to swim back
to shoreprobably with help from the webs between their middle
and outer toes. One juvenile heron was seen swimming gracefully
for more than 60 feet, sitting upright like a little swan,
according to one observer.
- The oldest Green Heron on record was 7 years, 11 months old.
Green Herons are common breeders in coastal and inland wetlands.
They nest along swamps, marshes, lakes, ponds, impoundments, and other
wet habitats with trees and shrubs to provide secluded nest sites.
They may even nest in dry woods and orchards as long as there is water
nearby for foraging. Green Herons spend the winter in southern coastal
areas of their range, and in marine and freshwater habitat throughout
Mexico and Central America. In tropical areas they are common in mangrove
swamps.
Green Herons eat mainly small fish such as minnows, sunfish, catfish,
pickerel, carp, perch, gobies, shad, silverside, eels, and goldfish.
They also feeds on insects, spiders, crustaceans, snails, amphibians,
reptiles, and rodents). They hunt by standing still at the waters
edge, in vegetation, or by walking slowly in shallow water. When a
fish approaches, the heron lunges and darts its head, grasping (or
sometimes spearing) the fish with its heavy bill. Occasionally Green
Herons hunt in deeper water by plunging on prey from above. They hunt
at all times of the day and night in the shallows of swamps, creeks,
marshes, ditches, ponds, and mangroves. They usually forage among
thick vegetation in water that is less than 4 inches deep, avoiding
the deeper and more open areas frequented by longer-legged herons.
Nesting
Nesting Facts
Clutch Size
35 eggs
Number of Broods
1-2 broods
Egg Length
1.31.7
in
3.44.3
cm
Egg Width
1.11.4
in
2.73.5
cm
Incubation Period
1921 days
Nestling Period
1617 days
Egg Description
Pale green to
bluish.
Condition at Hatching
Mostly helpless,
but with open
eyes. Covered
with grayish
brown down on
top and white
down beneath. |
Nest Description
The male begins building the nest before pairing up to breed, but
afterward passes off most of the construction to his mate. As the
male gathers long, thin sticks, the female shapes them into a nest
812 inches across, with a shallow depression averaging less
than 2 inches deep. The nest varies from solid to flimsy, and has
no lining. Green Herons sometimes renovate old nests, or build in
old nests of Black-crowned Night-Herons or Snowy Egrets. Occasionally
they take sticks from nearby old nests and refashion them into new
nests. They keep adding sticks throughout the breeding season.
The male selects a secluded site within his territory, usually
in a large fork of a tree or bush, with overhanging branches to conceal
the nest. Green Herons use many plant species as nest sites pines,
oaks, willows, box elder, cedar, honey locust, hickory, sassafrass,
and mangroves. The nest is usually on or over the water, but may be
up to a half-mile away. It may be anywhere from ground level to 30
feet off the ground (occasionally higher).
Each breeding season, Green Herons pair up with one mate apiece,
performing courtship displays that include stretching their necks,
snapping their bills, flying with exaggerated flaps, and calling loudly.
They often nest solitarily, although they may join colonies with other
Green Herons or with other species. They defend breeding areas from
each other and from birds like crows and grackles that prey on their
nests. Other predators include snakes and raccoons. Both the male
and female brood and feed the chicks, which may stay with their parents
for more than a month after leaving the nest, as they learn to forage.
Green Herons protect their feeding areas by driving away other species,
such as American Coots, that approach too closely.
Conservation
status via IUCN
|
|
Least Concern
|
Green Herons are still common, but their population suffered a
gradual decline of 1.6 percent per year from 1966 to 2010, resulting
in a cumulative decline of 51 percent, according to the North American
Breeding Bird Survey. Declines have been recorded across most of their
range, with only California populations showing an increase in that
time. Nevertheless, threats to the species are still rated as low
enough for the species to be categorized as low concern for North
America by the Waterbird Species Conservation Status Assessment. Green
Herons can be found throughout the year across the U.S. (with the
exception of several mid-western states), Central and northern South
America. A small percentage breeds in the southwest of Canada. In
the past, people hunted Green Herons for food and controlled their
numbers near fish hatcheries, where the herons were perceived as a
threat to the fish. Today, their biggest threat is probably habitat
loss through the draining or development of wetlands, although no
one knows the extent of this impact because these herons are solitary
and widely dispersed. |