Green Heron
Butorides virescens
Pelecaniformes Order – Ardeidae Family
BIOMETRICS:
Length : 40-48 cm
Wingspan : 62-70 cm
Weight : 240g
LONGEVITE: Up to 8 years
DESCRIPTION:
Green Heron adult has grey blue back and wings. Belly, foreneck and chin are white. Back, sides of neck and head are chestnut. Crown is greenish-black. Legs are orange.
Bill is black, with yellowish lores and upper mandible base. In breeding period, it is completely black. The tip is long and sharp.
Fr: Héron vert
All : Grünreiher
Esp: Garcita verdosau
Ital: Airone verde
Nd: Kleine Groene Reiger
Russe: Кваква зеленоспинная
Sd: Grönryggad häger
Photographs:
Alfredo Colón
Puerto Rico Wildlife
Text by Nicole Bouglouan
Sources:
HANDBOOK OF THE BIRDS OF THE WORLD vol 1 by Josep del Hoyo-Andrew Elliot-Jordi Sargatal - Lynx Edicions - ISBN: 8487334105
FIELD GUIDE TO THE BIRDS OF NORTH AMERICA by National Geographic Society - National Geographic Society - ISBN: 0792274512
A GUIDE TO THE BIRDS OF MEXICO AND NORTHERN CENTRAL AMERICA by Steve N. G. Howell, Sophie Webb - Oxford University Press - ISBN: 0198540124
Animal Diversity Web (University of Michigan Museum of Zoology)
All About Birds (Cornell Lab of Ornithology)
Wikipedia (Wikipedia, The Free Encyclopedia)
Adult female is slightly smaller, with paler and duller plumage, especially in breeding period.
Immature is duller, with streaked neck and yellow legs.
VOICE: SOUNDS BY XENO-CANTO
Green Heron is usually silent, but when excited or alarmed, he gives a raucous "kyowk-kyowk". We can also hear a short warbling, also a sharp "kah-kah-kahah", and a drawling "raaaahhh, raaahhh". Other sounds are uttered during the courtship displays.
HABITAT:
Green Heron lives in the wooded vicinity of fresh, brackish or salty streams. We can see it in mangroves, sandy beaches, shores of rivers and streams. We find it from sea level up to 1800 m of elevation.
RANGE:
Green Heron comes from Americas. We find it in North America, Central America, and Caribbean. Populations living on the East and West coasts are sedentary. However, those living in the interior of North America are migratory, flying southwards after breeding season, in mid-September.
BEHAVIOUR:
Green Heron nests in its feeding areas. It fishes in several manners, either by standing upright in the water or on a low perch above water, to watch for prey, or by tracking down its prey. It can occasionally swim in order to pursue a prey. At other times, it retracts its neck, with bill downwards, while it aims for a prey, and after some cautious steps, it stabs the fish with the bill. It feeds alone or in pair.
When Green Heron is threatened, alarmed or aggressive, it erects its crest, holds the neck and flutters its short tail. It is a territorial bird which does not tolerate any intrusion. It attacks on sight while flying towards the intruder, repeating loud and guttural "annnck-annnnck". This same call is repeated as an alarm. It takes off very easily and in an unexpected way, and this behaviour often allows identifying it. It is a shy bird.
Courtship display is stereotyped. Green heron male performs circular flight similar to a natural flight, but directed towards the breeding area and accompanied with calls.
From then on, courtship displays become aggressive. Chasing, circling and bold displays are used while giving raucous "raah-raah", displaying the reddish chin’s stripes. Or male flies with exaggerated wing beats, producing a muffled rustle, with posture “retracted neck”, and with fluffed crest, neck and scapulars, uttering a “roo-roo” before landing.
Flight displays are interspersed with ground displays, showing male perched, with head and neck downwards, with bill tip at toes level, snapping bill, with fluffed feathers.
Or, on the contrary, it throws its head backwards until touching the erected scapulars, bobbing head and neck from side to side, with flattened crest, breast and flanks feathers, with bulging eyes and iris turning from yellow to dark orange, while it utters a deep "aaroo-aaroo".
Male performing these displays in front of a female is allowed to enter the nest-site. Female performs the same displays, but silent and quieter, creating pair bonds. Male stops its displays, and pairs starts mutual preening accompanied by snapping bills.
Copulation occurs in the nest during the construction. Several copulations occur, interspersed with quiet moments.
FLIGHT:
Green Heron flies with regular and steady wing beats. Courtship displays show its agility in flight.
REPRODUCTION:
Green Heron nests alone or in loose groups. The male protects the nest-site during the nest construction. Both mates build a platform made with sticks and stems, in bushes or trees, near or above water. It is rather a bit basic.
Female lays 2 to 4 eggs. Incubation lasts about 21 to 25 days, shared by both parents. Altricial chicks are fed by both adults. They leave the nest at about 32 to 35 days after hatching. They still depend from their parents during about a month after fledging. They reach their sexual maturity at one year.
DIET:
Green Heron feeds on fish, insects, invertebrates and amphibians. It also consumes earth worms, leeches, dragonflies, grasshoppers and crayfish, also small rodents, lizards, frogs, tadpoles and snakes.
PROTECTION/THREATS/ STATUS:
Green Heron populations are threatened by degradation of habitat, wetland drainage, and bad water quality.
Snakes and corvidae eat the eggs, raccoons eat chicks, and the adults are preyed upon by birds of prey.
