Butorides is from Middle English butor "bittern" and Ancient Greek -oides, "resembling", and virescens is Latin for "greenish".

Adults have a glossy, greenish-black cap, a greenish back and wings that are grey-black grading into green or blue, a chestnut neck with a white line down the front, grey underparts and short yellow legs.

Female adults tend to be smaller than males, and have duller and lighter plumage, particularly in the breeding season.

Juveniles are duller, with the head sides, neck and underparts streaked brown and white, tan-splotched back and wing coverts, and greenish-yellow legs and bill.

The habitat and foraging area of the green heron includes riparian zones, wetlands, ponds, and lakes, as well as human-made canals and ditches.

[citation needed] They mainly eat small fish, frogs and aquatic arthropods, but may take any invertebrate or vertebrate prey they can catch, including such animals like leeches, earthworms, dragonflies, damselflies, waterbugs, grasshoppers, spiders,[10] crayfish,[11] prawns,[10] mice, other rodents, lizards, tadpoles and snakes.

[11] Some of the many fish eaten are: minnows, sunfish, catfish, perch, eels and, in urban areas, goldfish.

[4][5][6] Green herons have been observed using captured prey (e.g. mayflies) or other objects (bread, feathers) to "bait-fish" – using a lure on the water's surface to attract fish.

The migration to the winter quarters starts in September; by late October, the birds are absent from regions where they do not stay all year.

At least the northward migration does not seem to be affected by global warming; birds appear in their breeding ranges at the same time they did 100 years ago.

The pairs form in the breeding range, after an intense courtship display by the males, who select the nesting sites and fly in front of the female noisily and with puffed-up head and neck plumage.