The Short-Legged Wader

COURTESY MARSHBUNNY.
When they handed out necks and legs in the wading bird category, the green heron must have showed up late. We think of herons and egrets (not to mention cranes and storks) as having the longest necks and legs of any birds. Their dagger-like bills are mounted at the end of what amounts to a combination of a Slinky and a hydraulic arm. Most of us have watched them hunt. As the “wading bird” designation suggests, they tend to stand up to their hips, as it were, in a pond or stream and stalk slowly or stand stock-still before suddenly launching their bill at a hapless fish, frog, or crayfish. They will then swallow their prey whole.

Some of the more impressive wildlife photographs I have seen have captured green herons in the act of hunting. Because they are small—they are frequently described as crow-sized—they can’t wade in very deep water. And because their necks are short, they tend to lunge with their entire body, sometimes quite acrobatically. If they end up in the drink, that’s OK. As it turns out, they can swim.

Green herons are subtly green. The feathers of their crown, nape and back are a dark green and are raised in a ragged crest when the bird is agitated. The wings are more iridescent and can shimmer between bluish and greenish depending on the light. The belly and undertail coverts are a soft olive. However, you are more likely to notice the large patches of chestnut down the sides of the neck between the eyes and the wings. These are separated by a white throat and chest that is covered with broad brown streaks. This feature varies quite a bit in width and prominence. The females tend to be slightly smaller and lighter colored than the males.

Butorides virescens is widely distributed through North America, the Caribbean and Central America, where its range overlaps with the related striated heron (B. striata). During the 1970s, these two species were lumped into one called the green-backed heron and then—based on analysis of the same specimens by different workers—separated into two species again early in this century. This relationship is still unresolved, as are the number of subspecies of either species. B. virescens has four recognized subspecies at this time, and our eastern birds are members of the nominate subspecies B. virescens virescens, which is the darkest and greenest of them all.

Aside from the great blue heron and the American bittern, most members of this family are at the northern edge of their breeding range in New Hampshire. According to the Atlas of Breeding Birds of New Hampshire (1994), the green heron is one of four species in this family (Ardeidae) to breed in the state. The

others are the great blue, the American bittern, and the black-crowned night-heron. In the first decade of the 21st century snowy egrets bred on Star Island in the Isles of Shoals, but raccoons drove them out. Least bitterns have been seen at several locations, but there has been no documented breeding and it is a Species of Special Concern in the state.

The green heron winters along the Gulf Coast and in the Caribbean. According to Stephen Mirick’s entry on this bird in the Atlas, it arrives in late April and May and the males establish territories, defending them with “full forward displays.” William Davis and James Kushlan describe these at birdsoftheworld.org: “… head and neck fully forward, feathers fully erect, eyes bulging, bill open showing red lining of mouth, vigorous tail-flipping; then lunges at opponent with wings slightly extended, uttering raaah calls.” In addition to their own species, green herons will also drive away crows and grackles from their nests. Humans are not welcome either and will be greeted by a bird that “call[s] aggressively, with harsh croaks, elongating neck, fluffing feathers, and raising crest.”

The females go from male to male until they select one with whom to mate. The males supply the nest material, and the female does the building. Like most herons, B. virescens constructs a flimsy structure of sticks in a tree near water between 10 and 30 feet from the ground. Unlike many herons, it tends to be a solitary nester. Here in the northern part of their range, they typically raise only one brood. By late July, the young are generally independent of their parents.

Herons are well known for their wide-ranging post-breeding dispersals. Many of the sightings of heron, egret, and ibis species recorded in The Birds of New Hampshire (2013) and in the NH Bird Forum are from late summer and early fall, when members of this family are regularly seen well outside their breeding ranges. The green heron wanders less widely than most, but its frequent occurrence on islands has been attributed to post-breeding dispersals. It migrates south to its wintering grounds in October.

In New Hampshire the green heron is most common in the southeast and seems to follow the Merrimack and Pemigewasset river valleys north and west into the interior. It is less often seen in the Connecticut Valley on the far side of the western highlands.

If you encounter a green heron, watch it fish. You may see it use bait. This species has been known to break up pieces of stick and float them on the water while it crouches motionless nearby. This kind of toolmaking is rare among birds. Green herons are also known to use pieces of Styrofoam, berries, insects, feathers, and one was even seen digging up earthworms and deploying them. They engage in this sort of behavior more often in places that have few suitable perches to give these short-legged herons access to deeper water. As ever, necessity is the mother of invention.

Bill Chaisson has been a birdwatcher for over 50 years. He lives and works in Wilmot. Contact him at [email protected].