What Time is it in Nature: Green Heron
The Prairie Ridge pond is frequented by a variety of waterfowl and herons over the course of the year. The American Bittern that took up residence over the winter was a great addition to our species list, but a more common relative can be seen at the pond now, the Green Heron or Butorides virescens.
Green Herons are small, stocky members of the heron family of birds, Ardeidae. Green Heron adults are beautiful birds, sporting deep green feathers over their backs and chestnut feathers on their neck and breast. They have dark grey wings and a black crown that they can fluff up into a small crest when threatened. Juveniles are more brown and have streaks along the neck and spots on their wings. Green Herons are smaller than all herons but the Least Bitterns, reaching lengths of just 18 inches with a wingspan of just under 27 inches, about the size of the very common American Crow. Their legs are bright orange and much shorter than those of most herons. The colorful, short legs, dark feathers, and their tendency to hold their heads close to their bodies and hunch make the Green Herons very easy to tell apart from other small herons.
Green Herons are secretive and rather solitary birds. You’ll most often see them hunched over on a log or tree branch that extends over a wetland, swamp, or pond or sitting in densely leafy trees around the water’s edge. However, many people won’t notice they’re there at all until a bird is flushed from its hiding place and flies into the open while making a loud squawking call. Green Herons are excellent hunters, feeding opportunistically on whatever they can catch. Their diet consists primarily of fish, though they are also known to consume insects, spiders, crayfish, crabs, snails, amphibians, snakes, and the occasional mammal. They hunt by standing very still in very shallow water or on a perch over the water and watching for something to come into range. Then they’ll dart toward the prey with their beaks, either grabbing or spearing it before swallowing it.
Although they will occasionally build nests up to a half mile away from water, most Green Herons will construct their nests in a tree branch hanging over a pond, marsh, or wetland. Males begin the nest construction by selecting a site, ideally in the crook of a tree with overhanging vegetation, and gathering sticks before they find a mate. Once one successfully courts a female, she will build the majority of the nest by arranging the sticks the male has gathered into a shallow bowl 8-12 inches across and a few inches deep before laying 3-5 pale green or blue eggs. Both parents care for the chicks by gathering and bringing them food until they fledge. The young birds occasionally remain with their parents for more than a month after leaving the nest so that they can learn how to hunt before setting off on their own. Once the breeding season is over, many Green Herons will start to move around, sometimes flying great distances to find new hunting grounds, though many birds will stay within a few miles of home until they migrate south for the winter.
Green Herons are among a tiny handful of bird species that are known to use tools. When hunting, they have been observed dropping small fruits, leaf bits, feathers, earthworms, and other small objects onto the surface of the water to act as fishing lures. When a fish comes to investigate, the bird will snatch it up.
These gorgeous birds are a fairly common sight at Prairie Ridge during the summer. Scan along the willows and fallen logs at the edges of the pond or in the branches of the trees 8-10 feet above the water and you might see a Green Heron lurking there. You might also see one sitting on the drain near the dam. The Museum ornithologists suspect that the Green Herons are nesting on the grounds, and we have spotted up to five at a time, so you’re almost sure to see one of these spectacular and entertaining birds on your next trip to Prairie Ridge!
What Time is it in Nature is a weekly feature highlighting the current plants, animals, and other wildlife at the Musuem’s public outdoor facility, Prairie Ridge Ecostation. Find out more about the natural happenings at Prairie Ridge at our What Time is it in Nature Archive!
Photo by Chris Goforth.