Great Blue Heron: Symbol of the Chesapeake

By Kathy Reshetiloff

Hidden by the morning mist, a stoic bird patiently keeps watch in the river. Standing motionless, it waits for the right moment to strike at fish swimming near its feet. A twig snaps and the once hidden predator reaches, at first rather clumsily, towards the air. Large blue-grey wings waft in the air as the bird flies off, its neck tucked into a tight "S." This is the great blue heron.

The dignified image is emblazoned on magazines, television, clothing and even license plates. Surpassed only by the blue crab as a symbol of the Chesapeake Bay, the great blue heron is the largest and most widely distributed of American herons and probably the most familiar of wading birds. Whether flying majestically overhead or standing motionless at the water's edge, the great blue heron embodies grace and elegance.

Easily distinguished from other herons, the great blue is four feet tall and sports a dark gray body, chestnut thighs, and white crown, cheeks, and throat. Two long, telltale black feathers rise from the black crown stripe. Typical of herons, great blues have a short tail, extremely long legs and neck and a sharp bill. While in flight, its legs trail behind and the bird is kept aloft by powerful wings that can span six feet.

Great blue herons breed across the United States and southern Canada. More than half of the Atlantic coast breeding population nests in the Chesapeake Bay area. Although many herons migrate through the Bay region, great blue herons often remain as year-round residents, flying further south only as water freezes and food is unavailable. These waterbirds hunt silently, cautiously stalking small fish which they swallow head first. They may also eat frogs, salamanders, lizards, snakes, crawfish, small birds, rodents and insects.

Herons form pairs in March and April and primarily breed in colonies, called rookeries, some of which may support hundreds of nesting pairs. In the Chesapeake Bay region, nesting sites include living or dead trees and sometimes bushes. Nests are constructed of sticks and twigs. If not collapsed by winter weather, old nests may be repaired and used year after year. The nest is lined with reeds, mosses and grasses which cushion three to seven eggs.

Eggs hatch after about 28 days, and both parents care for the chicks. The young are initially fed a diet of regurgitated food but eventually eat whole fish dropped into the nest. Juveniles leave the nest after about 60 days and, if they survive their first winter, may live up to 15 years.

In the past, herons and egrets were shot for their feathers, which were used to adorn hats and garments. Because of their size, herons were often the victims of target practice. The slaughter of these birds went relatively unchecked until 1900 when the federal government passed the Lacey Act, which prohibits the foreign and interstate commercial trade of feathers. Greater protection came in 1918 with the Migratory Bird Treaty Act, which prohibits the killing of migratory birds (except for regulated harvesting of game birds and special permitted removal). This act also prohibits the collection of nests, eggs and body parts of migratory birds.

In recent years, great blue herons have had to face new threats. Deterioration of water quality and loss of habitat threatens herons and other waterbirds. Areas of shallow water habitat are destroyed during land development, resulting in the loss of fish and other prey. Toxic chemicals that enter the Bay from runoff and industrial discharges threaten all Bay inhabitants. Although great blue herons currently appear to tolerate low levels of pollutants, these chemicals can move through the food chain, accumulate in the tissues of prey, and may eventually cause reproductive failure of birds including herons.

Care must be taken to preserve nesting sites as well as feeding areas. Known colonies and nesting sites must be protected. To minimize disturbance, nesting sites should be observed from a distance of about 600 feet. Frequently, disturbed herons may abandon their nests or neglect their young.

Presently, Chesapeake Bay watershed is home to relatively stable populations of great blue herons, but we cannot become complacent in our efforts to protect them. Preservation of shallow water habitat, feeding areas and rookeries must remain a priority if we want to enjoy this majestic symbol of the Chesapeake Bay.