The Great Blue Heron (Ardea herodias), a tall wading bird with a distinctive profile in flight, is North America’s largest heron.
A model of patience, the Great Blue Heron fishes for a living, standing silently in the shallows of a stream, farm pond, wetland or lakeshore, waiting for some hapless minnow or sunfish to swim near, then striking with a rapid thrust of its bill.
The Great Blue Heron stands to a height in excess of 50 inches on long, thin legs, with a wingspan of more than 75 inches, resplendent in its distinctive plumage of gray, white and blue feathers, big yellow eyes and knife-like orangish bill.
Great Blue Herons eat mostly fish, but also feed on frogs and salamanders, and occasionally small turtles, water snakes, insects, and even rodents swimming on the surface. They may hunt day or night. (Photo Provided)
When taking to flight, its call is a harsh squawk, and wingbeats are slow, its head hunched back against its shoulders, neck forming an S-shape.
The big birds eat mostly fish, but also feed on frogs and salamanders, and occasionally small turtles, water snakes, insects, and even rodents swimming on the surface. They may hunt day or night.
Distribution in Kentucky
“The Great Blue Heron is found throughout the state, year-round,” said Erin Harper, a migratory bird biologist with the Kentucky Department of Fish and Wildlife Resources. “In recent years populations have been expanding. They are found on almost any body of water but the larger colonies tend to be on major lakes and rivers.”
Kentucky’s largest Great Blue Heron heronry (rookery) is at Sloughs WMA, a 11,111-acre refuge and wildlife management area, six tracts in the Ohio River bottoms, about 10 miles west of Henderson, Kentucky.
A serious population downturn of Great Blue Herons in the 1950s and 60s was linked to residues of chlorinated hydrocarbon pesticides (primarily DDT), working their way up the food chain. DDT was found to be the reason for fragile eggs, poor egg production and low nesting success of several species of waterbirds and raptors (most notably the Bald Eagle), which feed primarily on fish.
Geographic Range
This highly adaptable bird has an extensive range, and is found in all the Lower 48 States, southern Canada, and as far up the Pacific coast as southeastern Alaska.
Northern populations east of Rockies, in the Northern Plains, Great Lakes and New England, are migratory, some going as far south as the Caribbean, Mexico, Central America, and northern South America.
Nesting
Great Blue Herons nest in colonies that can be quite large.
Harper said one colony near Georgetown, Ky., has 30 to 40 nests.
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“We conduct periodic aerial surveys by helicopter to look for nesting colonies, after the start of nesting in late April or May,” said Harper.
Male herons choose the nest site. They display to attract mates by stretching their necks, ruffling neck feathers, and spreading their wings. Sometimes they fly in circles above the chosen nest site.
Nests are usually in trees 20 to 60 feet above the ground near water, a platform of sticks, more than 20 inches wide at first. But, if the same site is used for several consecutive years, the nest may double in size. The male gathers the nesting materials and the female builds the nest.
Typically, a clutch of three to five pale blue eggs is laid, and incubation is by both sexes. Predators of eggs and nestlings include turkey vultures, crows and ravens, raccoons, and red-tailed hawks.
Adult herons, due to their size, have few natural predators, but a few of the larger avian predators have been known to kill both young and adults, including bald eagles.
Eggs hatch in 25 to 30 days, and both parents feed young by regurgitating fish.
Young herons are capable of flight at about 60 days, and depart the nest at about 65 to 90 days.
Population expansion is by colony dispersal, which begins in the late summer, after the young are fledged, when some of the birds in the colony move to new areas.
Art Lander Jr. is outdoors editor for NKyTribune and KyForward. He is a native Kentuckian, a graduate of Western Kentucky University and a life-long hunter, angler, gardener and nature enthusiast. He has worked as a newspaper columnist, magazine journalist and author and is a former staff writer for Kentucky Afield Magazine, editor of the annual Kentucky Hunting & Trapping Guide and Kentucky Spring Hunting Guide, and co-writer of the Kentucky Afield Outdoors newspaper column.
