Originally published on www.critters360.com
The great blue heron is the most widespread and best-known heron in North America. It is most commonly seen wading in wetlands. When observed standing perfectly motionless for several minutes with long neck outstretched, or stealthily walking in shallow water, one has to admire its patient hunting habits. An iconic symbol of healthy wetlands, the great blue heron is the largest member of its family in North America.
Appearance and Coloration
This large bird may stand about four feet tall, with an average length of 42 to 52 inches. With a wingspan of 5 to 6 feet, its wing beats are slow and regular. It rarely soars or glides except just prior to landing in shallow water or in a tree or large shrub. This heron is seen in flight almost anywhere, especially near dawn and dusk, as its favorite feeding areas are often miles away from its nest. Shortly before sunset from April to October, it is frequently seen flying over my urban neighborhood on its way from the Mohawk River to nesting areas several miles away
As it flies, the heron pulls its head back towards its body forming an S with its neck. The long legs extend straight out from its short tail. Because of its size and deliberate wing beats, it is easily recognizable in flight.
This graceful bird with the Latin name of Arde herodius belongs to the Family Ardeidae. There are 59 species of this family of long legged wading birds world wide, 12 of which occur in eastern North America. Common names include crane and blue crane.
In general, the great blue heron appears gray to pale blue in coloration. There is white on the forehead and top of the head, with black on the sides of the crown and crest. There are gray to black plumes extending from the back of the head. The neck is pale gray. There is usually a black patch at the shoulders, with a slate-bluish cast to its upper body and tail. The abdomen is black and white with some rufous streaks. The long, dagger shaped bill is generally an orange-yellow, with dark streaks at the edges. Its eye is usually a bright chrome yellow.
During courtship and early breeding season, the great blue heron undergoes several changes in coloration. The lores, a facial area between the bill and the eyes, are normally gray-green; they change to blue at this time. The plumes forming a crest from the back of the head become more pronounced. The heronâ€™s legs change color as well, from a dusky black to a dark shade of salmon.
The young differ in coloration from the adult. They have no lengthened feathers or crest on the head, and the crown is largely black. The body is more of a brownish slate above with rufous edges, and somewhat ashy gray on the abdomen.
Range of the Great Blue Heron
This large heron extends in the summer over much of the lower 48 states into the southern third of Canada and along the Alaskan coast. In winter, it contracts its range to the southern half of the U.S. and into the West Indies, Panama, and Venezuela. As a water loving bird, it is generally absent from dry desert areas and the cold of the far north.
Nesting Habits and Raising Young
The great blue heron is a solitary bird, especially when hunting. However, it usually nests in colonies of a few dozen up to 150 or more nests. These may be mixed with nests of other species of herons. The female usually constructs the large nest with materials gathered by the male. The nest is usually made with sticks, twigs, and dry grasses, lined with leaves and perhaps pine needles. Usually the nest is 20 to 60 feet off the ground or water in tall trees, though occasionally in lower shrubs. As they often nest in the same area for many years, as existing nests are added to, they can become very large. On the west coast blue herons may nest on rocky cliffs
At two day intervals, the female lays two to seven pale blue or bluish green oval eggs, about 2 and 1/2 inches in size. The first bird hatched is often much larger than those that hatch later, and thus much more likely to survive the first year, especially if food is scarce.
The incubation is by both sexes, lasting about 25 to 30 days. The young are semi-altricial, that is, not totally helpless. They remain in the nest for about 60 to 90 days. One brood is usual in their northern range, while in southern areas there may be two broods.
Both parents feed the young birds. This is accomplished mainly by regurgitation from the adult. At first, the adult will place the regurgitated food right in the youngâ€™s open mouth. As they grow larger, the young will start to actively take it from the adult. In the latest stages prior to fledging, the adult may leave a whole speared fish for the young to feed on while they resume hunting.
The Utica Marsh and the Montezuma National Wildlife Refuge
Most of my heron observations have been at the Utica Marsh. This is a 213-acre wetland straddling the Mohawk River and the New York State Barge Canal, not far from downtown Utica, New York. The New York State Department of Environmental Conservation (DEC) is responsible for management of this refuge.
The Utica Marsh is bisected by a railroad track on a ridge several feet above water level. There is also a deck and an observation tower from which one can view wide sections of marsh with some elevation. From this tower one may sometimes observe four or five herons at a time, feeding alone in various sections of the marsh, well separated from each other.
Another location to watch herons and many other marsh birds is at Montezuma National Wildlife Refuge (NWR). This refuge of over 8,000 acres is on the northern end of Cayuga Lake near Seneca Falls, New York. It is one refuge of an extensive network of NWR sites around the country. At this wildlife management area is a gravel road where in places one can drive slowly at the edge of reed beds for much closer views of herons than is usually possible on foot.
Hunting and Feeding Habits
Great Blue Herons most commonly feed in wetlands. Their long legs are ideal for wading in water a few inches to a couple of feet deep. In this environment their diet consists mostly of frogs, craw-fish, snails, salamanders, and fish. They also eat grasshoppers, and occasionally turtles, and smaller birds.
Sometimes they may be found in drier fields, where ground squirrels, mice and toads are taken as food. Most heron species digest their food rapidly, and they tend to gorge themselves when food is readily available.
Except at nesting colony sites, the great blue heron is largely solitary, especially in its hunting and feeding habits. Quite often only one bird is seen. If more than one bird is observed, they are usually several dozen yards apart, feeding in separate marsh pools divided by hillocks of large reeds or stands of shrubs.
This heron is often seen standing perfectly still for long periods of time with its neck outstretched vertically into the air. Then ever so slowly, the neck will contract towards the body into a curved S. With lightening speed, the bill darts into the water, and a frog or fish is caught. If the prey is large, it is often speared. The bird instinctively knows the extent of its reach, and seldom misses its mark.
At other times, the bird may walk ever so slowly carefully moving one foot, raising it out of the water, and entering the water again without leaving a ripple. This stealthy walk may cover only a few feet over several minutes. There may then be a short pause before the neck quickly stretches out towards its prey.
Smaller prey are immediately swallowed whole. Larger fish are speared, and if especially active, stabbed several times while on the ground. Then the prey is tossed in the air and swallowed whole. Sometimes one is fortunate enough to see the lump of a large frog or fish slide ever so slowly down the heronâ€™s outstretched neck with the bill pointed straight upwards. They have been known to choke to death trying to swallow prey that is too large.
Except when in the colony of nesting birds where croaking and squawking of many birds may be raucous, the great blue heron is mostly silent. It has no real song worthy of the name. It is quite reclusive and skittish around humans, and easily spooked. Chances are that when a person wanders along the wooded edge of a suitable feeding habitat, the bird will fly off with a loud, deep, very unmusical squawk or croak, often before being observed visually. Due to its sensitivity to intruders, the great blue heron is not easy to observe with any regularity at close range. It can be seen in flight, however, almost anywhere, especially at dawn and dusk.
The best places to watch most herons and waterfowl for any length of time is from an observation deck or tower at the edge of wetlands. Unless one is very quiet and stealthy, like the bird itself when in its hunting mode, one is lucky to get a close view. Birds seen from the edge of a wetland are generally 100 to 300 yards away. Binoculars or a spotting scope are necessary to make detailed observations.
At Montezuma NWR, one can drive very slowly, and park momentarily in places perhaps 30 yards away from an edging of reeds, and see these magnificent birds at close range as they feed at the edge of a marsh near the road. The birds have become accustomed to slow moving cars and are not so easily spooked.
If one goes to a suitable habitat of wetlands or open marsh, take a good set of binoculars or a spotting scope. One will find that with a little patience this large member of the heron family is fascinating to watch.
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Netherton, John. At the Waterâ€™s Edge: Wading Birds if North Aneruca. Voyageur Press, Inc., Still Water, MN, 1994. ISBN 0-89658-233-7
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Great Backyard Bird Count 2010 Results: Map of Great Blue Heron (February 2010)