D e s e r t E x p o s u r e
August 2009
Wild Blue Yonder
Hundreds of miles from the nearest coastline, the Great Blue Heron can nonetheless be seen in the desert Southwest.
Story and photos by Jay W. Sharp
"The Great Blue Heron," said George Gladden in the 1936 edition of Birds of America, "is the largest of the truly American herons, and is known as a stately, dignified, and interesting bird by those who have observed it in other ways than over the sights of a shotgun or rifle." The long-necked, long-legged and elegant bird often fell to hunters who believed it "to be even more destructive to the spawn and young of game fish than to its other prey of frogs, crawfish, small snakes, salamanders and various water creatures which are more harmful than useful, not to mention grasshoppers and meadow mice." (The Great Blue Heron is now protected under the Lacey Act and the United States Migratory Bird Treaty Act.)
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An adult Great Blue Heron finds a
welcome patch of water in southwest New Mexico. (Photo by Jay W. Sharp) |
In the estuarine waters of the Texas Gulf Coast, where my family and I lived for nearly two decades, the Great Blue Herons stalked the estuarine shallows with a regal air and great patience. They drove their rapier-like bills into the water to take prey with sudden and lethal swiftness. They built colonies of several stick nests in the water oaks and other trees of the dense hardwood forests along the shorelines. They complained loudly, in a hoarse kraak, kraak, kraak, if we disturbed them.
In the deserts of the Southwest, where we have lived now for more than a quarter of a century, the Great Blue Herons came as a surprise to us. A major waterbird in the desert, hundreds of miles from either the Gulf or Pacific coasts? Yet, here they are, stalking riverine environments, lakes and man-made ponds with a regal air and great patience.
According to the Audubon Society's Master Guide to Birding, the Great Blue Heron (called Ardea herodias by biological scientists) stands about four feet tall with a wingspan of seven feet. The largest of our herons, it weighs about 4.5 to 5.5 pounds. (By comparison, our stockier bald eagle has a wingspan of about seven feet and weighs about 10 to 14 pounds.)
"The adult [Great Blue Heron] has a white head with the sides of the crown and nape black, and short plumes projecting to the rear," the Audubon guide advises. "The neck is light gray, with a whitish ventral stripe; the bill is large and yellowish; the body is blue-gray, and the legs are dark." Sometimes, the heron's belly tends toward white with dark stripes. The iris of its eye has a distinctive yellowish gold color. The juvenile Great Blue Heron lacks the trailing plume on the back of its head.
Like a crane, the Great Blue Heron flies with slow, swooping wing beats, its legs trailing, and it walks with long and deliberate strides. Unlike a crane, which flies with its neck extended, the Great Blue Heron flies with its neck folded into an "S" shape, its head almost resting on its shoulders. In flight, the bird's body seems disproportionately small compared to its wings. "When the heron takes to flight, what a change in size and appearance!" wrote Henry David Thoreau (Thoreau on Birds). "There go two great undulating wings pinned together, but the body and neck must have been left behind somewhere."
If the Great Blue Heron survives its first 12 months, when it is most vulnerable to predators, bad weather and food shortages, it may live 15 years. With very good luck, it can live for more than 20 years. The bird does seem to be accident prone, sometimes flying unwittingly, and fatally, into power lines or fences.
Probably the best known and perhaps the most adaptable of all the herons, the Great Blue Heron covers a range that extends from southern Alaska and southern Canada southward across the entire contiguous United States and into Mexico, Central America, northern Colombia and Venezuela, the Caribbean Islands and even the Galapagos Islands. Migratory populations breed in southern Canada and the upper Midwest, and they winter in Mexico, Central America and northern Colombia and Venezuela. Year-round, or non-migratory, populations span most of the lower United States, from the Atlantic to the Pacific, including most of the desert Southwest. The Great Blue Heron occurs across southwestern New Mexico except for the Bootheel.
The birds claim fishing territories in the calm shallows of permanent water sources, including, in the Southwest, the Colorado River and the Rio Grande and their tributaries, the mountain springs and streams, the riverine marshes, and the impoundments. Typically, they build nests in trees and shrubs near the water's edge, up to about 5,000 feet in elevation, usually as part of a colony called a heronry or a rookerie.
While perfectly willing to raise a family in the company of others, the Great Blue Heron prefers to pursue its passion, fishing, in solitude and with single-minded purpose. It guards its fishing territory jealously. Locating its prey by sight, the bird may fish through the night and the day, although it intensifies its hunt at dawn and sunset, typically the most promising time of day for all species of anglers.
According to the Hinterland Who's Who website, the Great Blue Heron, when fishing, may stand as if frozen in the water, furtively moving only its head and eyes. "When a potential meal comes close enough, the heron slowly folds its neck back and moves one leg in the direction of the prey. Suddenly, its entire body unbends, its head plunges into the water, it catches the prey in its bill, and it swallows it outside the water, using a deft movement of the head to drop the prey headfirst into its gullet."
Alternatively, the bird may stalk prey, driving fish from hiding. "The great bird may be seen stalking slowly through shallow water, lifting each foot above the surface, and sliding it into the water again so gently as to cause hardly a ripple," wrote Gladden, "and woe to the crawfish or salamander that does not observe that approach." In other instances, the bird may drop from a streamside perch or even from flight into the water to take its prey.
Usually, the Great Blue Heron takes small fish, which measure less than the length of its bill. Occasionally, however, the bird gets greedy, taking a fish too large to swallow. It may even choke to death on its prey.
In addition to fish, the adaptable Great Blue Heron often eats frogs, shellfish, insects, rodents and even small birds. In some instances, it feeds nestlings a diet with a high percentage of rodents.
At about two years of age, the Great Blue Heron — normally as reserved as the queen of England — discovers sex, and the male, especially, can become a perfect showoff. Just as with the species we call Homo sapiens, "the male begins to display, attracting females, but repelling them," according to the Illinois Department of Natural Resources.
Come spring, the sexually mature male chooses a tree for a nesting spot, a site he will guard ferociously. When females come near, males put on impressive displays while shrieking loudly. Getting acquainted, the male and female crack their bills together tenderly. They court with elaborate body movements around the potential nest, much as Homo sapiens court with strange-looking movements on a dance floor.
If the feathered lovers bond, they promptly mate for the first time. The male then begins gathering dead twigs, which his bride will use to build a nest several feet in diameter, sometimes lining the cavity with moss or pine needles. "As a male heron with a twig returns to the nest," according to the Utah Division of Wildlife Resources, "he is greeted by his mate with a 'stretch' display. In this display a [female] heron stretches its neck outward and points its bill upwards in an arc while lowering its body by flexing its legs. An 'aarrooo' vocalization accompanies the display. . . . The feathers are fluffed and back and chest plumes are raised."