Aside from Canada geese, one of the first wetland-associated birds I observed this late spring was the great blue heron. At the time I observed the solitary heron flying gracefully overhead, most wetlands and all of the area lakes were still ice-covered, but rivers and creeks were freely flowing.
Belonging to the avian order Ciconiiformes, the great blue heron is the largest and heaviest heron in North America. Indeed, when standing fully erect, a great blue heron is nearly 4 feet tall and can weigh 6 to 8 pounds. And their wingspan alone is some 6-feet across! Other herons residing here in Minnesota include the black-crowned night heron and the green heron. Additionally, the pure white great egret occurs in the southern half of Minnesota, though generally, during only the spring and autumn migration.
In the case of the great blue heron, favorite foods are small fish, frogs, crayfish and snakes. They will also eat insects and small rodents. A great blue heron is an efficient hunter. Many times I have watched these birds stalking the back bays of wetlands and lakes and am always amazed at how well they hunt. Slowly, almost imperceptibly so, they will lift a leg to step forward. Gingerly, the bird will place that extended foot into the water without making a sound. Then, as its eyes lock onto an unsuspecting fish, the bird moves only its long neck forward and down, thereby directing its head and dagger-like bill toward the surface of the water.
Up to this point the entire act is completed very slowly. The actual strike, however, is anything but. In an action that could be likened to a lightning strike, the heron stabs quickly, often immersing all or part of its entire head into the water. And of all the times I have witnessed the moment of truth between this particular hunter and the hunted, I have never seen the bird come up empty “handed.” A heron will have in its bill a flopping fish, will manipulate the hapless prey for proper placement and will flip it headfirst into its mouth and swallow it whole.
One would think that such a physique would render a great blue heron with limited options of mobility. But really, the big bird can land effortlessly in the limbs of treetops and can even float like a duck in water too deep to wade in.
As is the case for many wild birds, trees offer more than just pleasant places to perch and view their surroundings. Great blue herons are well known for the large nesting colonies they form with others of their kind. Called rookeries, the sociable herons will return year after year to the same nesting site, often arriving to these areas around the same time every year. One such rookery that I became familiar with was a large one located along the Sauk River near Cold Spring, Minn. The large birds would always arrive before the ice was out and tended to take advantage of discarded minnows and small fish that fishermen left on top of the ice.
Building nests of sticks in a flat, platform style very high in trees, great blue herons generally lay three to five eggs. Both parents share incubating duty and hatching occurs in about a month. The problem with these large heron rookeries becomes obvious if you should happen to see one up close. Excrement from so many birds concentrated in a relatively confined area sometimes has a detrimental effect on the vegetation. Many trees die and so the rookery eventually has to be relocated.
It’s easy to identify a great blue heron, both in flight and silhouette. Unlike sandhill cranes, which fly with their necks completely straight, the great blue heron flies with their necks in an “S” shape, giving observers the impression that the bird has hardly any neck at all.
Graced with colorful plumage during the springtime breeding season replete of long, ornate plumes covering its head, lower neck, and back, the great blue heron, despite its dinosaurian appearance, exemplifies matchless beauty and behavioral uniqueness among wild birds anywhere as we get out and enjoy the great outdoors.