Great blue heron is a master fisher in action
I recently watched a masterful fisher in action. As patient as I've ever observed, persistent as they come, methodical in its approach -- precise, careful, watchful, and silent. But above all, the fisher was an expert that I felt privileged to see.
Indeed, the great blue heron is one of those birds that you can't help but appreciate. Though somewhat gangly in appearance, the bird is graceful in flight, beautifully plumaged and remarkably stealthy when hunting for food.
Belonging to the avian order Ciconiiformes, the great blue heron is the largest and heaviest heron in North America. When standing fully erect, a great blue is about four feet tall.
Mature birds weigh anywhere from six to eight pounds and their wingspans are six feet across. Other heron and heron-like birds residing here in Minnesota include the black-crowned night heron, green heron, great egret, American bittern and least bittern.
Ornithologists and birders tend to call herons, their relatives, and the group of birds they belong to as "wading birds." One of their primary methods of hunting for food, whether a bittern, egret, or heron, tends to be by walking slowly, or wading, in shallow areas of a wetland, lake, creek or river searching for prey. Or, they will stand immobile in the water for long periods of time waiting for something edible to come near.
In the case of the great blue heron, favorite foods are small fish, frogs, toads, salamanders, crayfish, snakes, insects, and even small birds and rodents.
A great blue heron is an efficient hunter. I have watched these birds many times stalking the back bays of wetlands and lakes and I'm always amazed at how well they hunt. Slowly, as they stalk the shallows, they will lift a leg and 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 lightening 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. I remember the first time I saw this latter act.
While fishing one evening years ago near Rockville, Minn., I watched a great blue heron flying across the lake in my direction. I was astonished when the bird began slowing its flight and began stretching its legs out below itself. In a not-so-graceful landing, the bird came to a halt, belly first, and floated for several minutes until it apparently felt the need to fly off.
And like many birds, trees offer more than just pleasant places to perch and view their surroundings from. 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. There are also several rookeries around the lake country of Bemidji and Detroit Lakes.
Building nests of sticks in a flat, platform style very high in trees, great blue herons generally lay three to five eggs inside their haphazard structures. 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 usually has a negative effect on vegetation below the nests, including the trees that support the nests. 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 and waterfowl, which fly with their necks stretched out in front of their bodies, 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. The bird will often perch in a similar manner.
The great blue heron that I recently observed fished along a secluded portion of the fast moving flowage between Muskrat Lake and Lake Sallie at Dunton Locks County Park near Detroit Lakes. As I stood on a boulder only a dozen feet away from the bird, I watched in amazement as the heron speared one minnow after another. It was the first time in my life that I was able to get that close to a heron.
Bejeweled in colorful feathers and long ornate plumes gracing its head, neck and back, the great blue heron is a spectacular looking bird, especially during the spring breeding season. Yet no matter what time of year we see them, be they flying or fishing, lucky we are that the great blue heron calls Minnesota its home as we get out and enjoy the great outdoors.
(Klemek is the DNR Area Wildlife Supervisor in Detroit Lakes. You can contact him at firstname.lastname@example.org)