It's usually by mid-March that we watch for the return of the first great blue herons. Now, we're watching new migrants standing on ice-covered lakes in late April.
Most of them are returning from places such as south Texas, Mexico and Central America, which they departed for in September. Only a few stragglers were seen in the southern part of the state during winter.
Great blue herons are stately, graceful birds, flying with slow, steady wing beats, necks drawn in and legs stretched behind. They stand over 3 feet tall, with much of their height made up of long legs and a long neck. Their wings measure 6 feet from tip to tip. Other distinguishing characteristics, aside from the commanding height and blue-gray color, are the largely white neck and head and 6-inch yellow bill.
Often called the blue crane, the great blue heron is the largest and best known of American herons. They always return to their breeding range, and specifically, to their nesting rookeries, early in the season. Like most of the heron species, they are sociable, preferring to nest in congested communities that vary in size from a few pairs to hundreds of birds. A week ago, a dozen herons were seen standing in individual nests in one eastern cottonwood tree in a rookery next to the Cannon River at Northfield. Now as nesting season begins, the large nests, loosely constructed of sticks, are built up. They are used year after year. Three to five eggs are the norm, and the incubation period is about 28 days. Herons usually feed alone, spreading out from the home rookery. They fly many miles to procure food for their young and themselves. Food includes small fish, frogs, insects and other wildlife.
Many times while vacationing on the shores of beautiful Lake George in Hubbard County, our family has seen a great blue heron standing motionless on a distant point, silhouetted on the shore against the sky. Its artistic outline added a touch of mystique to the broad expanse of water and dark forest. These herons are found throughout most of Minnesota, and some of the largest nesting colonies are found in the southeastern and central regions.
Jim Gilbert's Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.
