Great blue herons are not uncommon in foothills

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By Sylvia Brockner

A reader of this column sent me a message via the Canyon Courier this past week, saying she had seen a great blue heron along North Turkey Creek and was wondering if that was unusual. Yes, it is a bit unusual this early in the season.
Great blue herons are not an uncommon bird. They range across America and nest at Barr Lake and Cherry Creek Reservoir. However, a few years ago, they had declined so that they were blue listed, which means that the decline was serious enough that they were considered a “species of concern,” which needed watching for they might be in serious trouble.
In the past few years and in some parts of its range, it has made a recent comeback and has been removed from the blue list. There is a small colony of these birds nesting at Bear Creek Lake Park, and since both Bear and Turkey Creek flow into the reservoir, it is not unusual to see them along both creeks. However, it is a bit early to see them so far upstream. Usually they feed at the reservoir and along the lower creek until the growing young demand so much food that they begin to deplete the supply. It is usually later in the summer that they move upstream in search of more food.
The great blue heron is our largest and heaviest bird. They stand four feet tall and have a 72-inch wingspan. Their big size and large bills, legs and feet make them heavy, and they always seem as if they are having trouble getting airborne. However, once in the air they are strong, graceful fliers. They almost always call when they take flight, making a loud disgruntled “kraak, kraak, kraak” that has earned them the common name among country folks as “big grumpy.” Great blues are early migrants, and very rarely one will winter in the Denver area whenever there is open water along Clear Creek or the Platte River.
Once they are airborne, great blue herons pull their necks back in an S curve, folding it between their shoulders. All herons do this, while all cranes fly with their necks out straight. Both cranes and herons fly with their long legs sticking out behind them.
Great blue herons do eat a lot of small fish, but they are mostly minnows and less desirable species. They also eat frogs, crayfish and in early spring if the water is still ice covered when they arrive, they will hunt in open meadows for mice.
Great blue herons nest in colonies of anywhere from a few to a hundred or more pairs. Their large stick nests are built in the tops of large trees that are in or near the water. The best place to see these interesting colonial nesters is at Barr Lake or Chatfield Reservoir in the early spring. When available, they prefer to nest in cottonwoods, so the best time to watch the nest building, etc., is in March before the leaves come out. Once the trees have leafed out, it is harder to see the nests.
I doubt that they will ever nest at Evergreen Lake for there are no big old trees along its shores, and there is too much human activity. They do not tolerate any disturbance within 275 yards of the colony, and this seems to be one of the reasons for their decline in the past. Once human activity was restricted within 275 feet of the colony, they continued to nest with no problems. However, they can be seen most every day at Evergreen Lake or in the shallows along Upper Bear Creek. They are most frequently seen on the sandbar at the inlet where their large size becomes most apparent.