An island in the Upper Mississippi, not far from downtown Minneapolis, is home to many Great Blue Herons.(Photo courtesy of Stephanie Hemphill)
Some people say robins are the first sign of spring. But there’s another bird that makes a dramatic entry in northern states. The Great Blue Heron soars in to make a nest… and guard it:
Transcript
Some people say robins are the first sign of spring. But there’s another bird that makes a dramatic entry in northern states. The Great Blue Heron soars in to make a nest… and guard it:
On an island in the Upper Mississippi River, a stand of cottonwood trees is silhouetted against a gray sky. The bare branches are festooned with big nests, made of twigs and branches. Next to the nests, like sentinels at the castle gate, stand Great Blue Herons. These birds are four feet tall. More than a hundred of them are claiming their domain in these trees, just upriver from downtown Minneapolis. When one takes off and glides away, its six-foot wing span dwarfs the ducks and songbirds sharing the island.
It’s hard to tell the males from the females because they’re the same blue and gray. Birder Sharon Stiteler is leading me on a tour of this rookery.
“The males arrive first, and they work out who’s going to take which nest. Where you see one bird standing up, that is most likely a male. He’s hanging out there because the other males who are still waiting to attract a female could come by and steal sticks out of his nest to make his nest look better.”
On some nests, you can see females already sitting on pale blue eggs the size of small mangoes. But Stiteler says herons are not always good parents.
“If the chick falls out of the nest and lands on the ground, that chick is toast: the parents will not continue feeding it. And oftentimes you’ll see turkey vultures hanging out at rookeries, and they’re waiting for the young to fall and starve, and then they’ll have a whole bunch of food.”
But at least on this island, there won’t be many predators like coyotes or foxes.
These birds were once threatened by humans. Their cousins the egrets were hunted for their beautiful white feathers, and both suffered disastrous population loss until the pesticide DDT was banned.
Now you can see them in streams and lakes all over. They breed in Canada and the upper midwest. They spend their winters wherever they can find food. Herons literally stalk their prey.
“They have a lot of patience, and they just stare at one spot for long time, and then they jab down and grab the fish. Their beak is shaped like a pair of super-sharp chopsticks. Sometimes they catch a huge fish and they have to juggle it around, especially if they have it perpendicular with their beak, they have to jostle it around, and the fish is wiggling, and eventually they get it just right so it’s straight in line with the bill, and you can watch this huge thing slide down that long slender neck.”
Sharon Stiteler is a part-time naturalist with the National Park Service, and she writes a blog called bird-chick-dot-com.
Today the herons are pretty quiet. But Stiteler has a Blackberry loaded with their sounds, including the prehistoric squawk they make when they’re startled.
And Stiteler says it can sound really strange when the young are clattering for food.
After the young are raised — at least the ones that survive — the herons will stay here on the river, until it freezes over and they can’t fish anymore. Stiteler says the birds decamp all at once.
“One day we have Great Blue Herons, and the next day they’re gone, and they migrate at night.”
They tuck back their long necks when they fly, forming an S-shape and hiding their true length.
Stiteler says the recovery of Great Blue Herons, along with pelicans, eagles, and other birds near the top of the food chain is a sign of a healthier ecosystem.
For The Environment Report, I’m Stephanie Hemphill.
