I’m not sure if I’ve ever been on a river, at any time of year, and not seen a Great Blue Heron. They seem to stand as solitary sentries on the rivers of Montana, but also on rivers from Canada to South America.
In winter I see one standing on one long leg just inside the frozen edge of the river, back to the wind, feathers blowing forward. Their steel-blue feathers are the color of the sky and water that time of year. In spring I see that six-foot wingspan pump in slow motion downstream, legs trailing behind. But it was early last summer that I saw a blue heron’s nest for the very first time.
I was kicked back in my canoe, a leg thrown over each side. My toes put a tiny tear in the surface of the water that ripped wide before being swallowed back into glass. My paddle was stowed. Just downstream I saw a heron in a slow sneak. It gently pulled each leg completely out of the water and placed it back in without seeming to disturb the surface by so much as a drop. With a sudden plunge the heron came up with a small, glistening fish. The heron threw the fish to the back of its throat and I watched the bulge slide down the bird’s long, slender neck.
Shortly after, the heron lifted out of the river, neck tucked, feet trailing, and glided into a nearby tree. As I drifted past, I noticed that there was not just one nest, but eight heron nests in this giant cottonwood tree. I was shocked. I knew the heron as a solitary bird. I could hardly imagine it with a mate or young, but there it was in what looked and sounded like a wild apartment building. The whole tree came alive with chicks as this adult landed beside its nest. The quiet giant of the river lives in a commune.
Great Blue Herons build new nests or reuse ones from previous years. Between March and May, select riverside trees become construction sites. Males make many trips to gather twigs, leaves, moss, pine needles and branches, which they bring back to the females, who do the actual construction. When she’s done, a female tramples her nest to make it stronger and to make the walls of the nest high enough to prevent a chick from falling out. Females then line the inside of the nest with vegetation to cushion the bottom and make it more comfortable. Supposedly, blue heron nests can withstand gale force winds. Great Blue Herons usually try to repair and reuse old nests. And old nests are much bigger than new nests because herons add onto them each year.
Great Blue Herons lay three to seven greenish-blue eggs between the months of July and August. The incubation is about four weeks with both male and female taking turns at keeping the eggs warm. Young are born with their eyes open, no doubt looking at the chicks next door, and are totally dependent on their parents for food. The parents bring back food in their stomachs and regurgitate it to feed their young. Newborns require one quarter of their body weight in food every day. At between two and three months of age, the fledglings are ready to fly. In two years, they’ll be ready to mate and join a commune of their own.
"Field Notes" is produced by the Montana Natural History Center.