On a spring afternoon some years ago, I beat on my neighbor’s door, wild with excitement. When she answered, looking puzzled, I dragged her outdoors and pointed skyward. “Cranes!” I cried with glee. “A sure sign that spring is here!”
I am convinced she thought I had gone daft. We talked about the circling mass of birds, calling to one another high over our heads. I explained my delight in sandhill cranes, and thanked her for letting me share my joy with her.
Her two obvious questions were, “Where are the cranes headed and why do they call as they fly?” Anyone who has heard that almost prehistoric conversation between flock members begs to ask the same questions.
Sandhill cranes have a number of different subspecies, each using a different migration flyway. Our cranes are part of the mid-continent population. They winter in Texas, New Mexico and southward into Mexico. Their springtime northward migration eventually lands them in the far reaches of the Canadian prairie provinces. Some may head toward Alaska.
They are in search of wet grasslands, marshes and bogs. The more isolated the habitat, the more cranes like it. Their diet is quite diverse. Anything from insects to small mammals, fish and grains will be consumed. The time of year dictates much of the selection, and so cranes make use of just about anything. We associate cranes with croplands, because South Dakota serves as a stop-over on their way to and from their breeding grounds.
The sandhill is a species that mates for life. Typically the only thing that will cause a bird to take another mate is the death of the first. Once they arrive on their breeding grounds, they will begin courtship rituals and breed. A nest can be built either on solid ground or floating on water. It is made of last year’s dried plant material, formed into a cup shape. Nests can get quite large, some over water measuring 4 feet by 3 feet, and 16 inches in height.
Two eggs are laid, usually two days apart. Crane chicks are leaving the nest and begging for food from their parents within 24 hours of hatching. The family bond is strong. Crane families stay together until the youngsters are about 10 months of age, and on the wintering grounds.
The eerie, bugling calls are intended to keep those strong family units together during migration, as well as on feeding and loafing grounds. They can be so loud that they can be heard 2.5 miles away, which also lends credence to the idea that the conversations may unify separate flocks of migrating cranes.
The autumn after my visit with my neighbor, she was the one pounding on MY door. “Do cranes migrate through here in the fall?” she asked. “I’d swear I am hearing cranes!” We stepped out into the late-afternoon sun and listened. Sure enough, our cranes were headed south for the winter.