Nachusa's Sandhill Cranes

By Charles Larry
Nachusa Volunteer

A sandhill crane trumpets at the wetland.

The sound of the sandhill crane seems to echo across an immense gulf of antiquity. Cranes evolved during the Eocene (56-33.9 million years ago). The earth was warmer and wetter during this time, and in North America, with vast areas of prairie, savanna, marsh, and shallow inland seas, it was ideal habitat for the ancient ancestors of modern cranes. This early crane was likely a relative of the crowned crane now found in Africa. Fossil remains of this early crane have been found in North America, dating some 10 million years. But then the climate in North America started to cool, eventually bringing about the Ice Ages. These events saw the disappearance of this early crane on the continent. At some point a relative of the modern crane, one suited for cooler climates, evolved here. The earliest fossil of this later crane was a bone almost identical to that found in modern sandhills. This fossil was found in Florida, dating back 2.5 million years. Modern sandhill cranes (Grus canadensis) are divided among two and six geographical subspecies, depending on sources. Generally, there are the greater and lesser sandhills. 

Two adult sandhill cranes.

Nachusa Grasslands has had sandhill cranes stop over for brief periods over several years. In August of 2018, even a pair of whooping cranes stopped and then moved on! As far as is known, this is the first time that a pair of sandhills have nested and raised two colts (as the young sandhills are called) at Nachusa. It is usual for sandhill cranes to lay two eggs, a few days to a week apart, but it is rare that both colts will live to fledge. Some reasons as to why only one colt survives are various predators, lack of sufficient food, and sometimes the aggression of the older crane toward its slightly younger sibling. At Nachusa both of the young have fledged and are flying. 

Two adult sandhills and two very young colts.

Sandhill cranes usually mate for life. They become sexually mature at two years old but four or five years old is more likely to be when mating begins. Sandhills are well known for their "dancing" during mating season. This behavior is not fully understood, as cranes of any age may dance at times not related to breeding season. It is thought to also be a way of working off aggression. 

A juvenile sandhill dances.

Both sexes participate in the building of the nest, constructed in or near water. Nests are composed of plant material found near the nesting site, such as cattails, sedges, rushes, and grasses. 

An adult among cattails.

Nests can be six feet in diameter. At breeding time both sexes "paint" their feathers with clay and mud. The birds are normally gray in color, but the painting changes the feathers to brown. This is thought to be a camouflaging technique to blend in with the nesting site. 

The adults after "painting." The gray coloration of the neck and head are the crane's true color.

Both parents incubate the eggs. While one sits on the nest, the other is either standing guard or gathering food. The female usually sits on the nest during the night. Hatching is about a month after laying. After hatching, the cranes abandon the nesting site, moving to a hidden spot somewhere still near water.

The parents are fiercely protective of the young. Many predators are a danger to either the eggs or the colts. Among them are coyotes, foxes, raccoons, owls, and various hawks, all of which inhabit Nachusa Grasslands.

Red-winged blackbirds hassle the crane family. Predators: great horned owl, raccoon, coyote.

Sandhills eat a variety of food, from insects such as grasshoppers or dragonflies, to aquatic plants and tubers, to small mammals such as mice, to snakes and worms. They will even eat the eggs of other birds, such as red-winged blackbirds, rails, and ducks. More recently, sandhills have learned to forage in cornfields and will often flock in vast numbers doing this. During breeding season, they are very territorial with an average territory range of about 20 acres. Until the cranes abandon the nesting site, where they are more or less isolated, they will defend this territory from other sandhills and predators by various aggressive displays and even fighting. 

An adult and two colts eating plant material.

By late summer the sandhills will probably move to an area where there is a larger crane population and more abundant food to fatten up for migration, which will happen sometime in the fall. The juveniles will stay with the parents during migration and through the winter. Sometime in the following spring they will separate from their parents and go out on their own. The main winter flyways for migration in this area are either south to Georgia or Florida or over to Texas. 

The cranes prepare to fly.

Sandhill cranes are threatened, as is true of cranes the world over. Climate change is one major threat. Droughts have become much more frequent, and wetlands are disappearing. In some states cranes are hunted. In the past, this resulted in the extinction of sandhills from Washington State in 1941. They have now been reintroduced to this state in small numbers. Farming conversion to incompatible crops (soybeans) over crops like corn also threatens cranes. Probably the biggest threat is from loss of habitat from urbanization and development.

The sandhill crane is a magnificent bird. It would be tremendously sad if someday the sandhill crane were to join the thousands of species disappearing from our planet. To hear no more the sound of this bird, which author Peter Matthiessen says is "the most ancient of all birds, the oldest living bird species on earth." Sad indeed.

The crane family flying at sunset.

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Sources: 
Johnsgard, Paul A. A Chorus of Cranes: the Cranes of North America and the World. 
University of Colorado Press, 2015.

Forsberg, Michael. On Ancient Wings. University of Nebraska Press, 2004.

Matthiessen, Peter. The Birds of Heaven, North Point Press, 2001​.

Useful websites:

• International Crane Foundation
• Cornell Lab of Ornithology
• National Audubon Society​

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If you would like to play a part in habitat restoration for sandhill cranes at Nachusa Grasslands, consider joining our Thursday or Saturday Workdays, or give a donation to the Friends of Nachusa Grasslands. Donations to Friends can be designated to support the ongoing stewardship at Nachusa.

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​Charles Larry ​has been photographing Nachusa since 1994. As a volunteer he served on the social media team that created the Friends of Nachusa Grasslands' website (2015-2018). He and his wife, Emmylou Studier, did Photo Points, a method, through photography, to monitor the restoration process, from 2008-2018. He also maintained the bison exclosure fences for a time (2016-2018). Currently, Charles contributes photos to Nachusa Grasslands, Friends of Nachusa Grasslands, and The Nature Conservancy.