Starting in late February and continuing through March, Evanstonians in parking lots, parks, school yards, back yards, anyplace out in the open, may be seen craning their necks skyward, scanning for the source of a loud, an almost prehistoric-sounding “rattle.” Their reward will be the sight of a flock of migrating sandhill cranes, large, long-necked birds, heads pointing slightly downward, long legs trailing behind, calling as they fly. A viewer who has never seen sandhill cranes migrating may be forgiven for suspecting a flock of geese, but careful observation will reveal that this flock looks and sounds nothing like honking geese that fly in a tight, regimental V-formation. Because their calls can be heard for several miles and the birds migrate high, the cranes seem to appear overhead out of nowhere. The best time to look is around noon through 4 p.m.
Sandhill cranes have an ancient lineage. According to the International Crane Foundation in Wisconsin, “A Miocene crane fossil, thought to be about ten million years old, was found in Nebraska and is structurally identical to the modern Sandhill crane, making it the oldest known bird species still surviving!” Sandhill cranes are the most numerous and wide-ranging of the 15 crane species in the world.
Sandhill cranes are big birds. The species that migrates over Chicago is the eastern subspecies of the Greater Sandhill Crane. Standing 4 to 5 feet tall, weighing between 10 and 15 pounds, they have a wingspan of about 7 feet. Males and females look alike, although males are larger. Their feet are the size of a human hand. Their feathers are grey, but when preening, birds will “paint” themselves with the red clay from the iron-rich muddy wetlands where they feed, taking on a rusty color.
Sandhill cranes are birds of open, freshwater wetlands and nearby open fields where grain is readily available. They are omnivores and will poke their long bills in the soil or water for waste grain, tubers, roots, insects, grubs and small mammals.
They migrate during the day. As spring approaches, clear skies and south-eastern winds stimulate the flocks to head north to breed. They fly over greater Chicago from their wintering grounds in eastern Tennessee, Georgia, Alabama and Florida and even in southern Illinois, to their breeding grounds in northern Illinois, Wisconsin, Minnesota, Michigan and southwestern Ontario. Sandhill cranes are faithful to their breeding and wintering grounds.
One of their favorite rest stops in both directions is Jasper-Pulaski Fish and Wildlife Area, 8,062 acres of wetland, upland and woodland game habitat, located in northwest Indiana approximately two hours from Chicago. The area is set up for public viewing of the huge flocks of birds (and large numbers of crane-watchers) that congregate there. As of mid-February, sandhill cranes have already begun arriving at Jasper Pulaski and will be gone by the first of April. Because the birds are in a hurry to get to their breeding grounds, spring concentrations are much smaller than in fall. Mid-November is the best time to visit Jasper Pulaski. On Nov. 27, 2012, observers counted 28,126 cranes there.
Sandhill cranes mate for life, and families migrate and stay together for about 10 months. One of the charming characteristics of the sandhill crane is its dance. While the behavior is usually associated with courtship, cranes can break into dance at any time of the year. The website EEK!- Critter Corner describes the ballet: “The dance looks like two marionette puppets frolicking delicately on strings. They alternately bow and leap into the air with wings stretched out as they circle each other. While they dance, the pair lets out a series of loud calls. The male utters a note followed quickly by the female’s two-note answer.”
Most sandhill cranes will breed at about 4 years of age, once they are paired and on territory. Breeding territory can cover up to 200 acres. Nest building is a fascinating affair. According to the U.S. Geological Survey, both sexes “select a secluded spot within their territory and unison call from that spot. Walking away from that selected spot, they toss nesting materials (mainly the stems and leaves of sedges, cattails, and other wetland plants) behind them over their shoulders. They return to the nest site and pull in the materials within their reach before walking slowly away from the nest and throwing additional materials behind them. As they repeat this sequence many times, large quantities of nesting material accumulate at the low platform nest, while a “moat” of water forms around the platform.”
The hen lays two eggs, but usually only one fledgling makes it to adulthood. Both parents incubate the eggs, for about a month, and both care for the young. The young can walk away from the nest when 24 hours old. According to the Ohio Division of Wildlife, “the older chick is more aggressive…and the two must be separated by the parents. The parents will split up and walk in separate directions so that one chick will follow one parent and the other child the other parent.” The young have grey feathers on their heads, but after their first molt, their heads take on the strange pre-historic-looking characteristics of the adult: bare, scarlet densely-pimpled skin with very short, black bristly sorts of feathers on
The sight and sound of these migrating prehistoric-looking ancient birds inspires awe, once again, in the wonders of the natural world. During March, and again in November, the key is to Listen, Stop, Look Up.