Florida Sandhill Crane
The sandhill crane has been split into six subspecies, including two in Florida: the resident Florida sandhill crane
(Grus canadensis pratensis) and the migratory greater sandhill crane (G. c. tabida). The former subspecies nests in Florida, while the latter nests in the Great Lakes region.
The Florida sandhill crane ranges from the Okefenokee Swamp in Georgia south through most of the Florida peninsula. Its population in early 2000 was estimated to be 4,000 birds. The greater sandhill cranes winter in Florida from October through March. These two subspecies can be distinguished only by behavioral differences. The greater sandhill crane is more easily disturbed by human encroachment, and its roosting and feeding flocks are larger than the Florida sandhill crane.
During migration the greater sandhill crane flies in a tight V- or U-shaped flock. The Florida sandhill crane flies in a loose linear flock. Both types of sandhill cranes fly with their legs and neck extended; their wing upstroke is snappy, while the downstroke is slow. In comparison, herons such as the great blue heron have evenly paced downstrokes and upstrokes, and the neck is curled back in flight.
The adult Florida sandhill crane stands 4 feet tall with a 6-foot wingspan. Females and males weigh about 9 and 10.4 pounds, respectively. Both sexes have gray plumage that sometimes is stained a reddish brown. The sandhill crane’s head exhibits white cheeks and a red crown. Juvenile birds have brown necks and heads and achieve adult-like appearances at 10 to 14 months of age.
The best way to determine sex is by listening to the male and female “unison calls.” The male’s voice is lower pitched than the female’s. The female’s call is two to three times shorter in duration than the male’s. A mated pair often duets at dusk and again at dawn from their nest. Sandhill crane calls can be heard two to three miles away.
Adults reach sexual maturity at two to three years but are more likely to have a successful clutch at five years. The nesting season in Florida is from January through June. Nests are 3 feet in diameter and are built 6 to 7 inches above standing water. The eggs are olive brown. Clutch size is normally two eggs, which are incubated by both sexes for 29-32 days. The young hatch a day apart. The hatchlings are precocial (born in an advanced stage of development) and usually leave the nest within 24 hours. Accessory nests are built within 150 feet of the primary nest as daytime rest sites for the young and for brooking hatchlings at night.
The young are capable of flight within 2-2.5 months, and they leave the family unit in 10 months. Home range of an individual sandhill pair averages 1,100 acres. The defended nesting
Sandhill cranes fly with their legs and neck extended; their wing upstroke is snappy, while the downstroke is slow.
territory ranges from 300 acres to 625 acres. Mating productivity is highest during winters with more rainfall, which produces more suitable nesting sites. Productivity is lower in years with high spring rainfall because of nest flooding or because wetlands become unsuitable for nesting.
Shallow wetlands that are 10 to 14 inches deep and dominated by maiden cane and pickerelweed are preferred by the Florida sandhill crane for nesting. It forages in adjacent and essential open uplands and dry prairies, with vegetation mostly 18-20 inches tall. It is also observed in wet prairies, open woodlands, improved pastures, ranchlands, sod farms, suburban subdivisions, airports and golf courses. It feeds on a variety of animals and plants, including seeds, acorns, tubers, roots, corn, peanuts, dewberries, blueberries, mice, rats, small birds, frogs, snakes, dragonflies, crayfish and grasshoppers.
The Florida sandhill crane is listed as a state-threatened species by the Florida Fish and Wildlife Conservation Commission (FWC) because of its low reproductive potential, vulnerability to predation, nonnatural mortality and loss of habitat. Egg predators include fish crows and raccoons. The young and some adults are preyed upon by bobcats, coyotes and many other predators. The young are also preyed upon by free-roaming cats and dogs. Adult non-natural mortality includes diseases, collisions with utility lines, road kills and getting entangled in fences.
Nesting sandhill cranes are sensitive to human encroachment activities, and thus a 400-foot buffer has been recommended by scientists to prevent nest abandonment caused by human disturbance. Everyone should be aware that sandhill cranes are wild animals and can be dangerous during the nesting season.
The Florida sandhill crane prefers to nest in shallow wetlands. This one was photographed at Harns Marsh in eastern Lee County.
Florida sandhill cranes with their young, which are born in an advanced stage of development and usually leave the nest within 24 hours