Whooping Cranes: Grus americana
Whooping cranes, the tallest of North American birds, stand nearly 5 feet tall. Their wingspan measures between 7 and 8 feet. Males weigh 16 pounds and females weigh 14 pounds.
Initially, chicks are the color of cinnamon brown. By four months of age the chicks have emerging white, adult-like feathers that produce a mottled appearance. Young whooping cranes achieve adult-looking plumage as they approach one year of age.
The average nesting territory for a pair of whooping cranes in Wood Buffalo National Park, located in Canada's Northwest Territory, is 1,013 acres.
The only remaining whooping crane natural population nests in Wood Buffalo National Park where the bird spends its summers. The whooping crane winters at the Aransas National Wildlife Refuge (NWR) on the Texas gulf coast. Whooping cranes were once found over most of North America - from the arctic to central Mexico and from the mid-Atlantic coast and New England to Utah, Wyoming, and New Mexico. A flock of non-migratory (resident) birds persisted in southwestern Louisiana until the late 1940s. The Fish and Wildlife Conservation Commission (FWC) has been involved with establishing non-migratory and migratory flocks of whooping cranes in Florida. Due to a number of problems, no further releases will be made into the non-migratory flock.
Whooping cranes rely on shallow marshes and adjacent, open grasslands.
Whooping cranes eat aquatic invertebrates (insects, crustaceans, and mollusks), small vertebrates (fish, reptiles, amphibians, birds, and mammals), roots, acorns, and berries.
The nesting season in Wood Buffalo National Park begins in late April or early May. In central Florida it begins in January and extends through May.
Mean clutch size, or number of eggs per nest, is 1.94 eggs. Most nests contain two eggs; occasionally, nests contain only one egg, and rarely three.
It takes between 29 and 31 days for the eggs to hatch. Both males and females incubate. A whooping crane pair will renest if the first clutch of eggs is destroyed before mid-incubation.
One chick is most common. Whooping cranes rarely succeed in raising two chicks.
Young whooping cranes are capable of flight when they are between 80- and 90-days old.
Young migratory whooping cranes become independent from their parents during northward migration or shortly after arrival on the breeding grounds. For non-migratory whooping cranes in Florida, young whooping cranes become independent just before the parents begin their next nesting season.
Whooping cranes produce their first fertile eggs between ages 4 and 7 (mean = 5.4 years).
Whooping cranes mate for life, but they will take a new mate after the loss of the original. The pair will return to use and defend the same nesting and wintering territory year after year.
They are known to live at least 22 years in the wild and perhaps as long as 40 years.
The world's whooping crane population has gradually increased from a low of 22 birds in 1941 to 503 birds in spring 2009. Always rare, the whooping crane population may never have exceeded 10,000.
During the nineteenth and early twentieth centuries, whooping crane habitat was lost to agriculture and drainage, and humans hunted the birds and collected their eggs - all of which contributed to the population decline. While Wood Buffalo National Park was established in 1922, it wasn't until 1955 that it was discovered that whooping cranes nested there. The Aransas National Wildlife Refuge (their principle wintering site), located in Texas, was established in 1937. Captive propagation, or breeding, initiated at the Patuxent Wildlife Research Center in Maryland in 1967 produced the first captive-produced eggs in 1975.
For whooping cranes to be "down-listed" from endangered to threatened status, there must be 40 nesting pairs in the Aransas/Wood Buffalo Park population and 25 nesting pairs in two additional locations, or 100 nesting pairs in the Aransas/Wood Buffalo Park population and 30 nesting pairs in one additional location. The migratory flock of whooping cranes in Florida is being introduced to achieve that goal.