image: The Smithsonian's National Zoo has a new addition: Rocky, a male whooping crane (Grus americana). This is the first time the Zoo has exhibited this species in 88 years. Visitors can see Rocky on exhibit at the Zoo’s Bird House and learn about this endangered species, which were reduced to only an estimated 21 individuals in 1938 due to hunting and agricultural expansion. Their population, however, is now on the rise and scientists at the Smithsonian Conservation Biology Institute will also be looking to Rocky to help them determine the impact of genetic diversity on whooping crane sperm quality and fertility rate in captivity. view more
Credit: Mehgan Murphy
After an 88-year-long hiatus North America's tallest bird, the statuesque whooping crane (Grus americana), is once again on exhibit at the Bird House at the Smithsonian's National Zoological Park. An 11-year-old male whooping crane named Rocky left Homosassa Springs State Park in Florida and is now on exhibit in the nation's capital. Whooping cranes are one of only two crane species native to the United States. There are only eight other zoos in the U.S. which exhibit these birds.
"It is an honor for the National Zoo to once again exhibit this magnificent species," said Dennis Kelly, director of the Smithsonian's National Zoological Park. "Although most people have heard of whooping cranes, very few have had the privilege of seeing one in person. We are thrilled to have Rocky here as an ambassador for his species."
Rocky is only the fourth whooping crane to call the National Zoo home. The Zoo's first crane, a wild-caught bird of unknown sex, arrived in 1897. Its last, a female, died in 1923.
By 1938, hunting and agricultural expansion had decimated wild whooping crane populations to an estimated 21 individuals. Zoos, research centers and nature preserves acted quickly to curtail the threat of extinction. Working together, they carefully matched individual birds that did not have mates in order to stabilize populations and achieve the greatest genetic diversity possible—a considerable challenge, given the population bottleneck.
Today, U.S. whooping crane populations are managed by the U.S. Fish and Wildlife Service. According to the 2010 census, 407 whooping cranes reside in breeding centers and protected nature reserves in the eastern and mid-western United States and Canada, while another 167 individuals are in human care. These numbers mean that their population trends are increasing, an encouraging sign that the species will thrive.
"Their remarkable population recovery and subsequent reintroduction is one of the greatest conservation stories in North America," said Ed Bronikowski, senior curator at the National Zoo. "Thanks to the continuing efforts of many, this species is not going extinct anytime soon."
Despite this progress, whooping cranes are still considered endangered by the International Union for Conservation of Nature. In breeding centers and zoos, whooping cranes can live upwards of 40 years old. In protected nature reserves, however, a whooping crane's lifespan is limited to about 30 years. Collisions with fences and power lines, illegal hunting, predators, disease and polluted waterways threaten these cranes.
Visitors can see Rocky in the "Crane Run" exhibit outside of the Bird House. He is 5 feet tall and has a plume of white feathers, save for a patch of red and black feathers between his beak and the nape of his neck. He also has a 7-foot wingspan, which these cranes use to propel themselves 45 miles per hour during flight. Rocky will serve as an educational ambassador for his species, illustrating the behavior of whooping cranes to scientists, keepers and Zoo visitors. However, there is one trait visitors will not see Rocky perform: the loud "whoop" call these birds are named for.
"We don't know why Rocky is mute," says Sara Hallager, biologist at the Zoo's Bird House. "The reason behind his silence is a mystery known only to him."
The Zoo currently has no plans to breed Rocky, but his genes will not go to waste. He will participate in a study by the Zoo's Smithsonian Conservation Biology Institute that determines the impact of genetic diversity on whooping crane sperm quality and fertility rate in captivity.