Worry About Whoopers
Efforts to save North America’s biggest bird from extinction
When the world’s last remaining flock of wild whooping cranes set off on its migration south from the nesting grounds on the Alberta/Northwest Territories border last fall, wildlife biologists on both sides of the border were upbeat about how the 4,000-kilometre flight to Texas would turn out.
Unlike 20 of the most common birds in North America that have experienced a decline of more than 50 per cent in the past four decades, whooping crane numbers have been rising slowly but steadily, thanks to an international effort to bring back North America’s biggest bird from the brink of extinction.
In 1945, there were just 15 whoopers remaining in the wild. Last summer, the flock produced a record-breaking 66 nesting pairs in Canada, giving recovery team biologists hope that as many as 300 birds would show up at the Aransas National Wildlife Refuge before Christmas. But instead of celebrating another milestone, U.S. Fish and Wildlife officials were scratching their heads early in the new year, wondering why 34 of the birds that were in Canada last summer didn’t show up on the salt marshes of the Gulf coast late last fall.
That concern turned to alarm when another 21 birds died over the winter.
The recent discovery of yet another seriously injured bird in late March means one-fifth of the population has perished in the last 12 months. What’s more, U.S. Geological Survey researchers have identified the presence of a wasting disease in the endangered flock for the first time.
“We’ve had bad years in the past,” says Tom Stehn, the U.S. co-ordinator of the whooping crane recovery program.
“But in the 26 years that I’ve been involved in this effort, this is easily the worst year I’ve seen. I kind of feel like an aging sports star who should have packed it in after so many good years of playing. We’ve really had a great run and I was feeling pretty good about the idea of retiring in a year or two. This is not how I want to go out.”
Much as Stehn would like to think otherwise, the bad news may not be over. Many of the whoopers that are now beginning to fly north to Canada are not in good physical shape.
While Stehn is optimistic they will make it, he suspects that as many as 40 per cent of those that nested last year won’t lay eggs this time around. “The females likely won’t have the strength to go without food sitting on a nest for 28 or 29 days,” he says. “They really are not in good condition.”
No one knows what happened to the birds that didn’t make it south this year. Power lines, predators and to a lesser extent, illegal hunting, have taken their toll on the whooping cranes in the past. But most of the deaths in Texas this year are linked to a protracted drought at Aransas that has resulted in a severe shortage of blue crabs, which are key to the whoopers’ beefing up for the breeding season.
“Crabs need fresh water to produce,” says Aransas refuge project leader Dan Alonzo. “If the water’s too salty, they quite simply shrivel up and die. So they’re smart enough to migrate out of the marsh when it gets hyper saline during droughts.”
Blue crabs were in such short supply this year that the U.S. Fish and Wildlife Service took the extraordinary measure of feeding the birds corn. That hasn’t been done since the crane was put on the endangered species list in 1971.
“Feeding them corn raised a lot of eyebrows because we don’t normally do that kind of thing in our national refuges,” says Stehn. “But given the situation we were in, we didn’t have a lot of alternatives. It would have been nice to feed them crabs, but how do you do that over an area as big as this?”
Aransas refuge staff also made extra efforts this winter to enforce a long-standing regulation that prohibits commercial crabbing in the 46,000-hectare refuge. In the end, 411 traps were seized and confiscated.
At 1.5 metres tall and 7.5 kilograms in weight, the whooping crane is North America’s largest bird. It is one of 15 species of cranes found worldwide and the only one other than the more common sandhill crane found on this continent. A member of the family Gruidae, Grus americana is more closely related to rails and coots than it is to whistling swans, egrets and great blue herons, which it superficially resembles. It gets its name for the distinctive “whoop” it sometimes makes.
Vulnerable as they are as a species, these cranes are nevertheless a formidable force in the wild. An adult has a wing span as wide as the front end of a Hummer. And strategically positioned, the sharp beak of a whooper is sometimes all that is required to ward off a coyote or bobcat.
They have a voracious appetite and will eat just about anything that comes their way. Biologists have seen them consuming grains, acorns, berries, insect larvae, snails, frogs, clams, crabs, fish, mice, ducklings and even half-grown bitterns.
There is almost nothing that crawls, swims or slithers that they won’t eat.
A creature of wetlands, the whooping crane has always been vulnerable to droughts that have routinely cycled through the southwest, even before climate change became the force it is today.
In fact, biologists believe that drought, more than anything else, was responsible for a decline in the population that began before the U.S. Civil War started.
Be that as it may have been, climate change, agriculture, urban development and the draining of coastal wetlands in recent decades haven’t helped the recovery efforts that got started in 1937 when U.S. President Franklin D. Roosevelt signed the executive order formalizing the original purchase of 20,000 hectares of whooping crane habitat at Aransas.
Biologists believe there were just 29 birds remaining then; 18 in Aransas and 11 in neighbouring Louisiana.
Even when birds of all kinds were being routinely shot out of the air back then, people on both sides of the border were keen to help the whooping crane.
But attempts by the U.S. government and the National Audubon Society to stage a recovery on the southern side of the border seemed to be doomed from the start. In 1940, a hurricane-force storm killed half the birds in Louisiana and scattered the rest.
In the ensuring years, they worked with government departments, schools, naturalist clubs and hunting organizations in an effort to find, conserve and protect what few birds remained in the wild. Leading a parallel effort in Canada were biologist Robert Smith and Fred G. Bard, the director of the Saskatchewan Museum of Natural History.
But win or lose, Kuyt says, the whoopers have become a symbol for the need for an international approach to conservation issues.
© Copyright (c) Canwest News Service
