On the road to recovery
by Traci Miltenberger
NNSL (Aug 04/97) - Two rare birds that call the Northwest Territories home show signs of at least holding their own against 20th-century threats of extinction.
The arctic species of the peregrine falcon, known by its latin name, tundrius, has managed to remove itself this past year from the endangered species list, moving to the less dire "vulnerable" category.
The whooping crane, meanwhile, is still considered endangered, but seems to be holding its own after years of declining populations.
Mark Bradley, a scientist involved with the protection and research into the peregrine falcons, says two of the three species of peregrine falcon are on the upswing but "still are not back up to their historical norms."
In the late 1950s and early 1960s scientists and bird observers began noticing that the falcons were disappearing. It was discovered that the widespread use of the pesticide DDT was causing the bird's eggshells to thin -- to fatal levels.
"We went out, retrieved dead eggs and analyzed them," recalls Bradley.
Through intensive management efforts, the tundrius falcon, found most frequently around the Rankin Inlet region, was downlisted to vulnerable.
The falcons, after being trapped by researchers, still "have dangerously high levels of DDTs," warned Bradley. "DDTs are banned in Canada and the U.S. We still manufacture them and sell them to other countries (such as) South America."
"We found birds had 10 to 14 parts per million in their blood. We start noticing reproductive problems at 20 ppm," Bradley says. "It's good news they're off the endangered list, but no reason to get complacent."
The whooping crane, meanwhile, is still clinging to the edge of survival. And Wood Buffalo National Park still contains the only wild nesting ground in this part of the world.
Each year the tall and graceful birds fly to Texas, where, along the coast in the Gulf of Mexico, they winters in the Aransas Wildlife Refuge.
"This year 159 cranes left Texas, of that there are 49 nesting pairs in Wood Buffalo" said Doug Bergeson, park officer in charge of whooping crane studies. That ties the record for the most nesting pairs Wood Buffalo has ever seen.
A current study Bergeson and other scientists are conducting focuses on chick mortality and the whooping crane diet.
Scientist have been baffled by the hatchlings of the whooping crane -- two eggs hatch and only one tends to survive. And since such survival rates are unusually low, scientists want to find out why.
"This year (when the bird migrated back from Texas) there was only a two-bird gain," Bergeson says.
The hatchlings "seem to be doing better this year, its really wet," Bergeson said. "There is more food for them -- we think both are related in some why".
The whooping cranes return to the same area every year -- a sanctuary in Wood Buffalo. Cranes begin nesting in May and hatchlings are born in June. The cranes remain for the entire summer season in the NWT.
Most cranes, Bergeson says, stay together as a family. Males will mate with the same female most of their lives.
Water sources may also play a role in their past decline and possible future recovery as they are primarily aquatic animals.
We know from watching them, they tend to eat snails and things found in the water," says Bergeson. "We watch were they feed from aircraft."