by John Tedesco
EXPRESS-NEWS COASTAL BEND BUREAU
Metro / South Texas
All content (c) San Antonio Express-News
ARANSAS NATIONAL WILDLIFE REFUGE — In an annual migration that spans 2,500 miles, the last truly wild flock of endangered whooping cranes is beginning to arrive in South Texas.
Standing 5 feet tall, with black wing tips and a crimson crown of feathers, North America’s tallest bird is staking out territory along stretches of marshland northeast of Rockport, where the flock will remain until April.
“They’re very impressive and majestic,” said Tom Stehn, whooping crane coordinator for the U.S. Fish and Wildlife Service. The cranes, which were named for their bugle-like call, have a 7-foot wingspan.
While “whoopers” probably never existed in large numbers through the 1800s, they flocked to sites across the country. Each location became ingrained in generations of cranes that mate for life and follow the same migratory routes, year after year.
But the rare birds came close to extinction after hunting and human development took their toll. By 1941, their numbers had dwindled to 15 birds.
Today, after a decades-long international effort to protect the endangered species, about 400 whooping cranes live in the wild and in captivity. The only flock that exists without the help of people flies every year to Texas from Wood Buffalo National Park in Canada, where they nest in the summer.
Along a stretch of marsh grass and brackish water called Sundown Bay, which is part of the Aransas National Wildlife Refuge, dozens of cranes were visible last week, each one treading patiently through the muck and weeds as their heads drooped low to feed.
The cranes were hungry after their trek. Roughly half of the 174 birds from Canada have arrived in the Coastal Bend so far. Rather than flying in a large armada, whooping cranes travel in pairs or small groups, heading to the refuge and nearby Matagorda Island.
Each pair stakes out up to 1,000 acres of territory that it guards from other whooping cranes to protect their food supply.
“You’ll see them patrolling their boundaries,” said Craig Clark, one of several nature guides in Rockport who take tourists bird watching.
Clark’s boat, the Jack Flash, chugged slowly toward scattered whooping cranes, their white feathers standing out in the grass.
A few birds, juveniles, had pale brown feathers. “They’re awfully big birds,” Clark said. “I mean, they stand five feet tall. When they’re flying it’s like a big hang glider.”
The number of birds expected this year is down somewhat from the previous two years.
But while Stehn said the decline is disappointing, he didn’t see any reason to be alarmed.
“It’s kind of disappointing. We like to anticipate a small increase,” said Stehn, who said the crane population tends to fluctuate from year to year.
Wildlife workers in Canada last summer reported finding 52 nests — a record number — and 44 chicks hatched.
But by August, only 14 of the young birds survived.
The reason for the death toll is something of a puzzle.
The flock is vulnerable to electric power lines, hurricanes, red tides and pollution spills.
Th e Gulf Intracoastal Waterway, a man-made channel that handles barge traffic along the Texas coast, runs through the middle of the whooping cranes’ habitat and poses the main threat to the birds, according to a June report by the Fish and Wildlife Service.
Nearly 23 million tons of petroleum and chemical products were transported by barge in 1999 between Galveston and Corpus Christi, which includes the area near the refuge, according to the U.S. Army Corps of Engineers.
“Barges go through there all the time,” said Bill Wilson, a nature guide who pilots the Jack Flash tour boat. “A spill would be a disaster.”
Texas’ water woes could also have an impact on the whooping cranes.
As growing communities guzzle more water, rivers that flow into coastal bays will nourish fewer blue crabs, the whooping cranes’ principle food source, according to the Fish and Wildlife Service.
One plan to boost San Antonio’s water supply targets the Guadalupe River, which rejuvenates the crane’s habitat.
Susan Butler, resource manager for the San Antonio Water System, said a proposal to pump the water to San Antonio wouldn’t stifle the river’s flow. But the plan has Stehn and others worried.
“The scary thing is, if San Antonio doubles in size as projected, where’s the water going to come from?” Stehn said.
jtedesco @ express-news.net