By Anton Caputo – Express-News
The severe drought gripping Texas is turning a promising year for the endangered whooping crane into the second-deadliest on record.
Eighteen of the majestic birds have died in their winter home on the coast this season, likely because of food and water shortages caused by the record drought, Aransas National Wildlife Refuge Manager Dan Alonso said.
The 18 birds represent almost 7 percent of the flock’s population this season. The highest mortality rate on record was 1990 when 7.5 percent of the flock died while wintering in Texas.
The desperate situation has prompted wildlife biologists to break a “wildlife management taboo” and put out corn and water to help the birds make it through the winter.
The U.S. Fish and Wildlife Service also is making efforts to more stringently enforce its no-crabbing rules within the 115,000-acre confines of the refuge. That’s an attempt to save the dwindling population of blue crabs for the whooping cranes.
“That is what we are presently doing to help the whooping crane get back on their feet or at least keep any more from dying,” Alonso said.
The cranes will migrate within the next month on their 2,400-mile journey to their summer home in Wood Buffalo National Park in Canada.
Standing 5 feet tall, the whooping crane is one of the most iconic and endangered birds in the world.
Habitat loss and hunting nearly wiped out the species in the past century. The number of cranes dipped to as low as 15 in 1945and the crane was declared endangered in 1970.
But a concerted effort to bring back the birds has been successful. Last year, there were 500 whooping cranes in North America for the first time in a century. And the Texas flock, which is the last wild migratory flock in the world, hit a record 270 this season before the die-off.
Most agree that the record-setting drought afflicting Texas is behind this year’s high mortality. But one dead bird also tested positive for a virus that has been detected in a captive whooping crane flock in Florida. It’s the first time the virus has appeared in the wild Texas flock.
“They are running a number of tests to determine what else might be present,” Alonso said. “There could be other issues out there that we are not aware of.”
Many have pointed directly to the drought’s impact on the state’s blue crab population as a likely cause of the strain on the whooping crane flock. Alonso said many of the areas surveyed in the refuge that typically contain blue crab were devoid of the critters this year. Blue crabs, which can make up as much as 85 percent of the bird’s diet, require a freshwater inflow in the coastal estuaries for a healthy habitat.
Norman Boyd of the Texas Parks and Wildlife Department said blue crab numbers have been running low in the Guadalupe estuary since the mid 1990s, and he cautioned against blaming the current lack of fresh water solely on the downfall of the whooping crane’s favorite food. The state is investigating a number of possible causes, he said, and over-fishing may be one of them.
“Make no mistake, freshwater inflows are very important to crabs, but it’s hard to pin down a one-to-one relationship in our crab catch rate and freshwater inflows,” Boyd said. “Our catch rate has dropped off during the past decade and we’ve had wet years since then and we don’t see the crab population spiking during those wet years.”
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