Texas drought threatens whooping cranes as food dwindles

The devastating drought in Texas is raising worries that the parched conditions could harm the only self-sustaining flock of whooping cranes left in the wild.

The lack of rain has made estuaries and marshlands too salty for blue crabs to thrive and destroyed a usually plentiful supply of wolfberries, two foods that the cranes usually devour during their annual migration to the Texas Gulf Coast. The high-protein diet is supposed to sustain North America's tallest bird through the winter and prepare it for the nesting season in Canada.

In addition to the loss of blue crabs and wolfberries, a long-lasting "red tide" — a toxic algae that blooms in salty water — has made it dangerous for the birds to eat clams, which retain the algae's toxin and can pass it along the food chain.

"We're very apprehensive, very concerned, monitoring the population very closely to see what it is the reaction might be," said Dan Alonso, manager of the Aransas National Wildlife Refuge in Texas, the winter home of about half of the 300 cranes in the flock.

In 2009, when Texas last suffered a severe drought, an estimated 23 whooping cranes died between November and March, when they head north to nest in Canada's Wood Buffalo National Park. Tests indicated some had contracted rare diseases and were undernourished. Scientists believe some died of starvation.

This year, at least one crane has already died, Alonso said.

Scientists are alarmed because they don't normally see dead birds so early in the season. Usually, only 1 percent — or about three birds — die over the winter.

A century ago, the whooping cranes' majestic 5-foot frame and mournful call were common across the Texas shoreline and as far away as the East and West coasts. By the 1940s, the pesticide DDT and disappearing habitat had decimated the population, leaving only 14 birds in the country. The ban of DDT and efforts by scientists and Gulf Coast residents who view the cranes as a part of the tranquil landscape helped rebuild a small population.

In addition to the Texas flock, a smaller group cared for by conservationists migrates between Wisconsin and Florida by following an ultralight aircraft. The birds are trained to think of the aircraft as their mother.