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Drought Threatens Whooping Cranes


The drought that has plagued the Southwest for the past several years is taking a toll on the world's last wild flock of endangered whooping cranes, say staff at Aransas National Wildlife Refuge, where the birds winter along the Texas Gulf Coast. Flock numbers are down almost 7 percent from last year's record of 270 birds. Fifteen cranes never arrived at Aransas Refuge and are presumed dead.

Eighteen others have died, apparently due to shortages of food and water. Now, disease may also be thinning the territorial flock of five-feet-tall birds.

Declared an endangered species in 1971, the whooping crane has made a comeback from a low of 15 birds in 1941.

Although refuges seldom feed wildlife, Aransas Refuge staff is supplementing the birds' diet with aflatoxin-free corn at feed stations after noting a sharp drop in the birds' usual diet source – blue crabs. "Crabs need fresh water to reproduce," said 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."

U.S. Geological Survey researchers recently confirmed the presence of a wasting virus called infectious bursal disease. Strains of the virus have previously been found in captive cranes but not wild ones.

Aransas Refuge staff is also enforcing a longstanding regulation prohibiting commercial crabbing in marshes of the 115,000-acre refuge. "We mobilized to collect every trap," said Alonzo. "We picked up 411 traps."

The flock is due to fly north on its 2,400-mile annual journey to Canada by mid-April. Refuge staff hopes the birds are strong enough for the journey.

Is there anything the public can do to help? Alonzo suggests that people keep some distance when viewing the birds. "You can get a decent picture while minimizing the harassment of the birds."

Contact: Dan Alonzo, Aransas/Matagorda island National Wildlife Refuge Complex, 361-286-3559 or dan_alonzo@fws.gov.






Last Update: November 23, 2009
 

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