The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Thursday, November 05, 2009

Welcome Whoopers Back
by Ro Wauer

Yes, it is again the time of year that those very special winter Texans – whooping cranes - are returning to Aransas National Wildlife Refuge and environs. A recent article in the Audubon Outdoor Club Newsletter (Kathy Griffith, editor) of Corpus Christi reminded me of this marvelous event. Kathy’s article also provided good up-to-date information on the bird’s status. Much of the material below is taken from her “Whooping Crane Report.”

Last winter has hard on our whoopers! Drought, decreased inflows into the Gulf from the Guadalupe River, and withdrawals of water for human uses reduced bay productivity that negatively impacted blue crabs, the whooper’s principal food supply. Those impacts, along with housing developments next to marshes, whooper’s foraging sites, add to the local impacts. And “in the migration corridor, the cranes are facing a proliferation of wind farms and associated power lines. Collisions with power lines is the number one cause of mortality for fledged whooping cranes, and the miles of lines continue to grow substantially.” There is good reason why whoopers are endangered.

Only 247 of our South Texas whoopers made it through the 2008-2009 winter to migrate northward to their breeding grounds in Wood Buffalo National Park in Canada’s Northwest Territories. Those birds found adequate nesting conditions, but only 22 chicks fledged from 62 nests, below the average production rate. “Perhaps the weakened condition of the birds from the previous winter had taken its toll. With the drought continuing in south Texas into the fall of 2009, wildlife officials are leery of what conditions for the flock will be like at Aransas in the 2009-2010 winter. Water holes were re-conditioned on the Aransas National Wildlife Refuge to ensure the cranes will have fresh water to drink if the marshes remain above the threshold salinity of 23 parts per thousands when whooping cranes must find fresh water to drink.”

At the present time there are a total number of 536 known whooping cranes, 384 in the wild and 152 in captivity. “Young whooping cranes bred in captivity are being reintroduced in the wild in two flocks in the eastern U.S.” In the fall of 2001, eight whoopers were flown behind an ultralight aircraft between Wisconsin and Florida; “five of those survived the winter and started the migration back north on their own in April 2002. Additional birds were reintroduced in the next eight years, with 108 whooping cranes now migrating in the eastern U.S. However, the birds are struggling to hatch young with the adults abandoning their nests just prior to hatching the eggs due to swarms of black flies bothering the adults.” A second wild flock consists of 29 remaining non-migratory whoopers in central Florida. “That reintroduction effort has been abandoned as the cranes struggled with poor rates of reproduction and low survival mostly tied to re-occurring drought.”

The South Texas winter flock of whooping cranes is very special! Too often they are ignored and considered unimportant. But they are more than an ideal curiosity. They are a national treasure that we must appreciate and maintain. As Kathy wrote: “It will take increasing vigilance by man if this species is to survive and provide a thrill for your great-great-grand children to see, just as they provide enjoyment for Texans and thousands of visitors from around the world annually that visit Aransas NWR to see this magnificent species.”