Whoopers work to survive
by Ray Kirkwood, - Certified Texas Master Naturalist, whooping crane specialist
March 16, 2010 at midnight
Updated March 15, 2010 at 10:16 p.m.
One of the icons of Texas is in trouble. The whooping crane has been a symbol of Texans' love of the wild for many years.
This magnificent bird nearly vanished from the earth during the 1930's and 40's.
But due to good fortune and much hard work by Texans and Canadians, the whooping crane recovered to a record 270 birds in the fall of 2008.
However, during the winter of 2008 and 2009, things went very wrong here in South Texas, and it hasn't been much better this winter.
To understand what went awry, you need to know what the whooper needs to survive our winters.
The whooping crane is an omnivore - he can and will eat nearly anything. But in order to thrive, he needs an abundance of blue crabs in the waters along the coast during the winter.
And not just any blue crab; one that is at least an inch across the shell but not so big that it is too hard for the crane to dispatch. Silver-dollar size is about right.
Now, at that stage of the blue crab's life, it needs water that has some salt in it, but is not nearly as salty as the waters of the Gulf of Mexico. When the water is roughly half as salty as Gulf waters, it is ideal for blue crabs.
Also, when the water is only that salty, the whooping crane can drink it. What happens when the water gets too salty?
The crabs disappear, and the cranes must fly inland to find a fresh water pond to drink from.
The whooping crane is deprived of his staple diet (the blue crab) and must expend extra energy just to get a drink of water. And, of course, it is around these fresh-water ponds that the bobcats and alligators hang out.
If you were here in South Texas last winter, you know that we were in one of the worst droughts in history. We had not had any significant rainfall in nearly two years.
This fact alone would have made the waters of the whooping cranes' habitat saltier. But this situation has happened before, and the cranes survived the dry spell.
The drought was not the major reason for the whoopers' problems. The coup de grace for the cranes last winter was the fact that the Guadalupe River nearly went dry. Never before has this spring-fed river been so low, and it is the flow from this river that keeps the water of the whooping crane habitat within the salt tolerance of the crabs and cranes.
Even in a normal year, we don't get enough rainfall here to offset the water evaporated by the sun.
Even in a normal year, we need the waters of the Guadalupe River to flow to keep our coastal waters healthy.
Last winter, coastal waters got much saltier than the Gulf of Mexico from a combination of the drought and low water flow from the Guadalupe.
The blue crabs disappeared; the whooping cranes got hungry and thirsty; 23 whooping cranes died.
The migration brought 270 whooping cranes here in the fall of 2008. Only 247 left here in the spring of 2009.
This winter the rains came, but they came too late. The blue crabs have not had time to reproduce. The whooping cranes are wandering around outside their normal habitat looking for something to eat.
The one good thing is that with our current abundance of rain, the cranes have been able to drink the water. None have starved so far, although one baby has died.
Still, as these most famous of winter Texans get ready to make their long trip back to their summer home in Canada, they are not as strong and healthy as they should be.
Ray Kirkwood, is a colleague of Master Naturalists Paul and Mary Meredith. Contact them at firstname.lastname@example.org.