The Critical Indicator: Whooping Cranes

Wood Buffalo-Aransas (natural) flock

The Endangered Species Act of 1973 protects species and also “the ecosystems upon which they depend.” As such, protecting the whooping crane is about more than just preserving an endangered species.  In Texas, the whooping crane serves as a “canary in the coal mine” for the overall health and viability of the Guadalupe River Basin and bays.

In 1941, the whooping crane population numbered only 16 birds. Since then, conservation efforts have been able to restore the world’s only naturally migrating flock to include more than 250 birds that breed in Canada and winter in the Aransas National Wildlife Refuge on the Texas Coast. While the whooping crane is a federally protected endangered species, its survival is still at risk due to habitat changes yielding the loss of its primary food source, blue crabs and wolfberries. The diminished number of blue crabs and wolfberries have been tied directly to the increase in salinity levels around the Aransas National Wildlife Refuge.

Tom Stehn of U.S. Fish and Wildlife Service transports an emaciated whooping crane to receive emergency veterinary care. The endangered bird died on its way. (December 2008). Image courtesy of USFWS

The flock had increased to a high of 270 in the spring of 2008. The 2008-2009 year was the worst in recent history for the Whooping Crane, with a death toll of 57 birds, a staggering loss of 21.4% of the flock—of which 23 deaths, or 8.5% of the flock, occurred in Texas during their winter at Aransas. This is rivaled only by the 1990–1991 winter when 11 birds out of 146 (7.5%) of the flock died.

The scientific data behind these deaths clearly shows that the reduction in freshwater inflows from the Guadalupe River Basin has directly impacted the number of blue crabs and subsequently impacted the whooping crane population. The struggle that the whooping cranes are experiencing is of great concern and unfortunately a critical indicator of what lies ahead for the bays and estuaries on the Texas Coast.

TAP’s salinity studies produced by our consulting scientists show that full use of existing water rights, coupled with proposed new water permits, diverting water from the Guadalupe will dramatically increase the salinity levels in the bays and estuaries along the Texas Coast. This impact will not only harm the whooping crane; it will also have a devastating effect on the fishing, recreational and tourism economy.

Ultimately, the argument to protect the whooping cranes is not simply a desire to save an endangered species. The cranes along the Texas Coast provide us with an early warning system of the overall health of the Guadalupe River Basin and bays. If freshwater is not flowing in sufficient amounts that means undue stress is being put on the entire water system. But we should remember that the whooping crane is the most recognizable endangered species in the world.  Mismanagement of water in the Guadalupe River Basin is destroying the winter habitat of these magnificent birds—and killing them.