On their wintering grounds along the Gulf Coast of Texas, Whooping Cranes feed almost exclusively on blue crabs. The coastal marshes provide excellent habitat for the crabs if salinity levels remain moderate, which is determined primarily by the amount of freshwater flowing into the coastal waters from the Guadalupe River basin.
When freshwater is reduced, due to drought or use of the river’s water upstream, fewer crabs are available for Whooping Cranes. In such cases, the cranes weaken, resulting in higher mortality on their wintering grounds and fewer chicks on their breeding grounds in Canada the following spring. How will this affect the future of this endangered species?
During the winter of 2008-09, a prolonged drought coupled with upstream water use resulted in insufficient freshwater inflows to the coastal marshes of southeast Texas. Continued upstream use of water resulted in a longer period of very high salinity levels along the coast than would have been the case under natural conditions. When the cranes arrived from their long migration, many former feeding areas were either dry or had few crabs. Some cranes were forced to move to other wetlands in search of food and drinking water, and others died on their territories. That winter, from a population of 273 cranes, 23 perished, or 8.5% of the population.
Droughts are natural in the southwest, and the Whooping Crane population can recover from such setbacks when they occur infrequently. However, the State of Texas is granting permits for upstream water withdrawal from the Guadalupe basin to such an extent that freshwater inflows to the coast are expected to be significantly reduced or even eliminated on a much more frequent basis. At the same time, the continued loss and degradation of key wetland sites further limits the potential for the Whooping Crane population to find suitable habitats along the coast. We expect increasing mortality of cranes in the coming years, and possible extinction of the flock, unless a more sustainable approach to water and wetland management is undertaken.
To address these critical issues, the International Crane Foundation and our partners in Texas are undertaking new research and outreach activities aimed at securing the long-term survival of Whooping Cranes on their wintering grounds, and – by extension – the coastal economy of southeastern Texas. This work includes research on the effects of sea level rise on Whooping Crane habitat in coastal Texas, which is helping us identify future areas for protection as sea level and suitable coastal habitats change (learn more about this research). To learn more about our conservation goals in coastal Texas, click here.