Orange-crowned Warblers in Louisiana

Posted by Scott Sillett on December 1, 2007

Scott Sillett and Brent Horton conducted a week of scouting in southwestern Louisiana, where they looked for wintering orange-crowned warblers. They were guided by Robert Dobbs, a local bird expert. Although about a dozen warblers were seen, none were captured because the bulk of the wintering population had not yet arrived.

At a later date, they will attempt to capture the warblers in order to determine where this migratory species breeds by analyzing stable isotopes in their feathers. They also want to collect blood samples to analyze levels of corticosterone, an avian energy-regulating steroid that promotes behavioral and physiological adjustments for coping with energetic challenges and environmental stressors. In addition, they hope to individually mark birds so that their survival might be monitored.

The scientists found several promising field sites in the coastal woodlands, or cheniers, of Cameron Parish. The chenier woods are recovering after being heavily damaged by Hurricane Rita in September 2005. The outlook for orange-crowned warblers is uncertain there, but it is possible that the dense regenerating vegetation is to their liking.

View Larger Map

In the interactive map above, you can see a band of darker-colored vegetation in the center. These are hackberry trees and live oaks growing on the remains of old sand dunes. This habitat is very important for migratory birds as it is the last stop before migrating over the open expanse of the Gulf of Mexico. It is also ideal wintering habitat for orange-crowned warblers.

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