Researching American Oystercatchers on the Nature Coast

Pat and Doris Leary are avid birdwatchers and citizen scientists from Fernandina Beach, FL, who volunteer their time and substantial skills to survey coastal waterbirds in Northeast Florida, coastal Georgia and Florida’s Big Bend. As they have done each winter since 2006, the Learys are conducting surveys in Florida’s Big Bend this year.  Their skill at censusing wintering shorebirds—one of the most challenging groups of birds—resighting bands, and navigating  this wild coastal region places  them among Florida’s leading field experts on the habitat usage of shorebirds in North Florida.  This is the first of several blogs in which they share their experiences and sightings, as well as the challenges these increasingly imperiled birds face.

Researching American Oystercatchers on the Nature Coast

Pat and Doris Leary

Summer's end might be referenced as the season of return. Multitudes of students return to classes, families return to workaday routines and millions of migrating birds return to wintering grounds. Amongst these are American Oystercatchers which breed all along the Atlantic coast and shift south around the autumnal equinox. Not all oystercatchers migrate, but large numbers do return to wintering areas in South Carolina, Georgia and Florida. Of Florida's "snowbirds," fewer than two hundred winter on northeast Florida's oyster-rich coast. The greater majority cross the peninsula to winter from the Big Bend "Nature Coast" to the 10,000 Islands area of Southwest Florida.

Each winter, some 1,500 oystercatchers concentrate along the Gulf coast of Florida’s Dixie, Levy and Citrus counties. Since the winter of 2006, we have engaged in our own migration by periodically crossing the state from late summer to spring to survey and monitor this large winter population. On our first survey, it quickly became evident that the birds originated from states all along the Atlantic coast. This insight was made possible by the detection of uniquely color-coded and engraved bands applied to the birds' upper legs (tibia) by researchers on the birds’ breeding grounds. The color of an oystercatcher’s band is unique to the state where it was banded, and most flocks we encountered at traditional roost sites on our Nature Coast surveys contained a spectrum of color bands.

This clever marking scheme was devised by members of the American Oystercatcher Working Group, a working group composed of biologists, researchers, managers and other like-minded interests focused on the research and conservation of the species. Because American Oystercatchers are entirely coastal-dependent along the Atlantic and Gulf they are considered a "keystone species". Their status and well-being are indicators of the health and viability of all coastal ecosystems.

To learn more about the routes and timing of oystercatcher migration, researchers have marked a few birds with satellite transmitters. One of these birds satellite-tagged in North Carolina was recently tracked to Cedar Key. Other satellite-tagged birds from Massachusetts may yet arrive on the Gulf Coast. Awareness of the importance of this region to wintering shorebirds is growing, and over the last two winters, researchers from the Florida Fish and Wildlife Conservation Commission and University of Florida conducted an intensive winter study to investigate the species use and dependence on foraging habitats around Cedar Key.  Part of that project involved the on-going restoration of eroding oyster reefs in the region.

Our on-going surveys are an essential complement to this banding, satellite tagging, and habitat use research. By collecting important band resighting and winter observations we help to build on the knowledge and insight gained from prior seasons, document the continued dependence of the migrant population on the upper Gulf region, and track the movements of individual birds, some of which have returned for seven years running.  Incidental to oystercatcher studies, we also collect data on a host of other shorebirds sharing the wintering habitat of the Nature Coast region—some of the last, best remaining habitat for this declining suite of species.

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