A Project Tracks Oystercatchers to Save Them
Wildlife biologists are on the trail of a much-beloved beach bird, trying to get a fix on where it spends the off-season.
None of the chicks survived. The runt died early on, a common casualty among nestlings. The second chick disappeared overnight--probably killed by a predator. The third succumbed to a broken wing shortly after it fledged. "Oreo and his mate did everything right; they were good parents," Addison said. "It just takes one piece of bad luck to lose a chick. So the precariousness of their success is the takeaway. They have a hard enough time with all of the threats they face--tides, random bad luck like a broken wing, temperature stress, predators--and we add human disturbance."
At the end of summer, the number of birds carrying transmitters was half of what the researchers had aimed for. "We've got fewer birds," Addison said, "and we hope not to lose any more. But this is fieldwork; you're dealing with the elements, all of these things are out of our control. You do as much as you can, hope for the best, and see what happens. We're also learning how to do this better."
The project's online map of the oystercatchers' locations shows that some of the birds are moving. Mind you, oystercatchers are not marathon migrants like red knots, peregrine falcons, Swainson's hawks, or hummingbirds that can cover thousands of miles on a one-way trip. Oystercatchers banded in Massachusetts are sometimes sighted in southern Florida, more than 1,000 miles away. But some birds don't migrate at all. Others hopscotch along the coast. Still, the information that can be gathered by tracking them is as important as ever.
"In North Carolina oystercatchers are a species of special concern," Addison explained. "From Texas to Maine there are about 11,000." In recent years population numbers have begun to increase slowly but steadily, indicating that species protection and habitat management on the birds' breeding and wintering grounds have helped the population stabilize. The new tracking data will further pinpoint some of the places between the breeding and wintering grounds that are key to the oystercatcher's long-term survival. "What are the places that birds need to make a successful trip--whether it's a 200-mile journey, a 300-mile journey or a 3,000-mile journey? Knowing which areas they use as stopover sites tells you about their needs, and having that info is helpful to their conservation."
This week the birds still wearing tracking devices have been seen frequently roosting with other oystercatchers, something they didn't do in the territorial summer breeding season. One of them recently flew as far as South Carolina's central coast, and it seems to be hanging out there--at least for now--foraging in the mudflats with the other red-billed birds. During the next few months some roosts may grow to number in the hundreds, or more in some popular wintering sites. "We can have seen roosts of a couple thousand birds in Florida," Simons said. "When you're thinking about the entire population being 11,000 oystercatchers, that's significant. You may have 20 percent of the population in one spot."
In February, many of those birds should start heading back to their summer beaches and preparing to breed. With any luck, when they arrive in early March, the remaining three will still be wearing their designer backpacks.
Addison and Simons will be waiting, hoping to find them once again shucking oysters at the local raw bar.