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Dwindling oyster catchers puzzle reseachers
Researchers on St. Catherines Island are trying to figure out why the population of the oyster catcher is dwindling. - photo by Photo provided.
The local oyster catcher population is dwindling and researchers on St. Catherines Island say they’re not sure why.
“It’s a bird. I don’t know if you have seen them along the coast. It has an orange bill, it’s black and white and it’s fairly recognizable,” said Susan Inman, a wildlife manager currently working on the island. She keeps a color photo of the bird on her office wall. “Basically, the population is declining and we don’t know why.”
The South Dakota native-turned Midway resident said the bird is one of the coastal island’s prominent species and she’s happy the St. Catherines Island Foundation recognizes the importance of restoring the oyster catcher population.
“It’s a project the island has taken on,” Inman said. “They fund it for us. They give us vehicles and the support because they understand it’s a keystone species and they understand the importance of it. It’s all about dealing with populations and how to expand the populations successfully and carefully.”
A keystone species is a species that plays a critical role in maintaining the structure of an ecosystem and whose impact is greater than might be expected based on its biomass. Such species affect many other organisms in an ecosystem and help determine the types and numbers of other species in a community, according to marine biologist R.T. Paine’s book “A Conversation on Refining the Concept of Keystone Species.”
Inman said the St. Catherines study started three years ago and will provide data for future comparisons by island researchers and other entities such as the Georgia Department of Natural Resources.
She said researchers still are trying to determine whether over development, predators or other environmental issues caused the oyster catchers population to decline.
Inman said they don’t think food is a factor. The coastal waters they feed in are clean and provide an ample supply for the birds. Predators could be a factor but Inman said, “Typically, the areas that they are located don’t have that many predators out there. We do have the pigs and the raccoons but they prey more on the sea turtles and other species.”
The wildlife manager said oyster catchers lure away potential predators from their nests to protect their eggs.
Solving the population decline mystery is just one aspect of the St. Catherines group’s research. Inman said they’re also working on ways to increase the population.
“Right now, we are taking the full clutch, which is all the eggs in one nest, and giving them the dummies,” she said, displaying a cluster of decoy eggs. “We take half the nests and incubate them artificially.”
She said the birds don’t realize they are sitting on decoys.
“The bird really doesn’t know the difference,” she said. “If they have two eggs, we give them two eggs. If we just went out and pulled all the eggs they would think their eggs were gone and they would go out and build another nest and lay more eggs. So we give them something to sit on.”
Inman said the eggs are incubated and chicks are returned to the parents immediately after or just before they hatch.
“We are going to see if we can increase the population by doing this,” she said.
Inman said a female oyster catcher can lay three to four eggs per clutch and multiple clutches per year. The birds tend to nest near water.
“So they can see what’s coming,” she said. “They grow up pretty quick and they will be almost full grown in about three weeks. The difference will be that an adult has a complete orange bill and the developing chick’s bill will be half orange and half gray. They will be able to eat. These guys will come down to the water with their parents and watch what they are doing and then they’ll try it. The parents will feed them a little bit but it’s mostly the small chicks will come up to them. They are real good parents.”
The wildlife manager said they are able to keep tabs on the birds.
“We know which birds are which because we do band them,” she said.
There still is plenty of research to be done, Inman said, but she’s excited about the options for helping to restore the species.
“We are coming down from the season right now and we haven’t crunched the numbers or data yet,” she said. “But we definitely have a lot of chicks out there that we have banded and have actually gone to flight.”

Editor’s note: This story is part two of a series on the animals on St. Catherines Island and the researchers and
specialists who care for them.
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