Another entry in Abby’s Birdbrained Summer. Abby, the summer communication intern for the Coast Office of Audubon North Carolina, is visiting sites with Audubon’s field staff and our community of volunteers. After she goes into the field, she’ll post blogs detailing her experiences.
I recently visited natural islands in the Cape Fear River with Lindsay, Audubon North Carolina's coastal biologist. As the boat landed on Shellbed Island, Lindsay pointed out the lighthouses on both Bald Head and Oak Island, and the buildings of Southport in the distance. Shellbed Island was distinctly different from the dredge islands we had visited; it was an enormous marshy expanse, as opposed to a small, predominantly sandy area.
All of the American Oystercatcher nests I had previously seen were laid in indentations in the sand, but the pairs on Shellbed Island built their nests on enormous shell rakes. The shell rakes looked like a long dune of bleached bones, but were composed mainly of oyster and other bivalve shells. It seemed appropriate that oystercatchers nest in the remains of their preferred meal, and reminded me of the Native American doctrine to use all parts of an animal so nothing is wasted.
Alternately, the oystercatchers’ predators were wasteful, so Lindsay was able to identify the culprits. Judging by the rodent-sized holes in leftover eggshells Lindsay found, many of the eggs on Shellbed Island were eaten by rats that live in the marsh. The other threat left no evidence: overwash at high tide.
“This pair needs to go to grief counseling,” Lindsay said of two oystercatchers sitting listlessly on the beach. They recently lost their third nest, and Lindsay projected that they were done breeding for the year.
Another pair has their nest under surveillance by a bucket camera from N.C. State University. If their nest fails, there will be photographic evidence of the perpetrator.
After Shellbed Island, Lindsay swung the boat around Battery Island. The trees looked like they were covered in snow, but the snow was actually thousands of White Ibises. There have been as many as 15,000 pairs of nesting ibis on the island during breeding season, making Battery Island one of the most significant areas in North America for White Ibises. We watched the birds rise from their nests on Battery Island and fly across the water to Southport. It was a stunning sight.
In addition to the ibis, the island is home to Tricolored Herons, Little Blue Herons, American Oystercatchers, and both Great and Snowy Egrets. We did not land on the island because a disturbance could make the chicks hop out of their tree nests, leaving them on the ground, unlikely to be fed by their parents.
The last island we visited was North Pelican Island. North Pelican Island was actually formed by a deposit of dredged sand in the 1920s, but never received further deposits. Therefore, the habitat is essentially similar to a natural island, as vegetation has grown up over the decades.
When we pulled up in the boat, I was excited to see trees full of egrets, which have always been my favorite birds. I love their transformation from awkwardly wading on their too-long legs to gracefully taking flight. I particularly like the Snowy Egrets because of their flamboyantly yellow feet. Lindsay invited me to accompany her for egret banding later in the season, which I will look forward to for the rest of the summer!