Audubon North Carolina has 10 amazing chapters across the state and each month we focus on one chapter's contributions to bird preservation and conservation.This month, we get to know Cape Fear Audubon – www.capefearaudubon.org. This post, written by one of our biologists in the field, focuses on the important research being conducted in the region.
Audubon North Carolina's coastal program has participated in or assisted many students' research projects over the years. This year, two graduate students from UNC-Wilmington carried out master's research projects focusing on contaminants in Royal Terns, Sandwich Terns, and Brown Pelicans. Their work included Audubon's islands on the Cape Fear River and at Ocracoke Inlet. One of the students, Kiersten Newtoff, agreed to write about her work for our blog.
Hello! My name is Kiersten Newtoff, and I am a graduate student at UNCW. I am working with Dr. Steve Emslie on my Master’s in marine biology. My thesis research focuses on Brown Pelicans, and how their diet and mercury exposure varies along the North Carolina coastline in their breeding colonies.
Mercury is a toxic pollutant that is particularly harmful to children as they develop during the mother’s pregnancy. Mothers exposed to mercury pass it on to their children who, when exposed to high concentrations, will develop neurological birth defects. Birds are also prone to the harmful effects of mercury, exhibiting neurological problems and reduced reproductive success.With such negative health effects, studying the distribution and the factors influencing mercury concentration are important to protect healthy wild bird populations, as well as understanding the impact on human populations.
Studying mercury directly through water samples is feasible, but it doesn’t reflect how mercury accumulates in the food chain—and how it impacts wildlife. Brown Pelicans, the focus of my research, are the top predator in the marine food web, and can provide valuable information on mercury concentrations.
This summer, I have been privileged to work with Lindsay Addison and Maria Logan of Audubon North Carolina, Sara Schweitzer of the NC Wildlife Resource Commission, and longtime banders John Weske and Micou Browne who band Brown Pelicans and other shorebirds along the east coast from North Carolina to Maryland. I visited each of the seven pelican breeding colonies in North Carolina to collect eggshells and feathers from the chicks. This work took me from Oregon Inlet to the Lower Cape Fear River– nearly the entire length of the North Carolina coastline.
By analyzing the mercury in these tissues, I can get an idea of what areas may be exposed to more mercury, which could potentially lead to environmental health problems in the future. For the birds, mercury levels in eggshells reflect the females' mercury levels, while feathers from chicks reflect levels in the fish the chicks are eating.
Fortunately, my analyses so far have not shown high levels of mercury that could cause problems. However, I have found that of the islands, the only significant difference in mercury levels was between a few islands in the Cape Fear River, South Pelican Island and Ferry Slip Island. I’m still investigating the reasons behind this difference, but it’s possible that one of the colonies is feeding in or near the salt marsh. Salt marshes are known for having more mercury because of bacteria found in the marsh convert mercury into a form more readily incorporated into living organisms' bodies.