Protecting Maine’s Coastal Treasures: Vital Conservation Efforts for Common Eiders

Newswise — Spending a sunny day on a boat in Casco Bay isn’t a bad summer job, at least not for BRI biologists Helen Yurek and Logan Route. On a Thursday morning, we loaded up into a boat to set off in search of Common Eiders, sea ducks that spend most of their time along rocky seacoasts.

Our first stop is Jenny Island, which is where we see our first eider broods. These broods consist of mother hens and their offspring. The boat slows, and Helen and Logan look through their binoculars to get an accurate count of how many birds there are, and their ages. The eiders are identified based on their visual characteristics, such as the number of feathers they have, and how big they are compared to some of the adult eider hens.

BRI started a pilot project in 2016 to document eider survival in Casco Bay, and the project has continued ever since. During the eider brooding and nesting season, which occurs in May through July in Maine, BRI conducts weekly surveys to ascertain the location of the broods and record their age and survival.

Helen and Logan survey the eiders using binoculars as well as through radio telemetry. The eiders are tagged with nasal discs, two different ones with a single tag on each nostril, such as a pink triangle on the left and a blue circle on the right. These nasal discs are helpful throughout the survey season in re-identifying eider hens They also use radio telemetry to track specific eider hens that researchers have banded in previous years, to see where they have moved to.

We soon cruise up to Flag Island, which is one of the largest eider nesting sites in Maine. Once a privately owned island, the land now belongs to the state, and is managed by the Maine Department of Inland Fish & Wildlife for habitat protection. With all the development happening in Maine, it’s important to protect these natural areas, which are home to many important wildlife species. Flag Island is a particularly critical habitat for eiders but also for other seabirds such as terns and gulls. The island’s protected status helps ensure that these species have a safe place to breed and raise their young away from the disturbances of human activity and development.

After scoping out the islands along the coast, the boat picks up speed and moves toward more open waters. Helen and Logan keep their eyes peeled for eider broods. They call out the number of birds they see, and their respective ages. The broods range in size, some only 4 or 5 birds total, others may be as large as 20 or more birds.

The annual surveys show that the eiders do not stay in one place. BRI’s work has led to collaborations between U.S. and Canadian agencies to understand their distribution and migration patterns. Changing environmental factors, such as a warming Gulf of Maine, are threats to the eider population in Casco Bay.

Humans tend to have a vested interest in the conservation of ducks and seabirds that they find out on the water. When these bird populations get threatened, whether it be from human or natural causes, it impacts the entire ecosystem. By understanding the challenges that these birds face, we can develop strategies to mitigate those threats and ensure the survival of eiders for generations to come.

Throughout our time on the water, Helen and Logan point out certain birds, such as cormorants and herons. Common Eiders, and seabirds in general, are part of the natural beauty of Casco Bay. The Common Eider work that BRI is doing is one of many initiatives that will help to monitor the species’ health and distribution, and is also indicative of the health of marine and coastal environments.

For more information and updates to the project, click here.