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Paving the Way for Least Tern Nesting

April 15, 2024
least tern decoys

You may see fake wooden birds along the beach on Sanibel, thanks to a nest-attraction effort underway for state-threatened least terns, a beach-nesting bird species and the smallest tern species in the world.

Volunteers teamed up with SCCF’s shorebird and Coastal Watch staff to paint and place these wooden least tern decoys in ideal nesting locations where terns would be able to safely care for their eggs and chicks.

Least terns are a social species, often spending time together during migration and during the nesting season. When decoys are deployed, the terns recognize that there are ‘birds’ settled in a suitable and safe nesting area, and they are drawn to nest in that area,” said SCCF Shorebird Technician Aaron White. “This is a method known as social attraction.”

Least terns primarily nest in large groups, known as colonies, in large, open areas of bare sandy beaches. There are many areas across Sanibel and Captiva that may appear suitable to the terns as they search for nesting grounds. Some of these spots however, can be problematic for both the nesting birds and ongoing Hurricane Ian restoration projects, i.e. the causeway islands, which the birds attempted to nest on last year.

“Our decoys are a method to help encourage these birds to nest in more ideal locations, although they ultimately decide for themselves where to nest and it is not a guaranteed solution,” White said. “Our wonderful volunteers who helped us paint and place the least tern decoys also helped us set up enclosures around them with stakes, string, and signs to prevent disturbance of the habitat.” 

Nesting as a group allows least terns to more easily communicate and detect nearby threats such as predators, White explained.

least terns
Least terns (Sternula antillarum)

“Once a threat is detected, least terns collectively start dive bombing and defecating on the threat — yes, really — to drive it away from the colony,” said SCCF Shorebird Technician Aaron White. “Threats are not limited to predators such as coyotes or crows, they may also perceive humans as threats, so be wary of incoming airstrikes if you are walking past an enclosed least tern nesting area.”


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