Saturday, May 20, 2023

Gray-backed tern returns to Palmyra Atoll

 The Nature Conservancy has attracted gray-backed terns back to Palmyra Atoll after they were lost to the island, likely due to rat predation.

(Image: Gray-backed tern chick. Credit: The Nature Conservancy.)

Researchers used wooden decoys and recorded bird calls to try to convince the terns--and seven other seabird species--to land and to nest on Palmyra. A single gray-backed tern was raised on this island this season, the first in recent memory.

Gray-backed terns, formerly Sterna lunata and recently recategorized Onychoprion lunata, are pākalakala in Hawaiian. They are one of eight seabirds known to the part of the ocean that contains Palmyra, but which have not been found nesting there in recent years. They likely were preyed on and their breeding colonies removed by rats that came during World War II.

Rats were eradicated from the island in 2011. In 2020, The Nature Conservancy began trying to call the missing seabirds back to the island with loudspeakers playing recorded nesting calls, and with wooden bird decoys. These techniques have successfully called in birds in other projects.

Gray-backed terns are the first to respond.

These birds are speckled as chicks--as shown in the photo above--but as adults they have white bottomsides, gray backs, and a black head with a white stripe over the eye. 

Palmyra Atoll, roughly 900 miles south of Hawai'i, is jointly managed by The Nature Conservancy and the U.S. Fish and Wildlife Service. 

© Jan TenBruggencate 2023


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