Discovery of a New Breeding Site for the Endangered Japanese Murrelet Synthliboramphus wumizusume in Nagasaki, Japan

We report a breeding site for the Japanese Murrelet Synthliboramphus wumizusume discovered for the first time in March 2023 on Hahakojima (Hakoshima), a small island in Nagasaki City, Nagasaki Prefecture, off Kyushu, Japan. We counted 129 Japanese Murrelets among at-sea congregations during spotlight surveys around Hahakojima. This provided strong evidence that murrelets were breeding on the island. During a brief search of Hahakojima, we discovered 18 nests in rock crevices. Seven of these nests included incubating adults and 11 nests contained unattended eggs. We also found 22 broken eggs in open areas and observed a Large-billed Crow Corvus macrorhynchos carrying a murrelet egg in its beak. Future efforts to evaluate and reduce the impacts of crow predation at this breeding site will be required. Our findings should encourage similar survey efforts at potential breeding islands throughout the murrelet’s range to better understand the status and distribution of this threatened and vulnerable species.