Confirmation of Breeding by Japanese Murrelets Synthliboramphus wumizusume at Kobiro Islet, Miyazaki, Japan

We conducted nest surveys of the Japanese Murrelet Synthliboramphus wumizusume at three islets (Kobiro, Nakabae, and Setsuribae) near the largest breeding colony of this species at Birojima, Miyazaki, Japan, on 5 April 2019. The species had been known to breed at Kobiro Islet in the early 1960's but no surveys have been conducted there since 1994. We found five nests with incubating adults, and two nests with eggs only, at this islet. We found no evidence of murrelet breeding at Setsuribae Islet, where potential nesting habitat was available but frequent visits by terrestrial mammals from mainland Kyushu probably prevent murrelet breeding. We found no suitable breeding habitat for murrelets on Nakabae Islet.