The Madeiran Storm-petrel Oceanodroma castro is a threatened seabird breeding on the Hide-shima (39°40'N, 142°00'E), Iwate Prefecture, in northern Japan. This small island is the only known large colony in Japan for this species. In the latter half of 1980s, nesting burrows of Madeiran Storm-petrels were confirmed to have been decreasing owing to the interspecific competition for nesting burrows between larger Streaked Shearwaters Calonectris leucomeras and this smaller species. We used small wire mesh nets at the nesting ground in order to exclude larger species from Madeiran storm petrel burrows in 1990. Results suggest that nest numbers of Madeiran Petrels have been gradually increasing in the experimental area.