Sato et al.: Swinhoe’s Storm-Petrel in Japan 133

• Main Authors: Storm-petrel Oceanodroma, Breeding Of, Oceanodroma Monorhis
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2010
• Subjects: Oceanodroma leucorhoa
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.690.7013; http://marineornithology.org/PDF/38_2/38_2_133-136.pdf

Kondratyev et al. 2000). Global population estimates range from 30 000 individuals (Boersma & Groom 1993) to 100 000 pairs (Birdlife International 2009), far fewer than the closely related Leach’s Storm-Petrel Oceanodroma leucorhoa (Boersma & Groom 1993). Most reports of O. monorhis are from observations or captures of birds outside breeding areas (Bailey et al. 1968, James & Robertson 1985, Bretagnolle et al. 1991, Cubitt 1995), whereas studies of the breeding biology of this species are very limited (Won & Lee 1986, Lee & Won 1988). In addition to having a limited population, some colonies of O. monorhis are threatened by human activities and introduced predators. Although several colonies are known to be active in Japan, most contain only small numbers of individuals (Sato 1996). Yoshida (1981) noted breeding of Swinhoe’s Storm-Petrel on the Kutsujima Islands, Kyoto, Japan, but details of this colony had remained unexamined. Because the size of the Kutsujima Islands suggested the possibility of a large breeding population, we surveyed the colony and estimated the size of the breeding population. The Kutsujima Islands (35°43′N, 135°26′E) are located in the Sea