Rats! Streaked Shearwaters on Sasu Island, Korea suffer predation during hatching

Ki-Baek Nam (Korea Institute of Ornithology, Kyung Hee University, Seoul, Korea) and colleagues write in Korean in the journal Ocean and Polar Research on the effects of predation by Norway Rats Rattus norvegicus on Streaked Shearwaters Calonectris leucomelas when breeding.


The paper’s English abstract follows:

“The seabird plays an important role as one of the indicator species for the status of and changes within marine ecosystems.  Therefore, the conservation of seabirds and their habitats is important for maintaining the structure and function of marine ecosystems.  Biological invasions affect most ecosystems on oceanic islands.  In particular, Rattus spp. is the invasive species with the greatest impact on the seabird population.  Introduced predators, like rats, severely affect seabirds and endanger them worldwide.  The breeding population of Streaked Shearwaters Calonectris leucomelas in Sasu Island is one of biggest seabird colonies in Korea, and the Norway Rat Rattus norvegicus is known as an alien predator in this island.  In this study we investigated rates of burrow occupancy and breeding success of Streaked Shearwaters for 7 years, and the impact of Norway Rats on the breeding success of Streaked Shearwaters breeding in Sasu Island for 4 years.  Our results show that the percentage of breeding burrows decreased according to breeding stage during several years in the monitoring period, and that predation by the Norway Rat was the main cause in hatching failures.  Consequently, although our results indicate that their breeding population is not likely to decline, Norway Rats have been affecting the breeding status of Streaked Shearwaters on Sasu Island during the last decade.”


Nam, K.-B., Lee, K.-G., Hwang, J.-W. & Yoo, J.-C.  2014.  Variation in breeding burrows of Streaked Shearwaters breeding in Sasu Island, and predation rates by Norway Rats.  Ocean and Polar Research 36: 49-57.

John Cooper, ACAP Information Officer, 10 May 2014

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