• Korean Journal of Veterinary Research
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• v.35 no.3
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• pp.505-513
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• 1995

Seventy wild rats were caught from Seoul city, Kyonggi, Kangwon, Honam, and yongnam provinces. All of them were in same species, Rattus norvegicus, except two R rattus from Kyonggi province. Seventy sera from wild rats were studied by immunofluorescent antibody assay for evidence of infection by spotted fever group rickettsia. The antidody prevalance was 37.14%(26/70) for spotted fever group rickettsia. The sero-prevalence rates for spotted fever group rickettsia antibody was the hightest in Kyonggi province with 55.56%(10/18), yongnam province with 50.00%(10/20), Kangwon province with 25.00%(2/8), Seoul city with 18.75%(3/16), and Honam province with 12.50%(1/8). The sero-positive rates difference between sexes were higher in female with 46.15%(12/26) than in male with 31.81%(14/44) for spotted fever group rickettsia. Twenty six of 68 Rattus norvegicus with antibody for spotted fever group rickettsia were in subadult with 50.00%(6/12), young adult with 38.89%(7/18), middle-aged adult with 35.29%(6/17), and old adult with 33.33%(7/21). No antibody was detected from R rattus.

• Ocean and Polar Research
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• v.36 no.1
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• pp.49-57
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• 2014

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.

• Korean Journal of Environment and Ecology
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• v.21 no.1
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• pp.30-37
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• 2007

Pellets and prey remains were analyzed to compare diets and foraging tactics of Eurasian eagle owls (Bubo bubo) in two different habitat types: forested areas and open fields. Overall 150 prey items of three taxa were identified from 66 pellets and 82 prey remains, and the birds were the most important prey in biomass (78.04%) and in frequency (56.67%). Eurasian eagle owls frequently used rats (Rattus spp.), ring-necked pheasants (Phasianus colchicus), and stripped field mice (Apodemus agrarius), but the ring-necked pheasant was most important in biomass in both habitat types. The owls generally foraged various prey in biomass but the mean mass of vertebrate prey used by the Eurasian eagle owls was 503.3g in central Korea. According to the comparison of diets in the two different habitat types, the owls used bigger and more diverse prey in forested areas than in open fields. In forested areas, the Eurasian eagle owls frequently foraged the pheasants and Mandarin ducks (Aix galericulata), but they preferred prey of particular sizes to prey of particular taxa. In open fields, however, the owls showed opportunistic foraging tactics by selecting many small mammals such as rodents or a few large birds.