• Journal of Ecology and Environment
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• v.30 no.1
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• pp.9-15
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• 2007

Black-tailed gulls (Larus crassirostris) produce alarm calls apparently related to their anti-predator behaviors, but the hypothesis that the calls are actually used as functionally referential alarm signals has not yet been tested. In this study, we performed a series of experiments using visual (a stuffed goshawk: Accipiter gentilis) and acoustic (alarm calls and a control vocalization) stimuli at 15 sites in Sinjindo-ri and Dowhang-ri, Taean-gun, Chungnam province to examine anti-predator responses of the gulls to alarm calls in playback trials. We found that the gulls' visual recognition of a perched hawk model in the absence of alarm vocalizations was weak or absent because the model was noticed in only two out of 16 trials. The gulls' responses to playbacks of the alarm call only and the alarm call with a visual stimulus differed from responses to the control vocalization in latency to approach, time mobbing, and the percentage of gulls responding, while the responses to alarm call only differed from alarm call with a visual stimulus in latency to first fly, latency to call, and time mobbing. The results of this study suggest that alarm calls of black-tailed gulls are used to elicit appropriate anti-predator behaviors that are intensified when a predator is detected visually.

• Journal of Ecology and Environment
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• v.31 no.1
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• pp.69-73
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• 2008

We studied the functional roles of two types of calls, mew calls and mobbing calls, of the black-tailed gull (Larus crassirostris) by examining responses of mixed flocks of gulls to the playback calls. Playback experiments were conducted on four days between 11 May and 5 June 2007 at 16 sites in Sinjindo-ri and Dowhang-ri, Taean-gun, Chungnam province and Imjado, Sinan-gun, Jeonnam province, South Korea. We examined the anti-predator responses of the gulls to the playback trials. We found that gull flocks initially responded to mew call playbacks by mobbing in less than half of playback trials (6/14) while all trials involving playbacks of the mobbing call and control (group mobbing) call evoked mobbing. When trials in which no response was recorded were excluded, we found that the gulls' responses to mobbing and group mobbing call playbacks was more intense than their response to mew call playbacks, in that gulls mobbed longer, more gulls responded, and gulls took flight after a shorter time interval. However, the intensity of the gulls' response did not differ in mobbing call and group mobbing call playbacks. The results of this study suggest that the mixed-species flocks of gulls discriminate between the mew calls and the mobbing calls.

• Journal of Environmental Science International
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• v.27 no.12
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• pp.1279-1290
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• 2018

Sea gulls are high trophic level consumers in the coastal environment, and thus, which have been widely used to monitor contamination biomagnified through a food web. However, such monitoring studies using sea gulls have been rare in the Korean literature. The National Environmental Specimen Bank chose eggs of a black-tailed gulls (Larus crassirostris) to serve as an environmental specimen for the long-term monitoring of the coastal ecosystem affected by terrestrial pollutants. Black-tailed gull eggs were collected from Baengnyeongdo, Hongdo and Uleungdo, and their DDTs and total mercury content were determined. The highest concentration of ${\Sigma}DDTs$ was $231.6{\pm}106.1{\mu}g/kg$ wet in Baengnyeongdo, followed by $230.0{\pm}123.8{\mu}g/kg$ wet in Ulleungdo, and $117.7{\pm}18.3{\mu}g/kg$ wet in Hongdo. In addition, total mercury was detected at $414.5{\pm}97.6{\mu}g/kg$ wet in Ulleungdo, $363.9{\pm}123.6{\mu}g/kg$ wet in Hongdo, and $237.5{\pm}42.3{\mu}g/kg$ wet in Baengnyeongdo. Relatively high concentrations of the target pollutants were recorded in specimens from Ulleungdo. Additional comprehensive and prolonged studies are required to elucidate spatial and temporal patterns of contamination in black-tailed gull eggs with regard to monitoring contaminant trends in eggs and prey.

• Korean Journal of Ornithology
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• v.25 no.2
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• pp.106-111
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• 2018

The Black-tailed gull (Larus crassirostris) is one of the most common gull species in the Northeast Asia and classified as LC (least concern) in the IUCN Red List. The bird has become a useful indicator for marine environmental pollution and habitat disruption, since the human activities impacted marine environments. Here we show that the black-tailed Gull has 6 haplotypes and some rare haplotypes are locally limited implying that the bird may not disperse far. This study may be the first report on population genetic study of Black-tailed Gull in Korea and could be used as the baseline data for monitoring and genetic study on the bird as an environmental indicator.

• Journal of Wetlands Research
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• v.7 no.4
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• pp.81-88
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• 2005

A total of 14,034 individual birds, 11 orders 21 families, were observed during the four year study periods from 2001 to 2004 winter season on the lower Taehwa river. In 2001 the species was the highest with 48, and then the lowest with 31 in 2004. Population was peaked with 11,991 in 2002, but the lowest number was 3,476 in 2004. The birds recorded more than 5% relative dominance were Aythya ferina (6,946), Corvus frugilegus (1,643), Larus ridibundus (1,193) and Larus crassirostris (805), and their total numbers were 10,587 individuals, 75.4% of the total individuals. For wintering birds protection on Taehwa river, it is necessary to make feeding site, shelter and buffer zone along the river. Establishment of wall or forest for absorbing sound and light should be created between road and flood plain. Besides these artificial facilities, the public awareness of citizens will be the most important thing to protect birds. Moreover, it is necessary to prepare conservation and management measures for the river bed where Taehwa river meets Dong river where the birds used bamboo forest($2{\times}0.1km^2$) for breeding and roosting.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.155.2-155
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• 1998

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 1998.04a
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• pp.39.1-39
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• 1998

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.134.3-134
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• 2003

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.132.1-132
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• 2003

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.134.2-134
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• 2003

No Abstract, See Full Text