• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.4
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• pp.87-93
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• 2006

The black-tailed gull chicks, Larus crassirostris, recognize various adult voice signal base on the simple patterns. We investigated behavior change in black-tailed gull chicks through physical manipulation of mew call. They were playback in four situations differing in physical character: 1) frequency manipulation only, 2) duration manipulation only, 3) call intensity(dB) manipulation only, and 4) call interval manipulation only. We observed occurrence of different response of the chicks, which were categorized into two behaviors(hidden and return behavior). The manipulated frequency, duration, and intensity were directly correlated. The chicks exposed to only manipulated call interval(0.5, 1sec) made significantly more hidden and return behavior. Adult black-tailed gull only increased flight time on manipulated call interval. The results suggest that black-tailed gulls use short call interval for alarm signal. The analysis of alarm signal provides an important on basic study of bird strike.