Does concealing posture in Collared Scops Owl (Otus lettia) have masquerading function?

• Main Authors: Hung-Chang Chen, 陳宏昌
• Other Authors: Dr. Yuan-Hsun Sun
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/92052234303273752121

碩士 === 國立屏東科技大學 === 野生動物保育研究所 === 101 === Researchers have found that owls would change their body shape from oval to tall and slender while sensing danger. It was hypothesized that the change in body shape would help them avoid attack from predator or mobbing from small birds, yet it has not been tested. We tested the functions of such behavior in the Collared Scops Owls(Otus lettia) using two types of specimens, oval and tall/slender, on the campus of Pingtung University of Science and Technology and nearby forest plantation. A total of 82 persons were asked to search one of the specimens in trees in six minutes. When testing detection by preys, we exposed the two forms of specimens alternately at each site and recorded any mobbing behavior using an event data recorder. We found human testers spent more time looking for the elongated specimen than for the non-elongated one. More people misidentified the elongated specimen as a branch than non-elongated one. The number of mobbing event directed at the specimens is significantly lower for the elongated specimen than for the non-elongated one. We also found birds spending more time searching for the elongated specimen than for the non-elongated one. Chinese Bulbul (Pycnonotus sinensis) is the species which showed the highest mobbing frequency among the 12 species of birds participating mobbing.