台灣中部褐鷹鴞Ninox scutulata捕食大型昆蟲類食餌之研究

Large Insect Diet of the Brown Hawk Owl Ninox scutulata in the Central Taiwan

A total of 2,269 remains of large insects discarded aside by the brown hawk owl Ninox scutulata in its noctural feeding were collected at intervals of two weeks under the road lamps in three areas of the peripheral hills of the Central Mountain Range at elevations of 400-700m, November 1999 to December 2001. The results showed that in terms of number of the remains for the study period, insects of the order Coleoptera and Lepidoptera were the most dominant with 844 (37.2%) and 751 (33.1%), respectively. The second dominant group was Homoptera and Orthoptera with 249 (11.0%) and 188 (8.3%). In terms of biomass Coleoptera was the most dominant with a total net weight of 481.1g (37.5%), while Lepidoptera, Orthoptera and Homoptera had 262.9g (20.5%), 253.8g (19.8%), and 204.2g (15.9%). Phasmida, Odonata, Megaloptera, Neuroptera, Lepidoptera, and Homoptera had high utilization rates with98.4%, 97.6%, 97.3%, 96.0%, 93.4%, and 91.4% The above six orders of insects were highly utilized by the owl at levels higher than 90.0% of their body weight. The group with lower rates was made up of Coleoptera and Orthoptera at 73.0% and 70.6%. 研究期間共蒐集2,269個褐鷹鴞捕食大型昆蟲後的食物殘餘，三樣區中以鞘翅目及鱗翅目昆蟲被捕食的數量最多，分別有844（37.2%）與751（33.1%）個食物殘餘。其次為同翅目與直翅目昆蟲，分別有249（11.0%）與188（8.3%）個食物殘餘。褐鷹鴞捕食的大型昆蟲生物量以鞘翅目昆蟲最多，達481.1g（37.5%）。鱗翅目、直翅目與同翅目昆蟲居次，所提供之生物量分別是262.9g（20.5%）、253.8g（19.8%）與204.2g（15.9%）。所有褐鷹鴞捕食的大型昆蟲之中，以竹節蟲目、蜻蛉目、廣翅目、脈翅目、鱗翅目與同翅目的被利用率最高，利用率分別為98.4%、97.6%、97.3%、96.0%、93.4% 與91.4%，這六目昆蟲被利用率均超過90%，可說是被褐鷹鴞利用最澈底的一群。鞘翅目與直翅目昆蟲的被利用率較低，分別只有73.0% 與70.6%。