摘要
Barn Owl (Tyto alba) pellets were collected from nine locations and two districts of Sindh,Pakistan and 937 prey items were recovered from 619 pellets.Rats/mice (59.6%) were the most dominant food items consumed by the Barn Owl.Shrews (22.3%),bats (1.3%),birds (12.0%),insects (1.3%),frogs (2.2%) and plant materials (1.3%) were found in their diet as well.Study of the pelvic girdle bones of rats/mice,used only for sexing,proved to be a useful device in population dynamics.In the pelvic bone,pelvic symphysis is found only in female rats/mice developed as a result of sex hormones that occur during gestation.Among the diet of rats/mice,males were found to be significantly dominant.Tooth wear patterns on the occlusal surfaces of molariform teeth of the rats/mice were found to provide an effective criterion for establishing age classes of rats/mice.In the present study,adult rats/mice were found to be dominant over sub-adults and old adults.ANOVA showed significant differences in the number of rats/mice and shrews (prey items) and the other prey items/plant materials in the diet of Barn Owls in the district Thatta and district Karachi.Chi-square test disclosed non-significant differences in age and sex categories.
我们从巴基斯坦信德省卡拉奇(Karachi)和塔达(Thatta)两个地区的9个地点共收集仓鸮(Tyto alba)食丸共619个,从这些食丸中发现937种食物种类。仓鸮最主要的食物为大鼠和小鼠(59.6%),还包括鼩(22.3%)、蝠类(1.3%)、鸟类(12.0%)、昆虫(1.3%)、蛙类(2.2%)及植物(1.3%)等其他种类。对大鼠和小鼠的骨盆带骨的分析表明,这一通常仅用以区分性别的结构有助于种群动态的研究。雌性大鼠和小鼠的骨盆骨中具有耻骨联合现象,这是因为在孕期产生性激素而发育形成的。在仓鸮所捕食的的大鼠和小鼠中,雄性个体显著居多。我们发现,大鼠和小鼠臼形齿的咬合面磨损形式是确定它们龄级的一个有效标准。本研究中,成年大鼠和小鼠数量显著多于亚成年及年老个体。方差分析表明,上述两个地区的仓鸮食物中,大小鼠与鼩及其他食物种类在数量上存在显著差异,而χ2检验则表明这两个地区的大小鼠龄级和性别比例均无显著差异。
