台中霧峰地區大赤鼯鼠之活動範圍與巢位利用

Abstract

大赤鼯鼠(Petaurista philippensis grandis)為臺灣中低海拔常見之大型鼯鼠，以往本種生態與繁殖研究多以中海拔原始林或人工針葉林為主，較少探討低海拔淺山與聚落附近族群的之生態習性。本研究針對人為活動較頻繁區域進行大赤鼯鼠的生物學研究，以探討該物種於淺山地區的活動範圍、巢位利用與生殖等相關議題。研究樣區位於台中市霧峰區，於該區果園、檳榔園與造林地內設置巢箱112個，捕捉使用巢箱的大赤鼯鼠進行無線電追蹤。於2010年至2011年間，以網具捕捉19隻大赤鼯鼠，並將其中12隻雄鼠與5隻雌鼠戴上無線電發報器。無線電追蹤資料顯示，雄鼠月平均活動範圍為15.90±3.17公頃(95%MCP, n=7)，大於雌鼠月平均活動範圍7.60±1.98公頃(95%MCP，n = 3)，但無顯著差異(p = 0.0538, Mann–Whitney U test )。活動範圍於同性與異性間皆有所重疊，重疊區域多為巢箱設置區，同時亦為雌鼠繁殖的區域。另就巢位利用而言，大赤鼯鼠利用6種不同類型的巢位，其中洞穴型的巢位有天然樹洞、巢箱和岩洞，而露天型的巢位為樹枝巢、藤蔓叢和棕櫚科頂端葉基等。分析巢位利用結果顯示，雌性個體對巢箱的使用率為53.33%，高於雄性個體的21.63%。且一隻雌鼠曾占用的巢箱數量多於雄鼠(雄性=5.25個，雌性=11.25個)，而雄鼠使用的其他巢位類型則多於雌鼠(10.5個＞4.5個)，兩性間所佔用的巢位數量無顯著差異(p=0.932, Mann–Whitney U test)。另就兩類型巢位而言，雌鼠利用洞穴型巢位的數量與比例較雄鼠高，但無顯著差異(p=0.508, Mann–Whitney U test) )。由雌鼠較高之巢箱占用率，且巢箱遮風蔽雨之功能性較其他類型巢位佳，以及樣區內樹洞資源少，推測巢箱應為本樣區內鼯鼠較偏好的巢位。Indian giant flying squirrel Petaurista philippensis grandis is the well-known and the most studied flying squirrel in Taiwan. However, there are few studies about behavior and ecological habitat of this species in lowland Taiwan. In this study, we investigated the behavior of this species in lowland to know its home range , nest use, and breeding performance. We set up 112 nest boxes at orchard, betel-nut palm, and plantation in Wufeng Taichung. Nineteen flying squirrels were captured in nest box between 2010 and 2011. Twelve male and 5 female squirrels were tagged with radio transmitter for tracking. The results show that mean monthly home range size of male (15.90±3.17 ha, 95%MCP, n=7) is larger than female (7.60±1.98 ha, 95%MCP, n=3; p= 0.0538, Mann–Whitney U test). Home range size of flying squirrels overlap between sexes, males, and females, and the overlapped area almost locate at the nest boxes region that female breed there. Six types of nest are used by flying squirrels, including tree cavity, nest box, and rock cave of “cavity type nest” and drey, vine nest, and palm nest of “external type nest”. Occupancy ratio of nest box in females (53.33%) is higher than that in males (21.63%). And females occupied more number of nest boxes than males (male=5.25, female=11.25). On the contrary, males occupied more number of other type nests than females (male=10.5, female=4.5, p= 0.932, Mann–Whitney U test). Otherwise, females occupied more number of cavity type nest than males (p=0.508, Mann–Whitney U test). The high probability of nest boxes occupancy by females might be due to the breeding need of females to care for their young in a safer nesting site. And nest boxes may meet the criteria because they are relatively weatherproof in comparison with other nest types.