秦岭羚牛中独栖现象的初步观察

在群栖的秦岭羚牛种群中，存在着少数单独活动的羚牛，称为独牛。野外见到独牛５０只次，占见到羚牛总数的４５９％。独牛中有老年雄性个体、青壮年雄性个体、雌性个体、亚成体和幼仔。在繁殖季节独牛出现的次数最多，其中大部分是雄性个体，也有雌性个体。与羚牛的四川亚种不同，在秦岭亚种中很少见到公牛集群的现象。羚牛种群中独牛的形成主要与繁殖有关，同时还与疾病及防御迁移有关。独牛在不同季节、不同生境内均可见到，绝大多数老年独牛活动区域的海拔高度低于集群的羚牛活动的高度。老年独牛在离群活动后，其活动节律与群体中的雄牛有一定的差异，这种差异在夜间的活动时间和活动率方面表现得更加明显。

PRELIMINARY OBSERVATION ON THE PHENOMENA OF SOLITARY INDIVIDUALS IN GOLDEN TAKIN(BUDORCAS TAXICOLOR BEDFORDI)IN QINLING MOUTAIN RANGES

Golden takin (Budorcas taxicolor bedfordi )naturally appears in groups, but a few individuals of them can be observed as solitary ones. Fifty individuals of solitary takins were tallied from March to November 1996, which were counted 4 59% of the total takins observed in the field. Takins of any sexes and ages could be a solitary one, adult males both of old age or in a strong body condition, adult females, sub adults in both sexes, and even calves were found alone. Solitary ones were more likely to be seen in summer when takins were in heat. Majority of the solitary takins observed in the breeding season was adult males, but solitary adult females could also be found. Both of them were in a very good body condition. It was hardly to find group formed only by males in Qinling mountain ranges, while it was seen quite often in the subspecies of Tibetan takin (B t tibetana) . We strongly suggested that some adult males in a good body condition would likely be alone in breeding season when they moved between groups and try to get more mating opportunities. They would be aggregated in groups again after the breeding season was over. Animals which were ill or weak might be left alone if they could not keep up with groups when they made a move of feeding or escaping . Solitary takins could be found in any season and in any kinds of habitat. Most solitary ones in old age were often found in areas of lower elevation. Two males were collared in the study area (M1 and M2) . M2 was old and alone, M1 was strong and associated in a group. Time budget of the two radio collared takins in July indicated that active rate of M1 and M2 was not significantly different in the 24 hours period, but it was different at night for the two takins. Active signals could be received at day and night for M1, but M2 was very active in the day time and almost spent all the time on resting at night.