南京中山植物园鸟类对香樟果实（种子）的取食

Bird Feeding on the Fruits(Seeds) of Camphor Trees in Nanjing Zhongshan Botanical Garden, China

香樟(Cinnamomum camphora)是亚热带地区广泛分布的常绿阔叶树种,其果实数量多、果期长,可为鸟类提供大量食物资源。2018年11月至2019年2月,借助Safari 10×26变焦双筒望远镜,采用焦点扫描法对南京中山植物园内访问香樟果实(种子)的鸟类行为进行观察,详细记录鸟类的种类、取食基质、取食次数、取食时间、取食数量和取食方式等信息。研究期间有效记录达48 d,累计记录到27种鸟类1021次取食香樟果实(种子)行为,存在2种取食基质(地面和树上)和3种取食方式(整吞果实、啄食果肉和取食种子)。T检验显示,不同鸟类对香樟果实(种子)的取食次数存在显著差异(t=3.096,df=26,P<0.01);不同月份间鸟类对香樟香樟果实(种子)的平均访问只数、平均取食次数、平均取食时间和取食数量均存在极显著差异(P<0.001)。白头鹎(Pycnonotus sinensis)、乌鸫(Turdus mendarinus)和灰喜鹊(Cyanopica cyanus)是访问次数及取食量最多的3种鸟类。单因素方差分析(One-way ANOVA)表明,上述这3种鸟类的取食数量存在极显著差异(F3,598=25.219,P<0.001)。按照时间统计,11月份访问的鸟类种类和数量最多,1月份鸟类的取食次数、时间和数量最多。鸟类的形态特征(体重、体长和嘴峰长)与取食数量呈显著正相关,其中,体重和体长对取食数量的影响比嘴峰长的影响更显著,但嘴峰长影响鸟类对果实的取食方式。在鸟类常活动和停歇的树木下方地面往往散落着较多表面洁净、无果肉包裹的香樟种子,且园内人工林和自然更新林地可见许多香樟幼苗,表明鸟类对香樟具有潜在传播作用。

The Camphor Tree(Cinnamomum camphora)is an evergreen broad-leaved tree species with abundant fruits and a long fruit period,which is widely distributed in subtropical areas.With Safari l0×26 zoom binoculars,the focus scanning method was adopted to observe the bird behavior of visiting Camphor trees in Nanjing Zhongshan Botanical Garden,China,from November 2018 to February 2019.The information of bird species,foraging substrates,foraging frequency,foraging time,foraging amount and foraging methods were recorded.For the 48 effective days of observation,a total of 1021 foraging behavior of 27 species of birds were recorded with 2 foraging substrates(ground and tree)and 3 foraging methods(swallow the fruits,pecking at pulp and seed predation)(Table 1).One-Sample T-test showed that there were significant differences in foraging frequency among different bird species(t=3.096,df=26,P<0.01).There were significant differences in the average number of visits,average foraging frequency,average foraging time and foraging amount between birds in different months(P<0.001,Fig.1).Light-vented Bulbul(Pycnonotus sinensis),Chinese Blackbird(Turdus mendarinus)and Azure-winged Magpie(Cyanopica cyanus)are the three types of birds with the most visit and foraging amount(Fig.2).One-way ANOVA showed that there were significant differences in foraging amount among the three species(F3,598=25.219,P<0.001).In terms of time,more species and quantity of birds visited in November in comparison with those in other months,and the foraging frequency,time and amount on the fruits in January were the largest.The morphological characteristics(body weight,body length and bill length)of birds were positively correlated with the foraging amount of the fruits(Fig.4).Effects of body weight and body length on the foraging amount were more significant than that of the bill length,but bill length could affect the feeding methods significantly(Fig.3).Many seeds with clean surface and no pulp wrapped were found under the trees acting as roosting site of birds.Many Camphor seedlings of can be seen in plantations and natural regeneration woodlands,which indicates that birds may play a role in seed dispersal of Camphor trees.