食物和季节因素对杂色山雀贮食行为的影响

Effect of food and seasonal factors on the food caching behavior in the varied tit

鸟类的贮食行为受很多因素的影响,其中食物和季节是两个十分关键的因子。采用人工投食的方式研究杂色山雀冬、春季节对松子和葵花籽两种食物的贮食选择,以及食物和季节因素对贮食位点的空间分布和微生境选择的影响。结果发现,杂色山雀优先贮食松子,仅在春季贮食少量葵花籽;主要选择树皮裂缝、灌木根部、草丛、石缝和苔藓下面五种生境进行贮食;其贮食位点的空间分布呈分散状态,集中于投食点100m范围内,密度分布随食物搬运距离的增加而递减。其贮食模式和贮食位点的微生境选择均受季节因素的影响,其中,贮食模式的季节变化可能是受生境中松子这种重要食物可获得性的下降所致,而杂色山雀冬季对树皮裂缝的利用率明显高于春季,可能是与冬季的积雪覆盖限制了其对地面贮食点的利用有关。杂色山雀的就近贮食模式可能是为了增加贮食效率,关于不同个体之间贮食位点的差异,以及季节变化对贮食位点的空间分布格局的影响还需进一步研究。

Food caching behavior of birds is influenced by many factors, of which, the type of food and season are the two most critical factors. In this study, we used artificial feeding to explore food selection and food-caching behavior by varied tit （Parus varius） on pine and sunflowers seeds and to reveal the effects of the type of food and seasonal changes on the microhabitat use and spatial distribution of food storage sites. The results showed that varied tit preferred to store pine nuts, but during spring, they also stored a small percentage of sunflower seeds. They preferred to store the food within 100 m from the feeder, in a scattered spatial distribution. The frequency of stored food within 100 m decreased with the increase in the distance between food storage sites and feeders. The microhabitat of food caching included five kinds of locations： bark fissures, shrub＇s root bark, grass, leaf blades, and moss. Both models of food caching and micro habitat selection in varied tits were likely to be influenced by the season. The seasonal variations in the food-caching model was probably related to the decline in the available pine trees in natural environments, while the increasing usage of bark fissures as food-caching habitats was possibly related to the snow cover on the land. In general, varied tits preferred to store food in the proximity of the feeder in order to increase the efficiency of food caching. However, individual variation in the spatial use of food caching and the effect of seasonal variations require further study.