Foraging bird abundance on canopy trees within shade-coffee farms

Abundance of foraging birds of each species for each observation period. country: country data was collected in (Nicaragua or Colombia); year: year data was collected (2015 or 2016); observer: observer initials; date_format: date of observation; juldate: julian calendar date; observation_num: observation number; treeID_format: individual code to identify trees; observationID: unique identifier; treesp: tree species common name (see paper for species names); time_format: time of observation; bird_sp: bird species common name (Colombia) or code (Nicaragua); num_birds: count of individuals; migratory_insectivore: binary dummy variable for primarily insectivorous migratory species; notes: miscellaneous notes; canopy_volume: canopy volume (meters cubed); scale_volume: scaled canopy volume with mean zero

各观测时段内各觅食鸟类物种的个体丰度。country: 数据采集所在国家（尼加拉瓜或哥伦比亚）; year: 数据采集年份（2015或2016）; observer: 观测者姓名首字母; date_format: 观测日期; juldate: 儒略历日期; observation_num: 观测序号; treeID_format: 用于识别单棵树木的个体编码; observationID: 唯一标识符; treesp: 树木物种通用名称（物种学名详见论文）; time_format: 观测时间; bird_sp: 鸟类物种通用名称（哥伦比亚数据集）或物种编码（尼加拉瓜数据集）; num_birds: 鸟类个体数量统计值; migratory_insectivore: 针对主要食虫性迁徙鸟类的二元虚拟变量; notes: 杂项备注; canopy_volume: 树冠体积（单位：立方米）; scale_volume: 经均值中心化的标准化树冠体积