data departure direction

There are six columns: 1. “year”: This variable indicates the year in which the bird was caught. 2. “season”: This variable indicates whether the bird was caught in spring or autumn. 3. "subsp": This is a factor with two levels. "leu" says that the bird belonged to the leucorhoa subspecies of the northern wheatear and "oen" says that the bird belonged to the oenanthe subspecies of the northern wheatear. 4. "Age.ad": This is a factor with two levels, i.e., "young" and "old". In autumn, "young" means 1st calendar year bird and "old" means that the individual was older than "young". In spring, "young" means 2nd calendar year bird and "old" means that the individual was older than "young". 5. "Sex": This is a factor with two levels. "1" says that the bird was a male and "2" that it was a female. 6. “direction”: This is the departure direction in degree.

该数据集共包含6列字段，具体说明如下：1. "year（年份）"：该变量记录捕获该鸟类的具体年份。2. "season（季节）"：该变量标识该鸟类的捕获季节为春季或秋季。3. "subsp（亚种）"：为二分类因子变量（factor），包含两个水平："leu"代表该鸟类属于北方穗鵖（Northern Wheatear）的leucorhoa亚种，"oen"代表该鸟类属于北方穗鵖的oenanthe亚种。4. "Age.ad（年龄）"：为二分类因子变量，包含两个水平："young"与"old"。在秋季捕获的个体中，"young"指处于第一个日历年的幼鸟，"old"指年龄大于该类别的个体；在春季捕获的个体中，"young"指处于第二个日历年的鸟类，"old"指年龄大于该类别的个体。5. "Sex（性别）"：为二分类因子变量，"1"代表雄性鸟类，"2"代表雌性鸟类。6. "direction（起飞方向）"：该变量以角度为单位，记录鸟类的起飞方向。