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Nest = Identity of nest box
Idfemale = Identity of female
Year = 1 denotes 2010 and 2 denotes 2011
Date = The date of female body temperature measurement, 1 = 1 May
Femtemp = Female body temperature
Ambientnight = Ambient temperature during the night of female body temperature measurement
Boxnight = The temperature within the nest box
Day = The age of the nestlings when the female body temperature was measured
Exp = Experimental category; 1 = enlarged, 2 = control, 3 = reduced broods
Brood = Number of nestlings in the brood
Femalemass = mass of the female at nestling age 14 days
Femage = female age; 2 = a female in her second calendar year etc.
Nestl mass = The mean mass of the nestlings in a brood
Femaletars = tars of the female at nestling age 14 days
Fem cond = Female condition estimated as the residual mass from the relationship between mass and tarsus length of the females

Nest（巢箱标识）：巢箱的唯一识别编号
Idfemale（雌性亲鸟标识）：雌性亲鸟的唯一识别编号
Year（年份）：取值1代表2010年，取值2代表2011年
Date（测量日期）：雌性亲鸟体温的测量日期，其中取值1代表5月1日
Femtemp（雌性体温）：雌性亲鸟的身体体温
Ambientnight（夜间环境温度）：雌性亲鸟体温测量当日夜间的环境气温
Boxnight（巢箱内温度）：雌性亲鸟体温测量当日夜间巢箱内部的温度
Day（雏鸟日龄）：开展雌性亲鸟体温测量时，雏鸟的日龄
Exp（实验分组）：实验类别，其中1代表扩群组，2代表对照组，3代表减群组
Brood（窝雏数）：当前巢窝内的雏鸟总数量
Femalemass（雌性亲鸟体重）：雏鸟日龄为14天时雌性亲鸟的体重
Femage（雌性亲鸟年龄）：雌性亲鸟的年龄组别，其中2代表处于第二个日历年度的雌性个体，其余以此类推
Nestl mass（雏鸟平均体重）：当前巢窝内所有雏鸟的平均体重
Femaletars（雌性亲鸟跗跖长度）：雏鸟日龄为14天时雌性亲鸟的跗跖长度
Fem cond（雌性亲鸟身体状况）：基于雌性亲鸟体重与跗跖长度的回归残差估算得到的身体状况指标