Following the rules? Differential life-stage responses of biometrics across four decades of warming in a songbird population

This study aims at testing how biometrics of eggs, nestlings and adults covary with ambient temperature in a

population of Great tits (Parus major) living in Sagunto (Spain) during 4 decades. 

The variables below, followed by a brief description,  are used in the analysis:

BAND: The individual identification number attributed to each subject involved in the study

CAPTURE_DATE: the date (YEAR-MONTH-DAY) when an adult bird was captured

NEST_ID: the unique identification umber of the nest of origine to which eggs, nestlings or adults belong.

EURING: age of the individual attributed based on the EURING criteria

AGE: age of the individual in years

SEX: categorical variable with two levels indicating whether a subject is M=male or H=female

WC: wing chord length in cm

TAR: tarsus length in cm

MASS: mass of the subject in g

STAGE or LIFE_STAGE: life stage of the subject either egg, nstl (nestling), or ad (adult)

YEAR: year when the measurements were collected

T_YEARLY: mean ambient temperature for a given year

CLUTCH_SIZE: number of eggs in the nest once the laying process was completed

L: egg length measured in mm

H: egg height measured in mm

VOLUME: volume of the egg calculated with the formula reported in the paper

F_MASS: mass of the females captured, measured in g

SPRING_T: mean spring temperature between March 21 and June 21

Total_Clutch_Mass: mass of the entire clutch obtained adding the mass of each egg iun the clutch. Mesured

in g.

TMED: daily mean ambient temperature obtained averaging TMAX (maximum daily temperature) and

TMIN (minumum daily temperature).

MEAN_LATE_SPRING_TEMP: mean ambient temperature for the period between March 21 and July 21.

BS: brood size. Number of nesltings in the nest at the time of measurements.