Age dependent reproductive effort in great tits

I measured daily energy expenditure (DEE) of great tits raising offspring using doubly labelled water in three different years (1989–1991). Independent of sex, DEE declined with age. Although DEE declined with age, provisioning rate was independent of age in the same data set, and neither did age significantly affect the number and growth of offspring. Data uploaded here include the DEE estimates and other relevant variables used in the accompanying publication (age, year, sex, ambient temperature)., , # Data underlying \"Age-dependent reproductive effort in great tits\"

## Author: Simon Verhulst

### Documentation of data file \"age_and_dee.csv\"

When a nest box number appears twice in a given year, this means DEE of both parents was measured. Empty cells indicate missing data.

* AGE : Age in years
* Feeds_hour: number of feeds per hour of the focal bird
* BROODMASS1: mass in grams of the brood the time of doubly labelled water injection
* BROODMASS2: mass in grams of the brood when collecting the second (=final) blood sample
* DEE: daily energy expenditure in kiloJoules
* Mass1: mass in grams of the focal bird at the time of double labelled water injection
* Mass2: mass in grams of the bird when taking the second (= final) blood sample
* Nestling_Mass: mean nestling mass in grams
* Year: year data were collected
* Clutch_reduced: 0 = control, 1= 50% of eggs replaced with artificial eggs
* NF: number of young fledged
* NestBox: unique number of nest box
* Male: 0= female, 1=male
* Tem...,