Data from: 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).