Linear mixed effects model to test for early-life paternal care effects associated with father age (years) on offspring telomere length (bp).

Comparison of the effect of the age of the caring father (either the genetic father or the foster father when the clutch was cross-fostered) and the difference of genetic father age and foster father age (difference father ages). Note that the age of the male caring for the clutch, and the age difference between the genetic and the caring father add up to the age of the genetic father.