Data from: Do environmental conditions experienced in early life affect recruitment age and performance at first breeding in common goldeneye females?

Environmental conditions experienced early in life may have long-term
impacts on life history traits and reproductive performance. We
investigated whether ambient temperature experienced during the first two
to four weeks of life and weather severity during the first two winters
affected recruitment age and relative timing of breeding in the year of
recruitment in female common goldeneyes (Bucephala clangula). Our sample
consisted of 141 female recruits hatched in a study population in central
Finland between 1985 and 2013 and captured later as breeders. About 56% of
the recruited females bred for the first time when 2 years old (range 2-6
years). Individuals facing colder ambient temperatures during the first
two to four weeks posthatch or more severe winter conditions during the
first two winters did not recruit at an older age. Nor did maternal
characteristics, relative hatch date or nest site availability affect
recruitment age. For females that recruited at 2 years old, the date of
first breeding was usually late relative to the population mean that year
(mean difference 6.9 days, range -7 to 21 days). Our results suggest
developmental buffering enables female goldeneye ducklings to mitigate the
impacts of adverse environmental conditions experienced during the first
weeks of life, at least in terms of first breeding.