Mixed model selection analysis of effects of laying date (LD) and mean-centered spring temperatures (TEMP) on the number of offspring recruited to the breeding population each year.

Analysis is based on a total of 3,852 records from 2,394 different individuals over a 35-year period (1973–2007). The models were fitted in ASREML-R using a Poisson error structure (log link function) with individual identity and year included as random effects. Significance of fixed effects was assessed based on their Wald test statistics, distributed as χ2 each with 1 d.f.