Incubation and hatching periods in a Mediterranean Great Tit Parus major population

Capsule The onset of incubation relative to clutch completion is highly variable in Great Tits Parus major, and has important consequences for the duration of the incubation and hatching periods.Aim To investigate when incubation starts relative to clutch completion, its effects on the length of the incubation and hatching periods, and which proximate factors affect all of these traits.Methods We used data from a Great Tit population in Eastern Spain collected over 15 years. Periodic visits to the nests (daily at some stages) allowed the determination of breeding parameters of interest. General linear models were used for analyses.Results On average, incubation started the day of laying of the last egg and lasted 13.2 days. The hatching period lasted 1.7 days. Incubation started earlier relative to clutch completion as temperatures during the laying period were higher and as clutch size increased. The incubation period was shorter if incubation started later relative to clutch completion. Hatching asynchr...