Pre-fledging survival in a Yellow-legged Gull Larus michahellis population in northern Iberia is mostly determined by hatching date

Abstract

ABSTRACTCapsule: Pre-fledging survival in a Yellow-legged Gull Larus michahellis population in northern Iberia is negatively correlated to hatching date.Aims: To explore which factors have more importance in determining the pre-fledging daily survival rates in a Yellow-legged Gull population from northern Iberia. Specifically, we tested for the effect of hatching date and order, body size and condition and meteorological conditions on pre-fledging survival.Methods: Cormack–Jolly–Seber models with mixtures were used to model daily survival rates.Results: Daily survival rates were mostly negatively affected by hatching date.Conclusions: Hatching date was the most important factor affecting survival of chicks during the pre-fledging period in a Yellow-legged Gull colony from northern Iberia.