Nest hole age decreases nest site attractiveness for the European Starling Sturnus vulgaris

Abstrakti

I studied whether the European Starling Sturnus vulgaris has a preference for a particular age of their nesting hole in an old deciduous forest in Central Poland. I documented the probability that Starlings bred in natural holes (excavated by Great Spotted Woodpecker Dendrocopos major) of a known age in consecutive seasons. Occupation rates decreased linearly with a holes age. Holes were occupied significantly more frequently in the first year after their excavation then older holes. Experimentally adding old nest material to nestboxes in order to simulate prior occupancy lowered the occupancy rate in a similar manner as observed in the natural cavities. Whereas avoidance of predation risk is the tra-ditional explanation for avoidance of old sites, my results suggest that factors like pres-ence of old nest material (with ectoparasites), and physical deterioration in the holes quality should also be considered.