Strict mate fidelity and reduced breeding dispersal of widowed Red-billed Choughs Pyrrhocorax pyrrhocorax

Abstract

Capsule Red-billed Choughs showed strict mate and high nest-site fidelity. Changes of mate or nesting site were recorded only in cases of widowhood or collapse of the nesting sites (buildings).Aims To evaluate the relationships between mate fidelity, nest-site fidelity, breeding dispersal and widowhood in a population of Red-billed Choughs.Methods We recorded the rates of mate and nest site fidelity in a ringed population Red-billed Choughs breeding in the Ebro Valley, NE Spain, from 1987–2006.Results We found strict mate fidelity, because no case of divorce was recorded over variable periods of mate pairing, ranging from 2 to 15 years. A proportion of widowed individuals changed nesting sites when re-paired, always establishing nests in places close to their previous nesting sites. We did not find sexual differences in the decision to change nesting site in newly paired widowed individuals, although widowed males tend to show higher site fidelity and lower breeding dispersal distances than females.Conclusions The results support the hypothesis that site fidelity primarily depends on mate fidelity, rather than the contrary. Mate and nest-site fidelity may be species-specific traits that enhance fitness through the shared knowledge of the characteristics and limitations of the mate and the territory in this long-lived species.