SHORT COMMUNICATION Copulatory behaviour in the colonial Eurasian Griffon vulture Gyps fulvus Antoni Margalida Æ Joan Bertran Received: 25 May 2008 / Accepted: 18 May 2009 / Published online: 12 June 2009 Ó Japan Ethological Society and Springer 2009 Abstract We examined copulation patterns and associ- ated sexual behaviour in the colonial Eurasian Griffon vulture Gyps fulvus during the pre-laying period. Eurasian Griffon vulture pairs conducted an average of 71.7 copu- lation attempts per clutch, with an average copulation frequency of 1.2 copulation attempts per day. Low copu- lation frequencies compared to other raptors and absence of mate-guarding suggest that this species does not possess adaptive behaviour aimed at increasing paternity assurance. However, the gradual increase in copulations during the fertile period is consistent with the sperm competition hypothesis. Keywords Eurasian Griffon vulture Á Extra-pair copulation Á Gyps fulvus Á Sperm competition Introduction In birds, frequent copulations constitute a paternity-assur- ing strategy when males are unable to guard their females during the fertile period. The aim is to reduce the risk of extra-pair copulations (EPCs) that may lead to extra-pair paternity (Birkhead et al. 1987; Birkhead 1988; Birkhead and Møller 1992). This strategy is often found in colonial bird species, in which mate-guarding is not practical, and EPCs are more frequent (Møller and Birkhead 1993). Because higher breeding densities also imply more opportunities for EPCs and sperm competition, the risk of extra-pair fertilizations (EPFs) is supposedly higher in colonial than in solitary bird species. To reduce the risk of cuckoldry, males may adopt one or both of two strategies: (1) guard their mates closely, as has been described in other vulture species (Dona ´zar et al. 1994; Bertran and Margalida 1999) or (2) copulate frequently during the fertile period (Birkhead and Møller 1992). In accordance with the paternity-assurance hypothesis, colo- nial raptors should copulate more frequently than solitary species (Birkhead et al. 1987; Møller 1987), and a higher presence of males (mate-guarding) during the fertile period would be expected. The Eurasian Griffon vulture Gyps fulvus is a cliff-nest- ing, socially monogamous colonial species that may nest in large colonies of over 150 pairs (del Hoyo et al. 1994). Both sexes incubate the eggs and feed the chicks with an equal division of labour during the breeding season (Xirouchakis and Mylonas 2007). However, descriptions of the amount of time females remain unattended during the fertile period, which would test the mate-guarding hypothesis, are non- existent, and even published behavioural studies on sexual activity in vultures are very scarce (Dona ´zar et al. 1994; Bertran and Margalida 1999; Xirouchakis and Mylonas 2007). We report here our study of the copulation frequency and behaviour associated with sexual activity in the Griffon vulture during the pre-laying period. Methods Data for this study were collected during a single breeding season (1998–1999) in the Alta Ribagorc ¸a (central Prepy- renees, north-east Spain, 42.35°N, 0.74°E). Observations were conducted between November 1998 (when the Pyrenean Griffon vulture population initiates its sexual A. Margalida (&) Á J. Bertran Bearded Vulture Study and Protection Group, Apdo. 43, 25520 El Pont de Suert, Lleida, Spain e-mail: margalida@inf.entorno.es 123 J Ethol (2010) 28:179–182 DOI 10.1007/s10164-009-0169-5