Spacing patterns and territoriality of the stone marten P. Genovesi, I. Sinibaldi, and L. Boitani Abstract: Sixteen stone martens (Ma'rres ,foina) were intensively radio-tracked in central Italy in order to assess their spacing patterns. Home-range sizes and distances travelled per night were analysed with respect to sex, age, season, and habitat. Intrasexual territoriality is confirmed for the species; home-range edges appeared to be determined by the dispersion of neighbours' territories. Home-range size was positively correlated with the presence of woodland (less abundant and more dispersed resources). Males travelled longer distances than females, although home-range sizes did not differ significantly by sex; males did not move more during the rutting season than in other seasons. Subadults were tolerated by adults for varying periods, then in some cases they started an exploring phase before settling into a vacant territory. Stone martens' spacing patterns were affected by sex. age, social interactions, and resources. In particular, social patterns appear to be a key influencing factor, as territoriality, parental behaviour, mating interactions, and dispersal of young can account for site fidelity, dispersion of home ranges. and distance travelled. In particular, our data indicate the importance of the extended relationship between the mating pair, which is probably related to male parental investment, in determining the spacing patterns of the species. Rdsumd : Le depistage intense de seize Fouines (Martus fouinu) porteuses d'emetteurs radio a ete entrepris dans le but d'evaluer les patterns d'espacement en Italie centrale. La taille du domaine vital et 1es distances parcourues chaque nuit ont ete analysees en fonction du sexe, de I'ige, de la saison et de I'habitat. La territorialite intrasexuelle est confirmk chez cette espece; les limites du domaine semblent determinees par la dispersion des territoires des voisins. La taille du domaine est en correlation positive avec la presence de boises (ressources moins abondantes et plus dispersees). Les miles se deplacent sur de plus longues distances que les femelles, bien que la taille des domaines ne differe pas significativement chez les miles et les femelles; les miles ne se deplacent pas plus durant la saison du rut qu'au cours des autres saisons. Les individus subadultes sont tolkres par les adultes pour des periodes de duree variable puis, en certains cas, ils se mettent a explorer avant de s'ktablir dans un territoire vacant. Les patterns d'espacement des fouines semblent affectes par le sexe, I'Lige, les interactions sociales et les ressources. En particulier, les interactions sociales semblent constituer un facteur determinant, puisque la territorialite, le comportement parental, les interactions au moment de la reproduction et la dispersion des jeunes peuvent expliquer la fidelite a un site, la dispersion des domaines vitaux et la distance parcourue. Nos donnees indiquent surtout I'importance d'une relation prolongee entre les partenaires d'un couple dans l'etablissement des patterns d'espacement d'une espece, sans doute 2 cause de I'investissement parental important du mile. [Traduit par la Rkdaction] Introduction Spacing patterns of Martes populations can be affected by several factors, including body size, sex, and resource dispersion (for a review see Powell 1994). In martens, the female's home-range size is positively correlated with body size (American marten, Martes americuna; Buskirk and McDonald 1989), and males have larger home ranges than females (American marten, Powell 1994; Eurasian pine marten, Martes martes, Balharry 1993). In the American marten, Thompson and Colgan (1987) found a relationship between home-range size and habitat, owing to variation in I Received January 14. 1997. Accepted June 1 1. 1997 I P. Genovesi.' Istituto Nazionale per la Fauna Selvatica, Via Cat Fornacetta 9, 40064 Ozzano Emilia (BO), Italy. I. Sinibaldi and L. Boitani. Department of Animal and Human Biology, University of Rome "La Sapienza," Viale Universita 32, 00185 Rome, Italy. I ' Author to whom all correspondence should be addressed (e-mail: infspapk@iperbole.bologna. it). Can. J. Zool. 75: 1966- 1971 (1997) prey availability in the habitats considered. For the same species, Katnik et al. (1994) suggested that energy require- ments related to food availability represented the main factor affecting territory size for both males and females. Spatial behaviour is also influenced by social ecology and consequently by age. In fact, most martens generally show intrasexual territoriality (sensu Powell 1979) (Balharry 1993; Powell 1994), and social rank is thus another factor expected to affect spacing patterns. Sandell ( 1989) proposed that in all solitary carnivores, whereas food is the main factor affecting females' dispersion, males tend to also disperse with respect to females, as the males try to gain access to the highest pos- sible number of females in order to maximise their fertilisa- tion rate. Since social rank is positively correlated with age, different spacing behaviours are expected for territorial adults, transients, and young. In the Eurasian pine marten, for example, adults have larger home ranges than subadults (Balharry 1993). Social ecology could also affect internal use of home ranges: according to Sandell's hypothesis, use of the home range should vary with sex, and sexual differences could be 1997 NRC Canada