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Approaches to the study of territory size and shape are discussed to give an overview of theoretical studies of causes of intraspecific variation with focus on potential for predicting population-level phenomena. Classification of behavioral models of territory size and shape is undertaken. Three approaches, models of interactions among neighbors, focal resident models, and models of interactions between established residents and potential settlers, are considered. A large fraction of studies do not show an effect of food supply on territory size.

Research indicates that female House Sparrows display dominant behavior during winter feeding, and year-round dominant behavior in species with lower prebreeding male dominance. A gradient is predicted for temperate climates and year-round female dominance, and for harsher climates and alternating dominance.

Colonies of Paratrechina flavipes were split into artificial nests, and placed at three different sites. About every 2 weeks for 2 years workers from one of these nests were paired with (related) workers from another nest from the same colony or with (unrelated) workers from a different colony. Aggression between workers of the paired nests varied seasonally. Workers were aggressive to related individuals only during the season whenthe nest was active, but they were always aggressive to unrelated workers. Such variability in aggression within a colony may be due to a seasonal change in the way nestmates are recognized, i.e. workers in active nests may discriminate their nestmates from non-nestmates by using both environmental and genetic odours, whereas when the nest is inactive they use genetic odour alone. The variable recognition mechanism of this ant may be involved in the evolution of more than one nest and one reproductive queen in a colony.

Several sampling surveys are conducted to explain the impact of horning by wildebeest (Connochaetes taurinus) males on the woody vegetation of the Serengeti ecosystem, Africa. The severe damage frequency is shown to be the highest in open grassland and lowest in savanna woodland.

Aggressive interactions in the context of feeding are more common when resources are sparse and/or more patchily distributed (Janson 1985; Barton & Whiten 1993; Sterck & Steenbeek 1997; van Schaik & van Noordwijk 1988). Several studies have analyzed the effects of resource distribution and abundance on the frequency of dyadic interactions, but no studies to date have related the severity of aggression to food resource characteristics. I studied two levels of dyadic aggressive behavior (active and passive) as well as polyadic aggressive behavior during feeding in white-faced capuchins, Cebus capucinus. This study addresses whether resource quality, quantity, and distribution have an effect on the type and quantity of competitive interactions observed. I evaluated the importance of nine ecological and behavioral variables that may influence escalations in food related aggression during a 15 month period. Focal feeding trees (n=700) were observed from the beginning to end of a feeding bout and all dyadic and polyadic aggressive interactions were recorded. These types of aggression are likely to be associated with different risks of further escalation and subsequent costs of time and possible injury. Preliminary analysis indicates that frequency of food-related aggression can be predicted by both ecological and behavioral variables, whereas the type of aggression appears to be influenced mostly by the crown volume and the number of competitors in the feeding tree. These results agree with previous studies on capuchin monkeys and further support our understanding of the role of ecology in affecting primate social structure.