Size and location of territories have important fitness consequences for breeding males in many species, including lizards. Australian Water Dragons (Intellagama lesueurii) are an interesting study system in which to examine socio-ecological aspects of territory size and male behavior because, despite their large body size, these lizards form dense aggregations within urban riparian habitats. In one such population, we found that males defended territories smaller than have been reported for most other large lizards. Surprisingly, smaller males defended larger territories, but larger territories did not increase access to females. Instead, territory size was negatively correlated with conspecific density, including females, which in turn was highest near a creek that provided abundant prey and refuges. That is, territories were smaller in sites offering more resources for reproduction, feeding, and predator evasion. The relative proportion of displays males gave during contests with rivals did not vary within the reproductive season. However, male travel and the context of stereotypical head displays showed a surprising pattern of seasonal variation. As the season progressed, males increased the proportion of displays to females, but decreased the proportion of undirected territorial advertisement displays. Because Water Dragons are long-lived and philopatric, increased display during interactions with postbreeding females may enhance mating opportunities in future reproductive seasons.