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Abstract Colour polymorphic species often exhibit variation in morphology, physiology, and behaviour among morphs. In particular, dominance status may be signalled by the interaction between behaviour and colour morph. Behavioural traits associated with dominance include boldness, exploration, and aggression, which influence access to preferred habitat, territorial defence, and mate acquisition. In ectotherms, the social structure associated with morphs may result in the exploitation of structural niches differing in thermal quality. Hence, social interactions among morphs may generate concordant variation in thermal preference and environmental temperature. However, few studies have assessed thermal preference variation in colour polymorphic species and its covariation with behaviour. Doing so can provide insight into niche specialization and the maintenance of colour polymorphism in populations. Here, we investigated the patterns of covariation in boldness behaviour, exploratory behaviour, and thermal preference in the tree lizard,Urosaurus ornatus. We assessed trait variation between territorial and non‐territorial male morphs and between orange and yellow female morphs. Boldness and exploratory behaviour were repeatable in maleU. ornatusand bolder individuals were significantly more likely to incur tail loss, a potential consequence of bold behaviour. Territorial male morphs were significantly bolder and more exploratory and preferred higher body temperatures with a narrowerT_setthan non‐territorial morphs. Female morphs did not vary in behavioural or thermal traits. This study highlights behavioural mechanisms that underly ecological niche segregation and variable habitat use between morphs in a colour polymorphic species. 

Abstract Lizards engage in push-up displays to signal dominance and to secure access to important resources. The rate and patterns of push-up displays have been shown to vary based on both biotic and abiotic factors. We investigated push-up display rate in tree lizards,Urosaurus ornatus, to determine contributions from potentially conflicting factors including sex, throat colour, microhabitat usage, social context, and thermal traits. We found that display rate was best described by an interaction between microhabitat and body temperature (T_b). The relationship between display rate andT_bwas significantly different between three microhabitats: sunny dead trees, the inner branches of trees, and tree trunks. We suggest that this variation in display rate is driven by shifts in microhabitat temperature over the course of the day and spatial and temporal adjustments being made depending on the probabilities of being detected by both conspecifics and predators.