Script and data for "Interference competition with an invasive species as potential driver of rapid extinction in an island-endemic lizard"

Competition between native and alien species is often described as a main driver of biodiversity loss. Nevertheless, there is limited evidence of animal declines and extinctions actually determined by competition. The Aeolian lizard, Podarcis raffonei, is critically endangered because it suffered dramatic declines and extinctions throughout its range. Competition and hybridization with invasive Italian lizards, Podarcis siculus, have been proposed as a driver of the shrinkage of Aeolian lizards, still the mechanisms underlying their decline remain poorly resolved. We used observations of behavioral encounters, combined with morphological data and robust species identification based on genomics, to test whether agonistic interactions with the invasive Italian lizard can explain the competitive exclusion and rapid decline of the native Aeolian lizard while accounting for hybridization.We provide:Data on the morphological features of tested individuals (weight; snout-vent length and three parameters representing head size: maximum head width; maximum head height and pileus length)Data on the bite tendency of lizards (bite tendency; bite lengths) against neutral items (wood sticks)Data representing the outcome of the agonistic interactions between individuals in experimental terraria (results for 161 behavioural encounters: 65 between two Aeolian lizards, 23 between two Italian lizards and 73 between the two species)The scripts used to analyse the data