Flying into the trap: personality traits and capture biases in a highly successful avian invader, the common myna. (#478)
Over the last decade, animal personalities - correlated suites of behavioural traits – have been shown to be an important force in shaping ecological patterns and processes. In the context of ecological invasions, it is thought that species with a large array of different personalities within their populations have the greatest chance of becoming ecological invaders when introduced to novel environments. The diversity of personalities within invasive species’ populations is not only central to understanding their invasion success, however. It is also central to predicting the long-term effects of invasive species management.
The common (Indian) myna (Acridotheres tristis) is a highly successful worldwide invader that shows repeatable individual differences in neophobia, exploration and behavioural flexibility. Invasive to Australia, the species is the target of increasing control efforts. Evidence is accumulating that in areas with high levels of management, however, trapping success has decreased beyond what might be expected by a simple reduction in bird numbers, suggesting that some populations are showing compensatory responses to this anthropic predation pressure.
In this study we explored whether selective removal of individuals with more ‘trap-friendly’ personalities, including a high propensity for exploration and boldness, might explain why populations are becoming more difficult to trap. We captured 50 common mynas using one of two methods: 1. a widely-used walk-in baited trap which required the birds to explore a large cage-like structure and enter it through small channels; 2. a discreet spring-loaded net which was placed in proximity of a large feeding patch. Netted and trapped birds were tested under captive conditions on a range of personality tests to identify differences in exploration, boldness, fearfulness, social behaviour, anti-predator responses and innovation. Our pattern of findings will be discussed in the light of implications for invasive species management and animals’ ability to adjust to anthropogenic environmental change.