Innovative problem solving in birds: a cross-species comparison of two highly successful passerines

Macro-ecological comparisons have repeatedly demonstrated that the taxonomic distribution of foraging innovations coincides with the ability to adjust to novel and changing environments. We sought to obtain experimental support for the link between innovative foraging and opportunism by measuring the innovation abilities of two highly successful passerines on the east coast of Australia with very different success strategies. The ecological success of the introduced Indian myna, Acridotheres tristis, has been linked to its ability to occupy opportunistically an ecological niche that most natives cannot, whereas the native noisy miner, Manorina melanocephala, owes its success to its ability to aggressively outcompete other avian species. Indian mynas were significantly more neophobic than noisy miners. Yet, when tested on a range of innovative foraging tasks, Indian mynas consistently outperformed noisy miners. The ability to use the beak in a greater range of ways, and more flexibly, was highly repeatable in Indian mynas, and underpinned their superior problem-solving performance. We discuss the results in the light of potential methodological influences, but also the idea that necessity may facilitate innovation not only in less competitive individuals, as is documented in the literature, but also in species with less competitive lifestyles.