Ecological approaches to species recognition in birds through studies of model and non-model species

All birds propagate sexually and reproduction critically depends on individuals' abilities to secure matings within their own species. Discrimination of conspecifics from heterospecifics may also improve fitness in many additional social contexts, including foraging, roosting, migrating, and antipredator behaviour, that are separate from mating. Understanding the developmental basis of any universal behavioural trait, including avian species recognition, may benefit from the development and use of model systems where genetic, ontogenetic, and environmental variables can be identified and controlled. Indeed, extensive initial progress in the study of social affiliation and preference in birds was made based on laboratory studies of a handful of precocial and altricial species, especially in the context of filial and sexual imprinting. This research helped to establish ontogenetic paradigms and generated testable hypotheses for further laboratory and field studies of both avian and non-avian taxa regarding the importance of imprinting and early experience in the development of social choice. Here, we review and interpret the findings of species recognition studies in the context of ecological variation in avian taxa across gradients of parental care strategies, including "non-parental" megapodes and brood parasites. We highlight the benefits of a recent paradigm shift to describe the importance of non-imprinting based recognition mechanisms in the study of avian recognition systems and argue to include the full range of life history variation that birds exhibit in order to confirm or reject long-standing hypotheses regarding the constraints and flexibilities of avian cognitive architecture and their contributions to species recognition systems.