Alarm calls and referentially in Australian magpies: Between midbrain and forebrain, can a case be made for complex cognition?

Abstract

The ability to communicate intentionally and referentially about predators by issuing specific and unique alarm calls per predator type, usually considered indicative of forebrain activity, is generally regarded as evidence of complex cognition. However, the neurobiology of such expressions is not well-understood and the relationship of song to alarm calls is not clear. In the very few studies of brain activity in calls of non-songbirds and songbirds so far, it was found that it is only the midbrain that is involved in the production of calls. The paper argues that such midbrain activity, even in so-called referential signalling, may have been misconstrued as higher cognition when, in fact, it may be merely indicative of a well-preserved (even 'clever') midbrain survival mechanism of prey species, and may be based on instantaneous 'non-thinking' activities of the midbrain. This does not rule out that, in specific species of songbird and in specific types of calls, the production of alarm calls may indeed involve activity and interaction of nuclei in midbrain and forebrain. Such a possible interaction in the production of vocalisations (unlearned and learned) has also been shown in some songbirds, including the zebra finch. A study of alarm calls in Australian magpies ('Gymnorhina tibicen'), a prolific songbird, is used here to give an example of possible considered responses in alarm calling based on behavioural evidence.