Vocal and Social Learning of Avian Calls

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Human language is one of the most impressive outcomes of evolution. We are one of just a few mammals (whales, elephants, seals, and bats, but no other primates) that learn their vocalizations. In contrast, vocal learning is common in birds, with thousands of species requiring social input for learning. Bird songs have become an exceptionally important model system for addressing all aspects of biology, ranging from gene expression and neural function to ecological and evolutionary questions. Just like humans produce different words and languages, many bird species also have diverse vocalizations for communicating a wide variety of information about their environments. However, to date only one of these signals (the sexual signals, or 'songs') has been studied in relation to vocal learning. The proposed work will be the first to examine vocal learning in other types of bird vocalizations ('calls'). I will examine vocal learning of two of the most important types of vocalizations that birds use to communicate about their environments: mobbing calls, and social group calls. The proposed study will focus on two groups of birds, each of which possesses highly developed social and ecological systems: tits (Family Paridae) and parrots (Family Psittacidae). Tits are some of our most beloved back-yard birds in the UK and although many of their behaviours are well studied, we know surprisingly little about their mobbing alarm calls. These calls advertise predators and recruit other flock members to harass, or 'mob' them. First, I will examine the mobbing calls of each species of British tit (great, blue, coal, marsh, willow, and crested tits) with field experiments to look at phylogenetic patterns in mobbing calls and whether they use a similar signalling system to North American chickadees. Chickadees have one of the most sophisticated alarm call systems of any animal, with different calls indicating the type of predator and subtle variations within a call indicating the specific level of threat. Do British tits use a similar vocal system to communicate about predators in their environment? Next, I will examine how birds learn to produce their mobbing alarm calls using a series of laboratory experiments conducted at St Andrews. Last, I will study how birds learn to use the alarm calls of other species to gain information about predators through a series of social learning experiments. The ability of animals to eavesdrop on the vocal signals of other species is one of the most exciting areas of research in bioacoustics and this will be the first study to experimentally examine how they learn this behaviour.Like tits, parrots have complex social systems. Because they often live in fission-fusion societies with ever changing flock composition, they use social calls to communicate with flock members. Recent observations suggest that spectacled parrotlets may go one step further: they use specific vocalizations when engaging with certain individuals. Are these directed calls akin to human names? I will conduct experiments with a colony of spectacled parrotlets at St Andrews and make careful behavioural observations with wild birds in Panama to test how birds use their social calls to communicate with other members of their flock. If these birds use a system similar to humans, it will be the first demonstration of 'names' in an avian species, and will provide the basis for truly comparative work (with humans and dolphins) examining the ecological conditions required for the evolution of 'names.'This combination of work with tits and parrotlets will be some of the first research conducted on social and vocal learning of bird calls, will provide key advances in our understanding of how animals communicate about their environments with members of their own and other species, will lead to important research publications, and will enable me to establish my UK career and develop my reputation as a leading bioacoustics researcher.