THE EVOLUTION OF VOCAL LEARNING
Humans learn language from others around them - but only a few other animals group learn their vocalisations in a similar manner, and songbirds are the best studied group. We use songbirds as models for understanding how humans acquire speech and language. But we have a very poor understanding of when and why this amazing ability evolved - we can't even define it very well. We're tackling this problem with a number of old and new tools, and some very old species. Read MORE about VOCAL LEARNING
Most animals communicate with innate sounds, but a select group of animals can learn new sounds. This special group includes humans, bats, elephants, some marine mammals (whales and dolphins), and three types of birds (parrots, songbirds, and hummingbirds). Birds are excellent models for human language research due to their accessibility and obvious behaviours. Future progress in this field requires a clear understanding of the evolutionary origins of vocal learning. However, recent research has drastically reordered the bird family tree. The new family tree has challenged many past assumptions, and lead to a hotly contested debate about when and how vocal learning evolved. The New Zealand wrens (Acanthisitti) are a critical missing link in this debate due to their unique position in the new bird family tree. However, very little is known about the vocal abilities of this group, and no one has tested them for vocal learning. Here, we are using behavioural analyses combined with quantitative genetics and new acoustic tools to determine whether this group of special New Zealand birds, are vocal learners. By studying the tītipounamu or rifleman, we aim to resolve the crucial question of when and how vocal learning evolved in birds. They are also New Zealand's tiniest bird, and super cute. HORMONES AS INTEGRATORS AND INDICATORS
Steroid hormones - like testosterone and corticosterone, are pretty powerful littel chemicals that can do all sorts of amazing things. They act as the go between, helping animals adjust to changing environments and circumstances. They can also regulate gene expression - coordinating changes throughout the body, integrating phenotypes so that the animal suits the world it inhabits. We use hormones to address lots of questions about how animals respond to challenges and how they can alter their behaviour and morphology. We are also investigating how hormones can help us with conservation goals. READ MORE ABOUT Hormones
A big part of understanding aggression, ornaments, weapons and songs in females is understand what factors influence these traits. For a long time biologist thought females have these traits simply because they are good in males. I've been exploring this possibility by looking at how a female's genetics, physiology and ecology interact to shape how she looks and acts.
For animals like birds and mammals (including humans) the steroid hormones are a major player affecting how individuals look and act. In particular, testosterone is important for regulating sex-differences and individual differences in traits expression. Testosterone is also influential in how animal their energy, whether they invest more in being a good parent, living a long time, or fighting with others. We know a lot about these relationships in males, but although we often here testosterone referred to as the "male hormone", females produce testosterone too. Unfortunately, we don't know much about what testosterone does in females. I've been working on this problem in Juncos, and have a new project soon to start in Crimson finches. So far I've learned that
The genes that make a good male may be different from the genes that make a good female. I'm using a long-term data-set to build a pedigree for Gouldian finches. I'll use this to investigate the importance of genes and early stress in shaping colour and size. I'm also looking at how these traits change with age in both sexes. I've just started on this project so stayed tuned for what we learn. SOCIAL SELECTION & COMPETITIVE TRAITS
Bright colours and deadly weapons make sense if you are a male trying to score in the sexual selection battle. But what if you are a female, or a young animal? Why would you waste energy producing such silly traits? Turns out, there is more to life (and reproductive success) than just sex. REad more about Social Selection
For animals like birds and mammals (including humans) the steroid hormones are a major player affecting how individuals look and act. In particular, testosterone is important for regulating sex-differences and individual differences in traits expression. Testosterone is also influential in how animal their energy, whether they invest more in being a good parent, living a long time, or fighting with others.Bright colors, lethal weaponry, bizarre ornaments, complex songs, intense aggression. These sorts of traits are gaudy and costly, and seem to scream, “Here I am, come eat me”. Consequently, they have been a source of fascination for biologist for decades. But after decades of research, we have a good understanding for why they exist. Females are limited in the number of eggs they can produce, while males are limited by the number of eggs they can access. This can exert strong pressure on males to out compete one another for access to females. Any and all traits that improve competitive ability (i.e. competitive traits) are favoured, to the point they are more costly than helpful. But we don't see these traits just in males. There are many species with females (and young animals) that have weapons, fight, display bizarre ornaments, and sing complex songs. This is puzzling for biologists, females are supposed to be limited by egg production and offspring care, and ornaments and competitive behaviours traits take energy away from those things. So why are they so common? We're still working on this problem - but it looks like the answer is that these sorts of traits are advantageous anytime you need to compete for a limited resources - mates, nest-sites, food from parents, etc. Even more interesting, it looks like the costs are also different - bright colours are not always more vulnerable to predators, and aggressive females are not always bad moms. |
Some popular press on our research
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SLEEP AND COMMUNICATION
Sleep is one of the few truly ubiquitous animal behaviours. We know from our own experience that sleep disruptions and poor quality sleep can have negative consequences for our ability to think and perform - does the same happen to birds and other vocal communicators? Does it impede learning, performance, both?
Sleep is one of the few truly ubiquitous animal behaviours. We know from our own experience that sleep disruptions and poor quality sleep can have negative consequences for our ability to think and perform - does the same happen to birds and other vocal communicators? Does it impede learning, performance, both?
rema more about sleep and communication
though many animals spend enormous periods of time asleep, we have only begun to understand the consequences of sleep disturbances. In humans, sleep is crucial for effective communication. Birds are classic models for understanding the evolution and mechanisms of human language and speech. Bird vocalizations are remarkably diverse, critical, fitness-related behaviours, and the way sleep affects vocalizations is likely similarly varied. However, research on the effects of sleep disturbances on avian vocalizations is shockingly scarce. Consequently, there is a critical gap in our understanding of the extent to which sleep disturbances disrupt communication. Here, we argue that sleep disturbances are likely to affect all birds' vocal performance by interfering with motivation, memory consolidation and vocal maintenance. Further, we suggest that quality sleep is likely essential when learning new vocalizations and that sleep disturbances will have especially strong effects on learned vocalizations. Finally, we advocate for future research to address gaps in our understanding of how sleep influences vocal learning and performance in birds.
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