Can birdsong save endangered species?

Introduction

My name is Rebecca and I am a 2nd year PhD student in the School of Earth and Environmental Sciences. I have been interested in animals and the natural world since I was very young, so chose to study Natural Sciences, specialising in Zoology, at undergraduate level. Following this, I was selected for an animal husbandry internship at Chester Zoo, which cemented my desire to work with animals in zoological collections. I focused on this in more detail whilst completing my MSc Wild Animal Biology, examining multiple aspects of conservation and animal husbandry.

My research focuses on how birdsong can influence conservation. Birdsong exhibits clear population differences known as dialects, which are similar to accents in humans. These dialects can form very rapidly, especially in small, ex situ populations. They also play an important role in mate choice, with females preferring local over foreign dialects. Conservation interventions often bring birds from different populations together, so dialect differences could impact mate choice. This could cause many problems, the most serious being that birds may not integrate and breed in their new population. 

Automated recording unit

In depth

Many songbirds are threatened with extinction. Unfortunately, critically endangered species are often hard to access and have low sample sizes, meaning this kind of research is not possible. To avoid this, I work with a model species, the Java Sparrow (Lonchura oryzivora), which is numerous in zoos and aviculture but threatened in its home range. Once studied in the model, we can expand our techniques to more critically endangered birds.

Recording birds

Recording birds can be surprisingly challenging! Environments are full of noise, whether natural (like water and wind) or man-made (like traffic or electrical appliances), which also show up on our recordings. Lots of different equipment is available for different situations. Recordings in controlled conditions can make use of sensitive directional microphones. However, recordings outdoors require sturdy automatic recording units (ARUs), which can be left for long periods in all weather.

Analysing songs

Although we may be able to hear differences between the songs of different birds, it can be difficult to understand and explain how songs are different through listening alone.  We can visualise songs as a spectrogram, which allows us to analyse songs much more accurately.

Generally, we are interested in two main parts of song: spectrotemporal and structural features.

Spectrotemporal features include information about the timing of the song, for example its duration and the intervals between notes, and spectral details, such as minimum and maximum frequency.

Structural features relate to the notes themselves - their shape, how they are grouped together.

Once we have extracted these features for songs from multiple birds, we can compare them to see how similar their songs are.  If bird songs are more similar within than between populations, it is good evidence that dialects exist in the species.

Going further

Find out more about songbird conservation with Chester Zoo’s Sing for Songbirds (https://www.actforwildlife.org.uk/what-we-fight-for/conservation-challenges/our-campaigns/sing-for-songbirds) and EAZA’s Silent Forest (https://www.silentforest.eu) campaigns

The Macaulay Library (https://www.macaulaylibrary.org) is a great birdsong resource with recordings from thousands of species.

My links

Chester Zoo profile link:

https://www.chesterzoo.org/conservation-and-science/work-with-us/conservation-scholars/rebecca-lewis

DTP Profile:

https://www.liverpool.ac.uk/studentships-earth-atmosphere-ocean/our-students/2017-2018/rebeccalewis/

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