# Shifting Syllable Production in an Ex Situ Population of a Critically Endangered Songbird

## TL;DR

A study found that a critically endangered songbird, the Bali myna, changed its singing patterns in response to human activity levels at a zoo.

## Contribution

This study is the first to examine how anthropogenic disturbance affects syllable production in an ex situ songbird population.

## Key findings

- Bali mynas produced more syllables per song when anthropogenic disturbance was higher.
- Syllable production showed plasticity across days and years.
- Only syllable number, not rate or diversity, responded significantly to disturbance.

## Abstract

Singing is an ecologically important behaviour for songbirds. Syllables function as the building blocks of birdsong, so changes to their production will have implications for overall song structure. It is well established that anthropogenic disturbance can influence syllable production in wild songbird populations, but the effect of anthropogenic disturbance on syllable production in ex situ populations has not been studied. We set out to fill this gap by comparing the syllable production of Chester Zoo's Bali myna (Leucopsar rothschildi) population during a period of zoo closure in 2020 (due to the COVID‐19 lockdown) to a period of normal zoo opening in 2019. The number of syllables per song, the rate at which syllables were produced and the diversity of syllables all showed evidence of plasticity across days and years. However, only the number of syllables per song responded significantly to anthropogenic disturbance. Changes in syllable number due to anthropogenic disturbance could mitigate potential signal masking from unpredictable noise, although communication efficacy may still be affected. As a result, changes in vocal communication could impact conservation breeding programmes by altering the way that individuals interact with conspecifics.

Bali mynas produced songs containing more syllables under increased anthropogenic disturbance.