Experimentally elevated corticosterone increases song output and complexity in common mynas

Area of Science:

• Animal Behavior
• Avian Ecology
• Neuroendocrinology

Background:

• Vocalization in birds serves as a crucial communication method, reflecting internal and external states.
• Bird vocalizations are known to change under stress, influenced by stressor type and environment.
• Glucocorticoids, like corticosterone, are stress hormones that can mediate physiological changes affecting vocal behavior.

Purpose of the Study:

• To investigate the effects of experimentally elevated corticosterone on adult bird vocalizations.
• To determine if corticosterone elevation impacts song and call output and complexity.
• To examine dosage-dependent and sex-specific effects of corticosterone on vocal communication.

Main Methods:

• Experimentally elevated corticosterone levels in adult common mynas (Acridotheres tristis) using a noninvasive method.
• Administered two different levels of corticosterone to assess dosage effects.
• Monitored and analyzed vocalizations (song and call output, song complexity) at various time points post-administration.

Main Results:

• Temporary increase in song output and complexity following corticosterone elevation.
• Decrease in call output observed after corticosterone administration.
• Effects were dose-dependent, with higher corticosterone levels showing stronger impacts.
• Vocal changes were most pronounced around 40 minutes post-ingestion and exhibited sex-specific patterns.

Conclusions:

• Acute corticosterone elevation significantly alters vocal output and complexity in common mynas.
• The observed vocal changes are influenced by hormone dosage and sex.
• Further research is needed to understand the behavioral and reproductive consequences of these stress-induced vocal modifications in birds.