The effect of sunrise timing and mountain aspect on the dawn chorus of Swainson’s Thrush

Authors

  • Ramnik Aojula University of Alberta
  • Anna Jacobsen University of Alberta
  • Erin Bayne University of Alberta

DOI:

https://doi.org/10.29173/eureka28799

Keywords:

Swainson's Thrush, Catharus ustulatus, Mountain Aspect, Direction, Time Since Sunrise, Dawn Chorus

Abstract

This study centers on the Swainson’s Thrush (Catharus ustulatus), uniquely identified by a buffy eye ring, uniformly brown back and tail, and a distinctive flute-like song with an ascending pitch. With a prevalent presence in woodlots, parks, and fruiting trees, they breed in coniferous forests with dense undergrowth, displaying notable vocalization and behaviour patterns. This research aims to explore the impact of pre- and post-sunrise timing and mountain aspect (North, East, South, West) on the dawn chorus of Swainson’s Thrush. The hypothesis posits that those exposed to earlier sunlight will sing prior to those experiencing delayed sunlight. Specific predictions are made for each mountain aspect, considering temperature, sunlight exposure, and resulting bird activity levels. To test the hypothesis, five audio recording units (ARUs) are set up across the mountain's four sides. Three recordings are made before and after sunrise for each side, grouped as North, South, East, and West. Results reveal a statistically significant interaction between direction and time since sunrise, while direction alone does not significantly impact song frequency. Time since sunrise and Julian's days also influence singing behaviour. The study shows the intricate relationship between environmental factors, sunrise timing, and mountain aspect on the dawn chorus behaviour of Swainson's Thrushes. These findings underscore the need for further investigation into additional factors influencing the dawn chorus, contributing to avian ecology and conservation understanding. By unravelling these complexities, conservation efforts can be better informed and aligned.

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Published

2023-11-21

How to Cite

Aojula, R., Jacobsen, A., & Bayne, E. (2023). The effect of sunrise timing and mountain aspect on the dawn chorus of Swainson’s Thrush. Eureka, 8(2). https://doi.org/10.29173/eureka28799

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Articles