Using autonomous recording units and change-point analysis to determine reproductive activity in an aerial insectivore

ABSTRACT

Autonomous Recording Units (ARUs) are commonly used, alongside traditional methods, to study the presence/absence of vocal species. ARUs are useful in monitoring species that are secretive or vocalise at night. We endeavoured to develop a method to monitor avian reproductive activity using ARUs. Olive-sided flycatchers (Contopus cooperi), an at-risk passerine, are an ideal species with which to develop this method as they have a loud distinct call and have large territories without much intrusion from conspecifics. Olive-sided flycatchers have a distinct call pattern during the breeding season. We used a change-point analysis to determine the dates of significant changes in their call pattern to determine if individuals were successfully breeding. We monitored 22 Olive-sided flycatchers in central New Brunswick in 2018 and 2019. We found that using a combination of ARUs and change-point analyses was a viable method for studying reproductive activity of Olive-sided flycatchers. We found that 27% of Olive-sided flycatchers were successfully breeding which, when considering erroneous classifications, is within the range of nest success (30–65%) documented elsewhere. Our method shows promise for studying other bird species as well as other vocal non-avian species.

KEYWORDS:

• New Brunswick
• Olive-sided flycatcher
• vocalisation
• monitoR
• call rate

Acknowledgements

We would like to thank NSERC Discovery Grant to JJN (grant # DG-306845) and Eastern Habitat Joint Venture for providing the funding for this study. We thank Nicole Murtagh and Sarah Cusack for their assistance in deploying and collecting Autonomous Recording Units and acoustic data. We thank Dr. Wendy Monk and Dr. Graham Forbes whose comments helped improve this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethical statement

This study was conducted with the permission of the University of New Brunswick’s Institutional Animal Care Committee.

Additional information

Funding

This work was supported by the Natural Sciences and Engineering Research Council of Canada [DG-306845]; Eastern Habitat Joint Venture.