JEA 2018, 2(1), 7; doi: 10.22261/jea.qvdzo7
Seasonal changes in acoustic detection of forest birds
1 Nipissing University, 100 College Drive, North Bay, Ontario P1B 8L7, Canada
2 Algoma University, 1520 Queen St E, Sault Ste Marie, Ontario P6A 2G4, Canada
* Author to whom correspondence should be addressed.
Received: 30 Sep 2017 / Accepted: 1 Mar 2018 / Published: 11 Apr 2018
Autonomous recording is commonly used to examine the structure of avian communities in a variety of landscapes. Many birds return to the breeding grounds in May yet acoustic surveys typically begin in June. In many species, singing activity declines through the breeding season and so detections may be lower later in the season. The aim of our study was to compare the species richness and the community composition measured early (mid-late May) and later (mid-late June) in the breeding season. We recorded the community of singing birds at 13 locations in York Region, Ontario, Canada woodlots over two days using autonomous recorders. We used spectrographic analysis to scan recordings and identify all vocalizing species. We found that species richness was significantly higher in early recordings compared to later recordings with detections of both migrants and residents displaying this trend. Most food and foraging guilds were also detected significantly less often later in the season. Despite changes in species richness, the proportion of the community represented by each foraging guild did not vary between early and late recordings. Our results suggest that acoustic recordings could be collected earlier in the breeding season, extending the survey period into May. If the primary goal of monitoring is to document species presence/absence then earlier recordings may be advantageous.
Keywords: field recording; autonomous recording; bird community; Emerald ash-borer; canopy defoliation
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Ehnes, M.; Dech, J.P.; Foote, J.R. Seasonal changes in acoustic detection of forest birds. JEA 2018, 2, 7.
Ehnes M, Dech JP, Foote JR. Seasonal changes in acoustic detection of forest birds. Journal of Ecoacoustics. 2018; 2(1):7.
Ehnes, Mandy; Dech, Jeffrey P.; Foote, Jennifer R. 2018. "Seasonal changes in acoustic detection of forest birds." JEA 2, no. 1: 7.