Avian Conservation and Ecology (Dec 2024)
An ecological perspective on the temporal variation in Pileated Woodpecker ( Dryocopus pileatus ) drumming behavior in Alberta, Canada
Abstract
As old-growth forest ecosystems become increasingly scarce in North America, the need to accurately and efficiently survey old-growth specialists and keystone species, such as the Pileated Woodpecker ( Dryocopus pileatus ), becomes increasingly important. A common survey method for birds is to detect auditory cues to determine presence. Therefore, it is important to understand temporal patterns in audible cues, which are often linked to a species’ breeding phenology, to optimize survey timing. It is well known that the Pileated Woodpecker, as a non-migratory bird, has a breeding season that begins before most migratory passerines arrive at their breeding grounds. However, the timing of the peak Pileated Woodpecker breeding season, and therefore auditory activity, is relatively unknown at the northern extent of its range. We explored the temporal variation of Pileated Woodpecker drumming behavior using passive acoustic monitoring methods at the northern extent of its range in Alberta, Canada. Peaks in auditory cues were near sunrise (06:00) in early April (2 April). Mean daily temperature and day length were the most influential environmental variables that affected the drumming of Pileated Woodpeckers. Drums were more likely to be detected at daily mean temperatures close to zero degrees Celsius and on days where day length was approximately 13 hours long. Based on these findings, we calculated that a minimum of ten one-min long surveys should be conducted during the peak periods of Pileated Woodpecker activity (near sunrise in early April) to ensure accurate presence/absence data for this species in Alberta, Canada. These guidelines can be used for planning future surveys and methods to utilize existing non-optimized surveys to ensure the accuracy of Pileated Woodpecker site occupancy.
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