Assessing monitoring techniques for bird populations in Sierra Nevada montane meadow and aspen communities

Graduation Date

2008

Document Type

Thesis

Program

Other

Program

Thesis (M.A.)--Humboldt State University, Biology, 2008

Committee Chair Name

Joseph M. Szewczak

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Habitat models, Point count, Audio recorder, Sierra Nevada, Humboldt State University -- Theses -- Biology

Abstract

Point count and species-specific surveys are widely used to infer avian abundance and species richness. However, advancements in bioacoustic technology enable automated survey alternatives that can expand the landscape coverage with equivalent personnel resources. We surveyed birds in the Sierra Nevada from May to August 2006 using both point count surveys and automated audio recorders. We developed an avian monitoring protocol by conducting point count surveys every 7 to 10 days for a total of eight times during the breeding season. Vocalizations of willow flycatcher (Empidonax traillii), Lincoln's sparrow (Melospiza lincolnii), and Wilson's warbler (Wilsonia pusilla) were broadcast at every point count station. Our results suggest that three point count surveys per field season, and point count durations of 10 min, optimize the number of species detected and sampling effort expended. Aural stimuli can supplement point counts as a quick and easy method to increase detections of the three hard to detect focal species. Habitat models were developed for the three hard to detect species plus dusky flycatcher (Empidonax oberholeri), song sparrow (Melospiza melodia), and yellow warbler (Dendroica petechia) using the habitat variables: meadow size, and percent cover of tree, riparian deciduous shrub, and herbaceous vegetation. We compared point count and automated recording unit surveys by placing audio recorders at point count stations and recording avian vocalizations. Point counts detected more species than audio recorders when sampling time was the same for both methods. However, audio recorders provided more hours of data than point count surveys, with the same amount of effort. The increased sampling intensity of audio recorders will likely result in additional species being detected and assisted in detecting a willow flycatcher in a meadow where none were detected during standard willow flycatcher surveys.

https://scholarworks.calstate.edu/concern/theses/g732dc482

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