Date of Award:
Master of Science (MS)
David K. Dahlgren
Eric T. Thacker
Terry A. Messmer
To better manage dusky grouse (Dendragapus obscurus) and ruffed grouse (Bonasa umbellus), hereafter forest grouse, managers require better information on forest grouse population status and habitat selection. To address this need, from 2015-2017, I conducted research on a sympatric populations inhabiting the Bear River Range of northern Utah to develop a breeding survey protocol, assess habitat selection, evaluate dusky grouse response to livestock grazing, and determine hunter harvest rates.
The breeding census protocol that I developed compared listening intervals with and without electronic playback calls at designated survey stop locations. Using digital mapping software, I plotted the estimated location of male forest grouse based on where I heard males calling. I then evaluated grouse detections by using the date of detection, how many minutes post-sunrise calls were heard, and if grouse responded to electronic playback calls. I used the data to identify and classify habitat selection of each grouse. Walking breeding surveys were an effective tool for monitoring forest grouse population trends. Information from analyses will help provide a baseline for evaluating forest grouse breeding habitat in the Intermountain West and developing monitoring sites in other areas.
I intended to assess habitat selection for brood-rearing dusky grouse and the relationship between dusky grouse and seasonal livestock grazing. I found dusky grouse broods preferred to be near the forest edges or near mountain shrubs, whereas livestock were in areas that were more open. My results suggest that dusky grouse brooding activities can be compatible with livestock grazing where foliage and trees create multiple layers of forest canopy. My findings highlighted the need for continued research to assess livestock grazing impacts on dusky grouse.
I used wing-collection barrels to estimate population trends and hunter harvest based on data from collected wings regarding species, age, and sex. I also captured and leg banded forest grouse prior to the hunting seasons. Wing collection data proved useful in estimating population dynamics. Low leg band returns suggested hunter harvest was limited within my study area. This level of harvest likely had minimal impacts on the forest grouse populations in the Bear River Range.
Farnsworth, Skyler Y., "Forest Grouse Ecology and Management in the Bear River Range Northern Utah" (2020). All Graduate Theses and Dissertations. 7788.
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