Mechanistic Understanding of Energy Development Effects on Songbirds

In the WLCI region, the quality and condition of sagebrush steppe is a concern given the extent of rangewide land-use change, habitat conversion, and rapid energy development in sagebrush systems. Three migratory songbird species are considered near-obligates of sagebrush shrublands: Brewer’s and sagebrush sparrows and sage thrasher, all of which are designated Species of Great Conservation Need in Wyoming (Wyoming Game and Fish Department, 2010) and nest in Green River Basin. In collaboration with the WGFD, we initiated this multiphase project to address the WLCI management need to identify the condition and distribution of sagebrush songbird habitats and key drivers of change in those habitats.

In Phase I (2008 to 2009) of this project, we documented diminishing nest survival of all three songbird species along an increasing gradient of natural gas well density in the Jonah and Pinedale Anticline Project Area. In Phase II (2011 to 2012), we evaluated songbird nest survival in relation to natural gas well density and the activity of important nest predators by installing 24-hour infrared video cameras at nests and conducting surveys of the main predators across the same energy development gradient. We recorded nine species depredating eggs and nestlings, and 75 percent of all depredations were made by rodents. During our surveys, chipmunk detections decreased with gas well density, whereas mouse and ground squirrel detections increased. Nest survival of Brewer’s and sagebrush sparrows decreased with increased predator activity. 

Collectively, our results suggest that natural gas development alters the local activity and (or) abundance of key rodent nest predators, thereby increasing risk of songbird nest predation. During FY2014, we continued monitoring nests, identifying predator species, and assessing predator abundance at the same study sites across the same energy development gradient to ascertain the spatial and temporal consistency of our previous results. Data analyses are underway, and we have initiated Phase III to ascertain why the activity and (or) abundance of key rodent nest predators increase along a gradient of increasing gas well density. Understanding specific mechanisms behind effects of energy development on sagebrush songbirds will lead to more explicit management and mitigation recommendations for effectively maintaining songbird populations in the WLCI area and beyond, while also broadening our understanding of the Green River Basin ecosystem.

Wyoming Game and Fish Department, 2010, Wyoming State wildlife action plan: Cheyenne, Wyo., Wyoming Game and Fish Department, unpaged.

Products Completed in FY2014

• Hethcoat, M.G., and Chalfoun, A.D., 2015, Energy development and avian nest survival in Wyoming, USA -- A test of a common disturbance index: Biological Conservation, v. 184, p. 327-334, doi:10.1016/j.biocon.2015.02.009.
• Hethcoat, M.G., and Chalfoun, A.D., Toward a mechanistic understanding of human-induced rapid environmental change -- A case study linking energy development, avian nest predation, and nest predators: Journal of Applied Ecology (in review).

• Hethcoat, M.G., and Chalfoun, A.D., Toward a mechanistic understanding of human-induced rapid environmental change -- A case study linking energy development, avian nest predation, and nest predators: Conservation Biology (in review). 
• Hethcoat, M.G., and Chalfoun, A.D., What are indices indexing? A test using avian nest survival and energy development: Ecological Applications (in review). 
• Hethcoat, M.G., Chalfoun, A.D., 2013, Nest predation and energy development: What’s coming down the pipe for sagebrush-obligate songbirds?, presented at Joint meeting of the American Ornithologists' Union and Cooper Ornithological Society, Chicago, Ill., August 13-17 2013, (won Best Student Presentation Award), paper 33 at http://www.fieldmuseum.org/sites/default/files/2013AB_37.pdf. 

• Hethcoat, M.G., and Chalfoun, A.D., 2012, Increased nest predation and energy development -- What’s coming down the pipe for sagebrush obligates?, presented at the annual meeting of The Wyoming Chapter Wildlife Society, November, 2012, Laramie, Wyo.
• Hethcoat, M.G., and Chalfoun, A.D., 2012, Increased nest predation and energy development -- What’s coming down the pipe for sagebrush obligates?, poster presented at the 2012 annual meeting of The Wildlife Society, October 2012, , Portland, Oreg.
• Hethcoat, M.G., and Chalfoun, A.D., 2012, Increased nest predation and energy development -- What’s coming down the pipe for sagebrush obligate songbirds?, poster presented at the 2012 North American Ornithological Conference, August 2012, Vancouver, BC, Canada.
• Chalfoun, A.D., Hethcoat, M.G., and Gilbert, M.M., 2012, Songbirds and energy development: Patterns and mechanisms, presented at the 202 Wyoming Landscape Conservation Initiative science workshop, May 15-17, 2012, Rock Springs, Wyo. Workshop report available at https://www.sciencebase.gov/catalog/item/54610ad6e4b0ba83040c59f0.

• Hethcoat, M.G., and Chalfoun, A.D., 2011, Increased nest predation and energy development -- Understanding the mechanisms: Annual Meeting of The Wyoming Chapter Wildlife Society, December 2011, Jackson, Wyo. [presentation].
• Hethcoat, M.G., and Chalfoun, A.D., 2011, Mechanisms underlying increased songbird nest predation in natural gas fields: Annual Meeting of The Wildlife Society, December 5-10, 2001, Kona, Hawaii [poster].
• Hethcoat, M.G., and Chalfoun, A.D., 2011, Energy development and nest predation -- A proposal: University of Wyoming Zoology Department Brown Bag Seminar Series, April 2011, Laramie, Wyo. [presentation].
• Gilbert, M.M., and Chalfoun, A.D., (in revision), Increased nest predation and food limitation as potential mechanisms underlying sagebrush-obligate songbird declines within energy development fields: Condor (in revision).

• GIS maps of study area and locations of point counts and nests.
• Dataset consisting of avian abundance, diversity, nest success, nestling quality, habitat, and information on distance from and extent of disturbance.
• Gilbert, M., 2010, Influence of energy development on sagebrush-obligate songbirds, in Joint Ornithological Conference, February, 2010, San Diego, Calif. [presentation]
• Gilbert, M., 2010, Demographic responses of sagebrush-obligate songbirds to energy development in western Wyoming, in The Wildlife Society Annual Meeting, October, 2010, Snowbird, Utah. [presentation]
• Gilbert, M., 2010, Demographic responses of sagebrush-obligate songbirds to oil and natural gas development in western Wyoming: Laramie, Wyo., University of Wyoming, M.Sc. thesis, 72 p. Online at http://www.wyocoopunit.org/index.php/archives/2010/gilbert-m-m-demographic-responses-of-sagebrush-obligate-songbird/
• Gilbert, M., and Chalfoun, A.D., 2011, Energy development affects populations of sagebrush songbirds in Wyoming: Journal of Wildlife Management, v. 74, no. 4., p. 816-824.
• Gilbert, M., and Chalfoun, A.D., Nest predation and food limitation as potential drivers of sagebrush songbird declines within energy development fields (in preparation).

• GIS maps of study area and locations of point counts and nests.
• Dataset consisting of avian abundance, diversity, nest success, nestling quality, habitat, and information on distance from and extent of disturbance.
• Oral presentation, “Influence of energy development on sagebrush-obligate songbirds in Southwest Wyoming,” by M.Sc. candidate, M. Gilbert, at the Wyoming Wildlife Society meeting in Sheridan, Wyo. (November, 2009); awarded best student presentation.

• GIS maps of study area and locations of point counts and nests.
• Dataset consisting of avian abundance, diversity, nest success, nestling quality, habitat, and distance from and extent of disturbance information.
• Oral presentation at the Wyoming Wildlife Society meeting, Sheridan, Wyoming (November 20, 2008, by Michelle Gilbert).