Songbirds and Energy Development

Energy development has become a primary source of anthropogenic habitat alteration in the western US, with the majority of development occurring within sagebrush dominated landscapes.  Since May 2008 we have been examining questions relating to fitness consequences for sagebrush-obligate birds nesting in the Upper Green River Basin, WY. Field crews locate and monitor songbird nests across an existing energy gradient in the Jonah gas field and Pinedale Anticline Project Area (PAPA).  Our prior research has demonstrated decreased daily nest survival rates of the three sagebrush-obligate songbird species (Brewer’s sparrow, sagebrush sparrow and sage thrasher) with increased surrounding habitat loss due to natural gas development.  This decreased nest success was due to increased predation, with three quarters of observed nest depredation events attributed to rodents.  This research also identified a relationship between elevated songbird nest predation rates and rodent abundance in areas with increased habitat loss from energy development.

To better understand the cause of nest failures in this system, we must also examine mechanisms driving small mammal abundance. We are currently testing two alternative hypotheses to explain observed increases in small mammal abundance associated with energy development. Nest monitoring, small mammal trapping, and mesopredator surveys are being conducted across a gradient of habitat loss to asses whether predators for which rodents are a primary prey item may be less abundant near energy development.  We are also assaying body condition of captured small mammals to assess whether reclaimed areas near well pads, which are primarily composed of native and non-native grasses and forbs rather than sagebrush, are providing supplemental food to rodents.

Shrubland and grassland bird populations are declining faster than any other group of avian species in North America. With increasing demands for domestic sources of energy, the identification of specific mechanisms influencing nest predation is a critical next step in developing clear strategies for mitigating the impacts to songbirds breeding in energy fields.

Watch Nest Predation Clips!

Gallery

Nest searching sites are located across a gradient of energy development. Some sites have very high densities of energy development, as displayed in this aerial photo of the Jonah Field. Photo: J Sartore

This is a lower well-density nest searching plot on the Pinedale Anticline. Nearby natural gas wells can be seen in the distance in this photo.

A nest searching plot on the Pinedale Anticline. Plots are located across a gradient of adjacent energy development.

A male Brewer's sparrow singing from his sagebrush perch. Nests are located based on adult territoriality behaviors and systematic searching.

Male Brewer’s sparrow singing from a sagebrush perch.

A sagebrush sparrow nest with eggs. After nests are located, they are monitored every 2-3 days to assess nest success.

Sagebrush sparrow nest with eggs. After nests are located, they are monitored every 2-3 days to assess nest success

Nest monitoring continues until the nest fails (due to predation or abandonment) or until nestlings fledge from the nest. Shown here are Brewer's Sparrow nestlings approaching fledging age.

Infrared cameras are set up at a small number of songbird nests at each site to identify the suite of predators responsible for nest depredations. 75% of predators observed since 2011 have been rodents (primarily deer mice and chipmunks). Photo: A Stupik

Infrared cameras are set up at a small number of BRSP and SATH nests at each site to identify nest predators.

In 2014 we started small mammal trapping on grids adjacent to all nest searching plots to assess small mammal abundance relative to nest predation rates. We use both Sherman (shown here) and Tomahawk traps to capture both nocturnal and diurnal species

We have rodent trapping grids adjacent to all nest searching plots to asses small mammal abundance relative to nest predation rates

All captured small mammals are tagged with a unique identifier to allow for mark-recapture analysis, including this Least Chipmunk

Least chipmunk All captured small mammals are tagged with a unique identifier to allow for mark-recapture analysis

Field technicians also collect body size measurements and demographic information for all captured individuals. Photo: T. Scherr

Field technician Marie Martin and a recently PIT tagged deer mouse.

We are also interested in local abundance of rodent predators. Badgers are a primary predator for rodent species, such as the Wyoming ground squirrel in this photo. We're using remote trail cameras to assess badger and coyote activity at our study sites.

Badgers are a primary predator for rodent species, such as the Wyoming ground squirrel in this photo. We’re using remote trail cameras to assess badger and coyote activity near at our study sites.

Rodents are also important prey for raptors. We are conducting raptor point counts to asses raptor activity at our field sites.

Rodents are also important prey for raptors. We are conducting raptor point counts to asses raptor activity at our field sites.

We hope that this research will further reveal what mechanisms are driving nest survival and rodent abundance in areas with high concentrations of energy development in the sagebrush steppe.

On the eastern edge of the Jonah gas field at sunset.

Reports & Publications

Hethcoat, M.G. and A.D. Chalfoun. 2015. Towards a mechanistic understanding of human-induced rapid environmental change: a case study linking energy development, nest predation and predators. Journal of Applied Ecology.  View PDF

Hethcoat, M.G. and A.D. Chalfoun. 2015. Energy development and avian nest survival in Wyoming, USA; A test of a common disturbance index. Biological Conservation 184: 327-334. View PDF

Gilbert, M.M. and A.D. Chalfoun. 2011. Energy development affects populations of sagebrush songbirds in Wyoming. The Journal of Wildlife Management 75(4): 816-824. View PDF

Contact

Lindsey Sanders, M.S. candidate
WY Cooperative Fish & Wildlife Research Unit
Dept. 3166, 1000 E. University Avenue
Laramie, WY 82071
[email protected]
lab: (307) 766-2091
fax: (307) 766-5400

Anna Chalfoun, Ph.D. – Project PI
Assistant Unit Leader/Assistant Professor
WY Cooperative Fish & Wildlife Research Unit
Dept. 3166, 1000 E. University Avenue
Laramie, WY 82071
[email protected]
lab: (307) 766-6966
fax: (307) 766-5400

Project Lead

Lindsey Sanders

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Timeline

Summer 2008-2009: Two seasons of field research completed by Michele Gilbert and Anna Chalfoun. Field work consisted of nest searching and monitoring, avian point counts, and vegetation sampling.

Summer 2010-2011: Two seasons of field research completed by Matthew Hethcoat and Anna Chalfoun. Field work consisted of nest searching and monitoring, remote camera surveillance of nests to identify nest predators, visual predator surveys, vegetation sampling, and some small mammal trapping.

Summer 2014: Field research completed by Tracey Johnson and Anna Chalfoun. Similar field methods used as in 2010-2011.

Summer 2015-2016: Field research completed by Lindsey Sanders and Anna Chalfoun. Field work consisted of nest searching and monitoring, remote camera surveillance of nests to identify nest predators, vegetation sampling, robust small mammal capturing, scent stations to identify coyote and badger abundance, point counts to identify aerial predator abundance, giving-up density trays to assess perceived predation threat by rodents.

Funding & Partners

• Wyoming Landscape Conservation Initiative, USGS
• Wyoming Game & Fish Department
• Wyoming Wildlife: The Foundation