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CEC-PIER: Funded Projects

Evaluating diverter effectiveness in reducing avian collision with distribution lines at San Luis National Wildlife Refuge Complex

Contract #: 500-01-032

Contractor: University of California, Santa Cruz

Subcontractor: Ventana Wildlife Society

Contractor Project Manager: Brian Walton

Subcontract Project Managers: Karen Ritchie Shihadeh

Commission Project Manager: Linda Spiegel

Commission Contract Manager: Linda Spiegel

The Issue

California’s Central Valley contains approximately 6320 miles of transmission line, 952 of which are located in National Wildlife Refuges or state wildlife areas. At 174 million birds annually, collision-induced avian mortality estimates in the U.S. are considered conservative due to our lack of information on both extent of and collisions associated with smaller distribution lines. Marking studies on larger voltage transmission lines have demonstrated reduced incidence of avian collision. Power companies, in an effort to reduce avian fatalities and satisfy federal mandate are interested in exploring and developing cost effective, practical, and functional bird diverter technology.

Anticipated Benefits for California

This study will give power companies and refuge managers more choices when selecting diverters for specific environmental variables, thereby enabling them to make decisions that are both effective and economical.

Project Description

San Luis National Wildlife Refuge Complex (SLNWRC) provides an ideal setting to study avian-energy system collision risk because it is speciose, contains high risk habitat, large tracts of wetlands with dense winter fog; it has approximately 40 miles of low lying 12 kV distribution line and it has a documented history of collision induced mortality and line outage. SLNWRC located in California’s Pacific Flyway includes San Luis, Merced, San Joaquin River NWR and the Grasslands Wildlife Management Area. It is an important migration stopover and wintering site for cranes, waterfowl, geese, shorebirds, raptors and passerines. Each winter it can host up to 20,000 California-threatened Greater Sandhill Crane (Grus canadensis tabida), over 850,000 ducks, and at least 70,000 geese including Aleutian Canada, Ross’, Snow, and White-fronted geese. Moreover, the major avian guilds represented there including cranes, ducks, geese, and swan are considered high risk for power line collision due to low wing loading, morphology, and flight and flocking behavior.

Ventana Wildlife Society with in-kind support from Pacific Gas and Electric Company and US Fish and Wildlife Services’ San Luis National Wildlife Refuge Complex will assess flight behavior from several avian guilds in response to two types of bird flight diverters at San Luis National Wildlife Refuge Complex during periods of peak avian over wintering use and Central Valley fog. The project began in November 2005 and will continue through March 2007.

Final Report

Available December 2007.

Contact

Karen Ritchie Shihadeh
Ventana Wildlife Society
10945 Portola Dr., Ste. F1
Salinas, CA 93908
(831) 455-9514