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Assessing Feasibility of Mitigating Barn Owl - Vehicle Collision in Southern Idaho

Started: August, 2013 Ended: January, 2016 Project ID #4W4565 Status: Completed

Results & Findings

The final report summarizes research designed to understand the spatial, road geometric, and biotic (land cover and prey) factors associated with barn owl-vehicle collisions and examine feasibility of mitigation. It provides a literature review of barn owl road mortality and mitigation approaches from North America and Europe. The greatest rates of mortality along I-84 occurred between Bliss and Hazelton, Idaho. Mortality increased when the highway was close to the Snake River Canyon, close to dairies (agriculture), and farther from water features, and when there were fewer nearby roads, narrower medians, fewer human structures, and a higher percentage of cultivated crops. Owl road kills were higher when plant cover type in the median and right-of-way was grass rather than shrubs. The research team recommended that mortality hotspots be the focus of initial mitigation. Efforts to reduce barn owl mortality should focus on vegetation management in the right-of-way to promote tall shrubs or scrub vegetation to reduce “huntability” for owls, and keeping grassy areas to very low heights to potentially reduce abundance of small mammals through decreased food and cover for them. There should also be development of barriers (hedges or trees, nets, fences, berms or other) to restrict low flight by owls in mortality hotspots. Reducing wildlife-vehicle collisions involving barn owls is an important step in ensuring persistence of this avian species. In so doing, it would reduce chances that the conservation status of barn owls is elevated, which would bring heightened regulatory challenges to the transportation sector in Idaho.

Objective

The purpose of this project is to identify the areas of highest barn owl road mortality on a segment of Interstate 84; to determine the roadway, geographical and biological factors contributing to mortality; and to explore management/mitigation activities that may reduce such collisions.

Abstract

Barn owls are killed by vehicles in large numbers along major roads in southern Idaho. Interstate 84 represents the highest vehicle-caused mortality rate recorded for barn owls worldwide. Additionally, as collisions happen at night and at high speeds, owl-vehicle collisions put motorists in a dangerous and potentially costly position. WTI is teaming with researchers at Boise State University to identify the areas of highest barn owl road mortality along a segment of I-84; to determine the roadway, geographical and biological factors contributing to mortality; and to explore management/mitigation activities that may reduce such collisions.

Contacts

Files & Documents

Sponsors & Partners

  • Boise State University Sponsor

Part of: Road Ecology

Project Tagged In: wildlife-vehicle collisions

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