Idaho SH-21 Wildlife Management Linkage Project

Project Description

More mule deer are killed by vehicles on a 22-mile stretch of roadway east of Boise than on any other stretch of road in southwest Idaho. This stretch includes 8 miles of Warm Springs Avenue, which runs along the base of the Boise Foothills and parallels the Boise River. It moves east through city neighborhoods and then suburban developments that are scattered across the valley. This checkerboard of houses and bare land gives way to open space along 14 miles of State Highway 21. Much of it is public land or part of the Idaho Fish and Game’s Boise River Wildlife Management Area (BRWMA...

Project Map

Publicly Accessible: Yes
County: Ada County, ID; Boise County, ID
Project Size:
  • 1.74 miles

Project Sites

  • Idaho State Highway 21, Boise Idaho
  • Wildlife Exclusion Fence
  • Wildlife Underpass

Goals and Targets

Primary Motivations:

  • Conservation Mission
    To conserve big game populations and habitat connectivity
  • Public Benefit
    To reduce the number of wildlife-vehicle collisions on SH-21 and Warm Springs Ave.

Consistent With Plans:

  • Habitat Conservation Plan
    This project is consistent with the Boise River Wildlife Management Area Habitat Plan

Targeted Habitats:

  • Shrublands and Grasslands
    • Shrublands and Steppe
      • Sagebrush Shrubland and Steppe

Targeted Species:

  • Elk Cervus canadensis
  • Mule Deer Odocoileus hemionus

Conservation Actions

Action Status Start Year End Year
Other - Species conservation and management: Reduce Wildlife-Vehicle Collisions In Progress 2010 2014
Construct wildlife crossings & fencing


Is the success of this project's actions being monitored? Yes

Monitoring Activities
We have wildlife cameras that take photographs of animals using the underpass.

Quick Facts

Owning Organization


Managing Organization

Boise River Wildlife Linkage Partnership

Contact Information

Edward Bottum (Wildlife Habitat Manager)
Idaho Department of Fish and Game

General Information

Project #: 99875
Last Updated: April 12, 2012

Project Relations


Ada County
Ada County Highway District
City of Boise
County of Boise
Idaho Department of Fish and Game
Idaho Transportation Department - R3
Mule Deer Foundation
Rocky Mountain Elk Foundation
U.S. Forest Service


Boise River Wildlife Linkage Partnership Website

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