I-90 Wildlife Watch: A Year in Review

I-90 Wildlife Watch: A Year in Review

Conservation Northwest / Aug 09, 2018 / I-90 Wildlife, Wildlife Crossings, Wildlife Monitoring

Since relaunching the program in 2017, wildlife sightings from motorists have informed crossing projects and understanding of wildlife around Snoqualmie Pass.


Through I-90 Wildlife Watch, motorists’ reports of wildlife sightings from North Bend to Easton have become a vital part of monitoring to inform wildlife crossings and other conservation work around Washington’s Snoqualmie Pass. This data from drivers builds upon other monitoring and research efforts in the Central Cascades to paint a picture of wildlife activity along I-90. Over the past year (June 2017-June 2018), motorists have reported more than 60 sightings of live and dead wildlife in the 30-mile project area.

Elk walking by a remote camera on Easton Island. Photo: Citizen Wildlife Monitoring Project / CNW

I-90 Wildlife Watch is a project of Conservation Northwest with support from Central Washington University, the Washington State Department of Transportation (WSDOT), the Washington Department of Fish and Wildlife, the U.S. Fish and Wildlife Service, and the U.S. Forest Service. Data from motorists of wildlife along the interstate, dead or alive, informs WSDOT’s I-90 Snoqualmie Pass East Project, Conservation Northwest’s I-90 Wildlife Corridor Campaign, and other efforts.

Whether the species are small or large, alone or in a group, dead or alive, each of these sightings has been reported to WSDOT and other state, federal and non-profit partners working in this area, aiding in our shared understanding of wildlife presence and use in important habitat adjacent to I-90.

“The reports we collect through I-90 Wildlife Watch build upon the tremendous data that trained volunteers gather through our Citizen Wildlife Monitoring Program, and we are proud to lead two programs demonstrating the value of citizen science.” said Jen Watkins of Conservation Northwest. “All of this information on wildlife presence in the Snoqualmie Pass landscape helps to not only inform WSDOT’s design and monitoring of I-90 wildlife crossings, but also informs our work and that of land managers to restore and manage the habitat immediately north and south of the highway to accommodate the movement of wildlife near these structures.”

A cougar near Easton Island. This cougar has a tracking collar as part of a wildlife study by the Muckleshoot Indian Tribe. Photo: Citizen Wildlife Monitoring Project / CNW

Due to their large size and populations in the Cascades as well as their propensity for traveling in herds, it is not surprising that elk and deer have comprised the majority of motorist sightings over the past year. In multiple locations, drivers reported groups of elk, often with their calves in the spring months. However, sightings were not limited to just elk and deer; there were reports of bear, cougar, and bobcat sightings this year as well.

In addition to examining the raw, statistical data of wildlife reports, biologists also evaluate the stories behind motorists’ sightings. In one report, a driver recalls flashing her brights and honking her horn at a single cow elk as it attempted to cross the interstate; the driver’s actions ultimately caused the cow to turn away from the traffic. Another report claims that a “cougar ran across the lanes of I-90 going eastbound to the area on the side of the road.” The motorist says: “It caught my attention as several cars were putting on their brake lights to slow down when the cougar ran across the lanes of traffic.” These anecdotes help paint a fuller picture of how animals interact with the highway during their day-to-day movements and seasonal migrations.

“I-90 Wildlife Watch data helps us not only assess wildlife species occurrence and distribution in the landscape,” says WSDOT biologist Josh Zylstra. “The data will also contribute to future performance assessments of the wildlife crossing structures we are building, and, together with the other data sets we get, the reports help to tell the story of how wildlife near the project area are interacting with the highway.”

Although reports to I-90 Wildlife Watch of live animals moving on or near by the highway are helpful, reports of dead wildlife can also provide valuable information since they contribute to biologists understanding of the rates and locations of wildlife-vehicle collisions occurring on I-90. In the past year, just about one third of motorist reports were of deceased animals. Zylstra says that WSDOT will be comparing “the locations and rates of wildlife-vehicle collisions in the project area before and after [the] construction [of crossing structures]” in order to assess the success of the structures in the future; a reduction in the collision rates will indicate that the crossing structures are effective.

A mule deer fawn at the same camera site at Easton Island. This is a busy travel corridor for multiple species! Photo: Citizen Wildlife Monitoring Project / CNW

Throughout the 30-mile I-90 Wildlife Watch project area, frequent reports from motorists of wildlife on or near the highway occur along a stretch of I-90 that spans from milepost 67 to 70 where the east and west bound lanes of the interstate split around a forested island just west of Easton. The high level of wildlife reports here complements the attention that this section of highway is receiving for improvements to increase safe passage in the next phase of the I-90 Snoqualmie Pass East Project, which include a series of wildlife overpasses, culverts, and bridges that will be constructed starting in 2021. Construction on the first wildlife overcrossing in the project area is expected to be complete in October 2018.

While the construction of the 15-mile I-90 Snoqualmie Pass East Project will continue through 2029, the information provided by motorists (as well as other research) today is informing both the project design and monitoring while increasing all of our understanding of wildlife living and moving through the Snoqualmie Pass region.

You can help by reporting the live and dead wildlife that you see on I-90 between North Bend and Easton at www.i90wildlifewatch.org/report-a-sighting