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Field Methods
CWMP uses trained volunteers to carry out snow tracking transects for wildlife adjacent to the
Interstate. Set transects are monitored on average three times over the course of the winter.
Transects were established at locations where crossing structures either existed and are being
improved or have been targeted for installation. Transects parallel the highway, about 150
meters from the road bed and field times document tracks and signs of any mammal species
larger than a snowshoe hare found along the route. At least one set of tracks is trailed on each
transect on each visit in an attempt to document the animal's relationship to the interstate.
Observations are photo-documented in the field and a sample of them are reviewed by expert
observers out of the field to assess observer reliability. All species of high conservation value are
photo-documented to ensure the accuracy of field documentation.
RESULTS AND DISCUSSION
Transect Data
As in previous years, coyotes where the most commonly detected species on transects. This
winter deer and elk represented 29% of all detections and one of these two species was recorded
at every transect besides Hyak/Silver Fir. The limited snowpack likely contributed to more
activity from these two species in the study area than is normal in winters with a more typical
snowpack. Deer, to some degree, and Elk, in particular, make large tracks and often make prints
even in very poor snow conditions. This makes definitive identification relatively easier than
other species in our study area. This fact could also have contributed to the increased
percentage of observations of ungulates compared to other species this winter.
By the middle of February all of our transects where either completely devoid of snow or with
only patches of snow remaining and all remaining transects were cancelled for the season. The
poor snow conditions and lack of snow on parts of transects that where completed contributed
to a larger than average number of observations made of sign other than tracks this winter (such
as scats, and feeding and marking sign on trees and other vegetation).
A single new species was documented this winter. Aplodontia, or mountain beaver, (Aplodontia
rufa) inhabit wet forests in the Pacific Northwest. In Washington State they are found most
commonly west of the Cascades Crest and in moist subalpine forests along the crest and in a
few locations east of the Cascades in similar wet subalpine habitat. They are active throughout
the winter but in areas with heavy snowfall, activity is primarily subnivean. The Hyak/Silver Fir
and SnoPass transects both have habitat commonly used by aplodontia. The extremely low
snowpack at SnoPass this winter likely contributed to the detection of this species as there was
no subnivean space for animals to use.
