DISTINGUISHING TRACKS OF MARTEN AND FISHER AT TRACK-PLATE STATIONS

Managing and conserving uncommon mammals, such as fisher (Martes penna nti) and American marten (M. americana), depend upon a reliable mechan ism to index their populations. In parts of their ranges where these s pecies are not commercially harvested, baited track stations provide a n alternative means to collect data on distribution and abundance. Alt hough tracks of many species can be identified using unique qualitativ e traits, distinguishing tracks of these closely related, similar-size d mustelids requires a quantitative approach. We present a general met hod to collect mensurative data from track impressions on carbon-soote d track plates and use this approach to distinguish tracks of fisher a nd American marten. We used 80 tracks from 21 individuals to develop a discriminant function that distinguishes tracks of adults of each spe cies. The linear combination of 3 variables, all associated with the p alm (interdigital) pad, correctly classified 95 (100%) test tracks. Th is result makes it possible to positively identify both species withou t using more expensive photographic bait stations and will facilitate development of regional survey and monitoring approaches for marten an d fisher.