nivalis are primarily northern species the southern extent of their geographic ranges occurs in the Rocky or Appalachian Mountains, respectively. erminea (ermine, stoat or short-tailed weasel), M. Three of these species were commonly trapped furbearers: M. Members of the genus Mustela (= Neogale ), hereafter referred to as weasels, were historically widespread and occurred in diverse terrestrial ecosystems across North America. To counteract this trend there is an urgent need to assess the status and trends of small carnivores. Compared to larger carnivores, they are equally endangered with extinction, yet their conservation status is less frequently evaluated. Globally, small carnivores are increasingly recognized as a group of species in need of conservation attention. By identifying population declines for small carnivores that were formerly abundant across North America, our findings echo recent calls to expand investigations into the conservation need of small carnivores globally. While none of these datasets are individually conclusive, they collectively support the hypothesis that weasel populations have declined in North America and highlight the need for improved methods for detecting and monitoring weasels. In 2019, systematic trail camera surveys at 1509 sites in 50 US states detected weasels at 14 sites, all of which were above 40 o latitude. frenata records since 2000 in portions of its central, Great Lakes, and southern distribution, despite extensive sampling effort. erminea, but a current range gap of >1000 km between two distinct populations of M. Comparisons of recent and historical museum and observational records suggest relatively consistent distributions for M. Nonetheless, after accounting for trapper effort and pelt price, we still detected a significant decline in weasel harvest for 15 of 22 evaluated states and provinces. Declining trapper numbers and shifts in trapping practices likely partially explain the decline in harvest. We observed 87–94% declines in weasel harvest across North America over the past 60 years. To investigate the status and trends of weasels across the United States (US) and Canada, we analyzed four separate datasets: historical harvests, museum collections, citizen scientist observations (iNaturalist), and a recent US-wide trail camera survey. erminea) are distributed across most of North America, yet several recent studies have reported difficulty detecting weasels within their historical range and several states have revised the status of weasels to that of species of conservation concern. Three weasel species ( Mustela nivalis, M. Small carnivores are of increasing conservation concern globally, including those formerly thought to be widespread and abundant.