New distribution data of the least weasel Mustela nivalis in Castilla y León, Spain

The least weasel (Mustela nivalis Linnaeus, 1766) is the world’s smallest carnivore (King & Powell 2007) and probably one of the most difficult to detect (García & Mateos 2009). It is widely distributed throughout the northern hemisphere (McDonald et al. 2016), and seems to be a common and relatively abundant species, at least in some areas of the continent (Larivière & Jennins 2009, Tikhonov et al. 2010). However, many basic aspects of its biology, distribution, population dynamics and ecology remain largely unknown in most areas of its range, a lack of information that is especially striking in Spain (Palazón 2017).