the range of the lesser Goldfinch (Spinus psaltria) has expanded northward through the northern rocky Mountain states of Wyoming, idaho, and Montana since at least the early 1990s (stephens et al. 1990, stephens and sturts 1998, Faulkner 2010, Montana Bird distribution committee 2012, Marks et al. 2016), although this went largely unrecognized on a range-wide scale until recently (e.g., Watt and Willoughby 2014). initial colonization of Montana probably occurred both east of the continental divide through Wyoming and west of the divide through idaho. However, movement across the divide within Montana is also a possibility, since lesser Goldfinches were not reported in Montana west of the divide until 2011 even
though they were present and breeding in southern idaho by 1988 (stephens et al. 1990, stephens and sturts 1998).