Canda Thistle, Bull Thistle and Musk Thistle are non-native species to North America and are often considered invasive. (BTW Canada Thistle is native to Europe, not Canada). All of these have naturalized to some degree in North America, and all three are in Illinois.
The European Goldfinch is native to, you guessed it, Europe, but a breeding population has taken hold in parts of Illinois. Having established a population in the wild, they’ve been moved from being a provisional species in Illinois to a naturalized exotic species .
So, the finches’ favorite thistles from back home have become a nuisance to be managed, but it seems to be working out for the birds.
“On January 9, 2024, the Illinois Ornithological Records Committee (IORC) voted to add European Goldfinch to the state checklist. The American Birding Association Checklist Committee uses a rubric of a 15-year breeding period as one requirement before considering an exotic to be established, and a paper by Craves and Anich (2023), concludes that breeding has occurred continuously since 2003. Hence, any European Goldfinch identified from 2018 to the present is eligible for a birder’s Illinois Life List, along with other life lists such as County or Site lists. Year lists from 2018 to 2022 will not be updated by the LCC. However, the LCC has decided that it can be counted for 2023 year lists, and, of course, going forward.”