Craves, J.A., and N.M. Anich. 2023. Status and distribution of an introduced population of European Goldfinches (Carduelis carduelis) in the western Great Lakes region of North America. Neobiota 81:129-155. doi: 10.3897/neobiota.81.97736
This paper is open access, so you can read it online or download the PDF by clicking the title above. (The figures look better in the PDF.)
The backstory is on this page.