­­­Status and distribution of an introduced population of European Goldfinches (Carduelis carduelis) in the western Great Lakes region of North America

Abstract

Monitoring introduced species is important because of possible effects on native species and ecosystems. Here, we report on European Goldfinch observations from North America between 2001–2021, focusing on a population in the western Great Lakes region. We compiled over 7000 records of European Goldfinches from multiple sources for this time period. Over 3300 records were from the western Great Lakes region. We believe the primary founding event of this population to be release or escape from a cage bird importer in northern Illinois.  European Goldfinches were initially reported widely in the region, but over time birds were most consistently reported between Milwaukee, Wisconsin and Chicago, Illinois. They have been breeding in this area continuously since 2003, are currently present in numbers that have established them as part of the local avifauna, and show evidence of a recent increase in numbers.  More study is needed on this population of European Goldfinches, including their ecology, their potentially increasing range and population, and an evaluation of the potential for impacts on native ecosystems.