Saturday, December 11, 2021

European Goldfinches: 20 year data summary underway

European Goldfinches have now been nesting in northern Illinois and southern Wisconsin for over 15 years. With the completion of the latest Wisconsin Breeding Bird Atlas, it's time to summarize the distribution and breeding information on this species.  

As of December 2021, I am working on a paper that will briefly cover the history of this species in North America with more detail of the status over the past 20 years; where this species is currently found and where it has nested recently; a focus on the origins, spread, and distribution in the Great Lakes states; breeding phenology and ecology in this region; and as much as can be gleaned about the ecology and potential impacts of the establishment of European Goldfinches in North America.
Nick Anich, coordinator of the Wisconsin Breeding Bird Atlas, and I are collaborating on this part of the project. We've met with several other researchers who are interested in looking at population genetics and morphology of European Goldfinches across the continent.

Around 2001-2004, a number of other European bird species were reported from the western Great Lakes area (scroll down on this page for details). Of those, Great Tit (Parus major) is still nesting in Wisconsin. I believe a couple of other species may still be present and reproducing, but they are much more difficult to quickly identify and a status update on them will have to be a future project, although I still collect records.

The initial task with the goldfinch project is just to attempt to compile a database of sightings for the past 20 years or so and cull important information from this. This data is coming from multiple sources, including hundreds of sightings provided directly to me from people responding to posts on these pages and the former Rouge River Bird Observatory web site. I'm indebted to these people, because they provide the backbone of early sightings that were never reported elsewhere. 

The majority of more recent records come from eBird, but because European Goldfinches are non-native and therefore not "countable" on birders' lists, they have not been adequately reported. This has been further compounded by differential treatment of non-native species in each state. We are working with all reports that have been submitted to eBird (including those not showing in the public maps and output), but believe there is a substantial amount of data that, unfortunately, is lost to history. The eBird data we do have is challenging to work with -- for example, of the 6300+ eBird records we have, many are duplicates of the same bird, sometimes the same day or multiple days at one location (which may be recorded in different ways by different observers).

I am no longer actively collecting data. However, if you have any sightings in North America from 1999-2021 that have not been entered into eBird, please do so. Even if they do not appear in the public output, we will see them when we access the eBird database, or they will be available to future researchers. If you have further questions or information, or information on other European bird species (list below) you can contact me via the form near the bottom of the right sidebar --> 

You can read a great deal of background on the European Birds in the Midwest page. I've included this post at the beginning of that page as many people land there first, so scroll down a bit for the earlier information.

Other posts on Net Results about European Goldfinches:

European Goldfinch: Established in the U.S.? -- Jan 2009
European Goldfinch update -- nesting in Illinois, Jun 2009
More European Goldfinches -- nesting in Wisconsin, Jul 2009
Update on European Goldfinches -- Apr 2012

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