European birds in the Midwest -- paper published

[I've cross-posted this here as many people land on this page when searching for information on these birds] 

The paper on this research has been published!
It's open access so you can read online or download the PDF; click on title below -

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

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History and background on this project:

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 began working on a paper covering 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 collaborated on this part of the project. I'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 was compiling a database of sightings for the past 20 years or so and cull important information from this. This data is 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. Although all reports that have been submitted to eBird have been incorporated (including those not showing in the public maps and output), there is a substantial amount of data that, unfortunately, is lost to history. The eBird data is challenging to work with -- for example, many records 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). Therefore, the dataset required substantial cleaning and quality checks.

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A number of European Goldfinches (Carduelis carduelis) have been recorded in Dearborn, MI. The first was found on 11 January 2003 and last reported on 11 March 2003. Another was captured and banded 14 September 2010. This was followed by these additional sightings:

• 21 March and 5 April 2016, UMD campus. On the first date, I (JAC)  recorded a male singing near the parking structure; on the latter date it was reported elsewhere on campus coming to a feeder near the library.
• 25 July to 13 August 2017, coming to a west Dearborn feeder near Ford Field; photographed.
• 26 February 2018, UMD campus (reported by O. Gelderloos) 
• 3 April 2018, reported in the Golfview subdivision in west Dearborn (J. Turek).
• 11 May to 8 June 2018, coming to a feeding station at the Environmental Interpretive Center on the UM-Dearborn campus, seen by many.
• 6 July 2018, coming to the same west Dearborn feeder near Ford Field.

This is a popular cage bird species, and reports of escaped or released birds are not uncommon. A request on the RRBO web site in 2003 for other reports in the region revealed a large number of sightings in the western Great Lakes, with rumors that an importer had released his stock of European cage birds. RRBO’s research resulted in the 2008 paper (pdf) Current status of European Goldfinch (Carduelis carduelis) in the western Great Lakes region in the journal North American Birds. 

Other species: I'm still interested in records of any of the following European/Eurasian species (links are to photos to help with identification): Common Chaffinch (male and female), Eurasian Siskin (male and female; similar to our native Pine Siskins which are duller with thinner bills), European Greenfinch, Great Tit, Blue Tit, Linnet, Eurasian Jay (links are to photos to help with identification).

How to identify a European Goldfinch

European Goldfinch in the UK by Joe/freebird4 under a
Creative Commons license.

Adult European Goldfinches are distinctive and have the same plumage year-round. Males and females are nearly identical; scroll down for more information and photos of how to tell them apart. 

There are a number of different subspecies. In the eastern part of their native range, they look quite different. Here is a link to the
gray-headed form (these are also being reported in small numbers; I have no nesting records of this subspecies).

Young European Goldfinches lack the head markings of the adults. The photo above is a juvenile. See also these links.

• European Goldfinch — juvenile
• European Goldfinch – juvenile 2 (scroll down page to image 8601)
• Young American Goldfinch for comparison (note juvenile American Goldfinches are dijon-mustard colored, with broad beige wing bars and never have streaking nor jet-black wings like young European Goldfinches).
  

Common questions about European Goldfinches in North America

Where did these birds come from? Apparently, a large importer of birds in the Chicago area released a great many birds of a number of species around 2002.  There were reports of Eurasian birds from the area prior to that time, probably ones that escaped from the poorly-maintained quarantine station. Birds not in the Upper Midwest may be examples of other escapes and releases.

Where are these birds being reported? To date, I have received hundreds of reports of European Goldfinches, as well as lesser numbers of reports of other species.  Most are in northern Illinois and southern Wisconsin, radiating from the Chicago area where the releases reportedly occurred.  The pattern is primarily north from Chicago, and along the Lake Michigan shoreline, but reports are by no means restricted to these areas.  There are reports from all over Wisconsin, as well as from Iowa, Indiana, Ohio, Michigan, and Ontario (the areas from which I’ve requested reports).

Are they nesting? Yes. I have confirmed nesting reports of European Goldfinchs in Illinois, Wisconsin, Ohio, Ontario, New York, and California.

Are they harmful? The only species that appears to be present in significant numbers are European Goldfinch.  They do not appear to be a threat to any native species, but of course non-native species can behave in unexpected ways.  This is one reason we need to track the movement and expansion of these birds.

Will European Goldfinches hybridize with American Goldfinches? Probably not.  They are the same genus, but at least in Great Britain, European Goldfinches breed much earlier in the summer than American Goldfinches.

Can they survive the winter in the north? Yes. They are hardy birds. They eat a variety of weed seeds in the wild, and they will also come to bird feeders.

European Goldfinch in Dearborn, MI, fall 2010

This European Goldfinch (Carduelis carduelis) was captured and, with the permission of the U.S.G.S. Bird Banding Lab, banded, by the Rouge River Bird Observatory on 14 September 2010.

This species is not native to North America, and is a popular cage bird. Sightings across the eastern U.S. in particular are common, and this is the second we have had in Dearborn. The first, found on 11 January 2003, spawned this project documenting sightings in the western Great Lakes region. While this bird, like most in southeast Michigan, is most likely escaped or released from captivity (read on for evidence), European Goldfinches have become established as a breeding species in northern Illinois and southern Wisconsin, and perhaps elsewhere. This was apparently the result of repeated releases by an importer near Chicago. You can read more about this in a paper I published in 2008.

The bird was an adult, based on a fully-ossified skull. If the bird were a juvenile, the skull would not be completely ossified in this species until at least November.

It was a male, based on several plumage characteristics. First was the uniform deep black color of the wing feathers, including the wing coverts. In females, the coverts would be duller black, and/or have brown edges. The wing and tail feathers were all fresh, with no indication of cage-wear. European Goldfinches molt earlier in the season than American Goldfinches, and adults would be nearing completion of their fall (or prebasic) molt at this time. This bird was still molting many body feathers, but had nearly completed replacement of the wing feathers (only the last two secondaries, also known as tertials, were incoming).

A second characteristic was the black coloration of the feathers bordering the upper bill and nasal area, which in females is brownish. This last feature in particular is very well illustrated on this web site.

A final clue was the extent of the red mask, which in males covers the upper rear border of the eye. The head feathers were molting, with many feathers just coming in — these appear as the whitish “rice grains” interspersed in the feathers in the photo at right. Thus the full extent of the mask may be a bit broader than it appears at this time. This feature is compared side-by-side in this photograph, and also shows the different-colored nasal feathers of each sex.

Generally, males also have deep crimson-colored masks, and females have more orange-red masks. Red, orange, and yellow plumage coloration in birds is dietary in origin. Birds cannot manufacture these colors and must ingest certain carotenoid pigments in order to produce the “right” colors. A diet insufficient in proper carotenoids can result in what is normally red plumage being orange or yellow. The masks of European Goldfinches are comprised of four different carotenoid pigments.

Inexperienced cage bird owners (such as the ones who might intentionally release their birds or are careless enough to allow them to escape!) may feed their birds a monotonous, poor diet which could account for incoming feathers coming in yellow. Once on the loose, a European Goldfinch in this area finds a large variety of appropriate foods — favorite foods of this species in Europe and Asia include knapweeds (Centaurea spp.), burdocks (Arctium spp.), and teasel (Dipsacus spp.), all established non-native species here. This is a very hardy species, able to survive cold winters easily, and one which will visit bird feeders readily.

There are at least twelve recognized subspecies of European Goldfinch in Europe and Asia, which vary in coloration and size. I am not suggesting this bird is a wild vagrant, but do know that more than one subspecies are both wild caught and captive-bred and imported into the U.S. In addition, there are seven or more color forms bred by cage bird fanciers. Thus, the mask coloration may be not be an indication of poor diet (although I think it is the most likely explanation), but merely some variation on the nominate subspecies.

References 

I have several updates here on Net Results of photos and updates of nesting birds: Click here.

My paper:  Craves, J. A. 2008. Current status of European Goldfinch (Carduelis carduelis) in the western Great Lakes region. North American Birds 62:498-501.

Cramp, S., and C. M. Perrins. 1994. Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palearctic. Vol. 8. Crows to Finches. Oxford Univ, Press, Oxford, U.K.

Dinsmore, S. J.  and W. R. Silcock.  2004.  The Changing Seasons: Expansions. North American Birds 58:324-330. (excerpt below)

Jenni, L. and R. Winkler. 1994. Moult and Ageing of European Passerines. Academic Press, London and San Diego.

Lopez, G., J. Figuerola, and R. Soriguer. 2008. Carotenoid-based masks in the European Goldfinch Carduelis carduelis reflect different information in males and females. Ardea 96:233-242.

Excerpt from “The Changing Seasons” in North American Birds Spring Migration, March-May 2004: "Old World finches, reported in small numbers beginning late last fall, continued to figure in the regional reports: scattered reports of European Goldfinches stretching from Manitoba (one in late autumn) to northern Ontario (many) and to Quebec (two in winter), single Eurasian Siskins in Quebec, New Brunswick, and in Michigan, and a …Eurasian Linnet in Michigan?  Most record committees relegate records of “cage” birds to “status unknown” categories, and for good reason.  With help from Julie Craves and Alan Wormington, we opened a Pandora’s Box of surprises from the Great Lakes: reports of Eurasian Jays, Common Chaffinches, European Greenfinches, Saffron Finches, Eurasian Linnets, a Blue Tit, and two pairs of breeding Great Tits — plus hundreds of European Goldfinches coming to feeders across a nine-state, three-province area.  Most of these have not been reported in this journal.  A rumor has persisted that a large importer, International Zoological Imports in Vernon Hills, Illinois (near Chicago) closed its doors in 2002 and released many of its charges into the wild.  As Craves notes, “there is no confirmation of this rumor, but a compilation of reports does suggest the Chicago area as the point of radiation.”  Still, as John Idzikowski points out, records of European Goldfinch were on the rise around the Great Lakes before 2002 .[Some European bird records may be true vagrants] …Most of the finches, however, are either imported or propagated (legally) in the United States … . This is all very disheartening, especially when one considers the apparent distances traveled by some of these (assumed) escapees: European Goldfinches reached Gimli, Manitoba, Thunder Bay, Ontario, and White Sulphur Springs, West Virginia while a Common Chaffinch made it to Silver Islet (in Lake Superior), Ontario and the Eurasian Siskins traveled to Whitefish Point, Michigan, the Gaspe Peninsula of Quebec, and Lorneville, New Brunswick!  These are mostly fall and spring records, suggested that these presumed former captives still tend to move as migrants in season.  Sharp (2002) has asked already in this column about separating the wheat(ear) from the chaff(inch), but one has to keep the question alive: hypothetical flights of goldfinches from Chicago to Thunder Bay (740 km) or Whitefish Point (less than 600 km) or even the Lake Winnipeg area (~1200 km) are impressive, but the siskins in the Gaspe and the Saint John, New Brunswick areas were almost 1800 km away from the Windy City.  How far to the east in Canada do these birds go before they become inseparable from the Eurasian finches reported there occasionally as apparent legitimate strays? Some would argue that Nova Scotia and Newfoundland and Laborador hold the key: neither province has seen a flight of finches in this century that would provide context for any of the Great Lakes (or nearby) birds.  The only Eurasian birds of note this season in the Maritimes, aside from waterfowl, was a Eurasian Hobby — but editor Blake Maybank was quick to point out the ship-riding habits of small falcons, amply substantiated in the Sea Swallow, the annual report of the Royal Naval Bird Watching Society. Despite overwhelming circumstantial evidence that most of the Eurasian passerines notes around the Great Lakes were not of wild provenance, we still think it important for observers to record what they see and study individual birds in detail.  Caleb Putman, for instance, studied the Michigan siskin carefully, noting three retained juvenal outer greater coverts, indicating a bird in its first spring — probably the most likely age to make a navigational error on its first migration.  As there are known propagators of this species in North America, the proper ageing of this individual does not lay to rest concerns about its provenance.  However, we hope that other observers of such birds will go to similar lengths to identify and age birds of this, sort so that, minimally, we come to know what birds inhabit our landscapes and what their movements might be.”