Date: 12/19/17 9:29 pm From: Jim Mountjoy <jmountjo...> [ILbirds] <ILbirds-noreply...> Subject: IBET That goose in McLean County
On Sunday I received a phone call from a birder friend who asked "Are you looking at a Barnacle Goose?". My reply was "Why would I be looking at an escapee?". However, on Monday I was at a car dealership in East Peoria and my business did not take TOO long, so I figured that Towanda was not so far away...
I arrived at the borrow pit and had my scope on The Goose almost immediately, thanks to some direction from Ted Hartzler. It is a pretty bird. I also enjoyed the Snow Geese there (a county tick that I knew I could actually count), but was disappointed by the lack of Cackling Geese, although Ted's info on a couple of other spots to check eventually led me to that species as well. Later I tracked down the State Farm White-winged Scoter, so I definitely added a few county birds.
But about that goose. This is not my first Barnacle Goose, but the species is not yet on any of my official lists. I would like to be relatively confident that any bird I add to my list has a high probability of being a wild bird. What does 'high probability' mean exactly? I am not sure. The scientist in me says that it should be a 95% probability or greater, but I suspect my standards could slip a bit below that level, from a listing point of view. But would I be satisfied with 'a preponderance of the evidence' (say, a 60-40 probability that this particular bird is wild)? I don't think so. And the argument that 'you can't prove that the bird isn't wild' does not seem right to me.
I know that Barnacle Geese are not rare in the ornamental waterfowl trade (the prices are generally at or below $400 it seems, from a quick web search). And Illinois, in particular, is a long way from Greenland or even New England, where records are now routinely accepted. But I also know that it is quite plausible that a wild Barnacle Goose could show up here, so I do expect debate to ensue.
Today I opened my newly arrived copy of 'Ontario Birds' (Dec. 2017, Vol. 35 No. 3), and was surprised to see that the lead article was "The case for accepting Ontario reports of Barnacle Goose" by Mike V.A. Burrell. It lays out an argument for considering (many? some?) Ontario records of Barnacles as valid wild birds. He presents what I feel are some strong points (I didn't know that there have been seven Greenland banded Barnacle Geese recovered in NE North America) as well as acknowledging some points that might not support the 'wild' hypothesis so well. I would also add that Illinois is not Ontario, and the arguments may not hold up as well in the center of the continent. However, if you are pondering the provenance of Barnacle Geese in North America, I think that you should try to read this article if you can. (And yes, that certainly includes any IORC members who may be reading ;) ).