Resident breeding Canada geese are marked nationwide with white neck collars. This helps biologists evaluate numerous aspects of the resident goose populations. It may have been marked as part of a study of local movements, survival, or where geese are coming from that are causing problems. Make sure that you call it in to the Bird Banding Lab or report it by internet. They'll send you a report on the specifics of it banding date and location.
Michael, white collars are put on other geese besides "wuskys". The marking of wuskys is to keep them from being counted on the dusky quota and therefore shutting down the goose season. Duskys were never intentionally bred to westerns as an attempt to maintain duskys. A few Duskys were held in a pen at Willapa NWR as cripples and they were released during a storm that wiped out the fence. They lived and have survived and bred with the local western Canada goose in Willapa Bay and the lower Columbia. As managers we have debated for years on what to do about them and how to keep them from being counted as duskys. The collars should help hunters know that they can harvest them at no risk to having their cards punched. I know several hunters who are on a mission to harvest as many wuskies as possible. More power to them and I hope they can shoot every last one of them.