It's an identification band just like a leg band, don't know where it's from but you may try the Fish and Wildlife Branch for more specific info.
The large neck bands make it possible to view and ID flocks and keep track of birds by using binoculars (normally they get leg bands returned when a bird leg band is recovered). I've shot Gadwal in the Pitt Polder Marsh that had a blue band across the bill and leg band as well. Same thing, just a visual aid to observe the birds at a distance.
Back in the late 1970's I shot a goose on the Pitt River that had a yellow neck collar (T-55). It was released in the Pitt Polder as part of the goose project started by the Pitt Waterfowl Society. My dad (Bill Otway) and his buddy Richard Trethewey worked hard to get the lower mainland goose project going in about 1972. They brought in about 500 geese to the fraser valley from the prairies and I can remember dad and I going up to Enderby to collect goose eggs and catch goslings that were brought down here to start the base group of geese introduced to this area.
There were goose pens all over the valley from Stanley Park, the Serpentine Fen, Minnekada Ranch, Widgeon Creek, Maple Ridge, and up in the Harrison and Chilliwak areas as well (I can't remember all the areas, I was only about 14 then....). The birds were wing clipped and hope was they would stay the first year and when their new plumage grew back, they would migrate from here in the winter and return in the spring to nest. Unfortunately for the general public, the winters started to get milder then and the geese never did migrate and with the decline in hunting pressure and areas open to hunting, the geese have prospered into the current numbers and become a nuisance to parks, golfers and beaches everywhere around here. I guess most of us hunters look at it as just a large, successful project!
Dano
I guess I kind of sidetracked your post with the history lesson, hope that's ok.
One last note, my hunting buddy shot a duck in Burns Bog a few years ago that had a wire exiting from it's back. It was a tracking transmitter!