This morning, on my way to work in low light and in the rain and from across the lake, I was able to pick out a Cackling Goose mixed in with the large Canada Goose flock at Peace Valley. At first I thought it was a duck, then it turned and I could see that it was a tiny goose with Canada Goose like plumage. Head was more rounded and bill was also shorter looking than Canada Goose. Even though the size difference was considerable, it was important to double check that against the Canada Geese in the flock to be completely sure. If the bird had been all by itself, it might have been tricky to be completely sure just how small the bird actually was. (photo:roysephotos.com
Cackling Goose is a rare but regular bird here, a few show up almost each winter, so it isn't unheard of. While my views were good enough to substantiate this identification, as I drove away, I wondered if this view would have been good enough to convince others if it was of a rarer species. Just as size matters, in birding, rarity matters. The rarer the bird, the greater the number of details that are expected before others accept a sighting. For a regional rarity like this, that occurs regularly, I can just report the sighting with minimal details, and it will make it into the county bird records. If I had found a much rarer bird, I'd be expected to provide a complete written record of my observations. If the bird had never occurred in the state before, I might also be expected to provide a photograph, before the record could be completely accepted. Same goes if I reported a bird that hadn't been reliably reported in over sixty years and that some already consider to be extinct.