These are the seeds, or keys, of the Manitoba maple that feed so many birds and squirrels all winter. I was checking out how many are left around the FWG, and I'd say more than 75% of the Manitoba maple keys have been consumed. By winter's end, there will only be some here and there remaining. This maple is native to the Prairie provinces (hence its name), but is considered an invasive in Ontario. However, it seeds prolifically and grows quickly (not always a plus in many people's minds) and therefore quickly produces seeds which feed wildlife.