I think that one bird would be just as acceptable an entry in a "brids in action" category as a single landscape would be in last month's "landscapes" contest. IMO, the plural in the competition title represents the hope for a plurality of entries. I myself am hoping for a shot of a particular bird usually found singly, so if I'm successful there will only be multiple birds in my shot if there are incidentally others in the background of the image I post.

So please post your photo, be it of one or many birds! Photos of a feather flock together, I always say.