After several weeks, or even a couple of months, I've noticed that birds are starting to sing again. Green finch for the last two days (or maybe in their case it's just their call, but they have been silent since mid August). I've just been outside and a great tit was singing away. I know it's not the most beautiful song, but I just love it, makes me think of the early part of the year. I was surprised. I understand that robins start to sing at this time of year, because they're already starting to establish their territories for next year's breeding season, but great tits?