One of those things

On the way to drop the kids off this morning I had my first Wood Pigeons of the year - a pair in courtship. There have been a growing numbers of reports in the last week so it was no surprise to see them but it is a real mystery to me how birds of this size just turn up. As far as I know they only migrate in daylight yet they seem to turn up early morning without me having seen any birds flying over. Later in the spring it is possible to see large flocks migrating north over Oslo but these birds that turn up early in Oslo seem to just appear and get straight down to setting up a territory and finding a mate.