Trying to count flocks of birds in flight is a difficult skill to master. It is a weakness of mine that, if I see a flock, I need to count them. From early September, it is the evening roost flight of Rooks and Jackdaws which commands the attention. In the last half hour before sunset the Rooks head for Oxnead, or to be more specific the woods and coverts that follow the Bure at that place. From a mere 500 in August, now in September the gathering appears to exceed 1000 individuals.
The slowly winding flock is best seen arriving over their roost with a strong breeze blowing. A force 4 is ideal. The last few minutes are spent riding the up draughts. The Jackdaws are the most nimble, but it is clear that the Rooks are not averse to some minor acrobatics. All this accompanied by a cacophony of what passes for song on the crow family. One of those sounds which are as familiar as traffic, but worth looking up for.