Looking forward to counting the Magpies into the island in Platt Fields lake this winter. This is easy though from a good vantage point. You count them in and subtract the ones that fly out.
I always used to wonder how counts added up to such odd figures - like the 189 Swift quoted. It's almost certainly the sum of several groups - the larger flocks being estimated and the smaller flocks being precise. For example, 3 groups of about 60 + 1 group of 9 = 189. If you can count 40ish and that's about a quarter of the birds, then you have a flock of 160ish...
A very good tip is to count a flock of birds in flight (or a flock of grounded geese, for example) from the back towards the front. Try it - it does work
How do you count large flocks of Birds. Take a recent post for example,1030 Swallow,189 Swift. I can estimate up to 40ish but past that, its just a big flock
