Anyone else have experience of finch flocks and trying to count numbers?
I finally got round to doing my first tetrad of the winter today (NJ40M) and the finch flock issue was a significant factor.
I had spoken to the landowner of a large part of this tetrad beforehand. As he was very enthusiastic about birds it made things a lot easier as I felt happier wandering across fields and into odd corners than I would have done otherwise.
I started off across a stubble field and soon put up seven skylarks and a couple of meadow pipits. A bit further on a flock of Linnets flew up from the ground. I photographed this flock and counted it later (94 birds). A pond at the bottom of the hill held 41 Mallards, 1 Moorhen and a single female goosander.
Things got more complicated as small numbers of yellowhammers started to fly up from the ground and into shrubs at the edge of the field. Closer inspection showed a mixture of yellowhammers, reed buntings, greenfinches and linnets in among the shrubs. The Linnets flew up into a tree in one group which made things easier, but only some of the other birds were visible at any one time and they were constantly on the move. I could only very roughly estimate about 15 Yellowhammers, 5 reed buntings and 3 greenfinches.
Shortly after I ran into a flock of chaffinches. Again they were constantly on the move in small groups between a row of trees and feeding on the adjacent field. I estimated 50 but it could have been more. There were bramblings amongst them - I saw 8 for sure but estimated 10.
I came across a suspiciously similar sized flock of chaffinches not far away 5-10 minutes later, feeding in a grass field. However, there were only one or two bramblings with them and about 10 goldfinches, so I gave them the benefit of the doubt as a different flock.
My route took me up onto the top of a low heathery hill which was devoid of birds apart from a couple of buzzards. Coming down the other side I passed through a small forestry plantation, with the obligatory small mixed flocks of coal tits and goldcrests high in the canopy (more guesswork on numbers!). At the bottom of the hill there were two bullfinches in a young plantation and two birds flew over calling loudly, landing in the trees behind - I'm fairly sure they were crossbills of some sort but the call wasn't a typical one.
Returning to farmland I encountered yet another flock of about fifty chaffinches - again moving through the trees around me and there could easily have been more. A few Yellowhammers and greenfinches were with them and then a small group of about 8 redpolls appeared. They were very flighty and I didn't get a good look at them. Their wingbars appeared fairly pale, but they had to go down as common/lesser.
The final challenge was a distant flock of 380 mixed rooks and jackdaws. Counted from photos but the split between the species was an educated guess.
The final count was 31 species in two hours.