The sad decline of HGF?

HGF this morning was relatively quiet with the gulls having moved on and the fields devoid of life due to the farmer harrowing the fields. A Common Sandpiper was the only real interest. Having recently reviewd some records I found the following stats for the pool in August:
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Tufted Duck 30-40 (2006) 50-70 (2007) 50-70 (2008) 16-35 (2009)
Pochard 20-30 (2006) 7-9 (2007) 8-12 (2008) 0-6 (2009)
Little Grebe 15-22 (2006) 11-19 (2007) 10-23 (2008) 5-7 (2009)
Black-necked Grebe 1 (2006) 3-5 (2007) 4 (2008) 1-2 (2009)
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On the flip side:
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Coot 55-60 (2006) 25-57 (2007) 70-110 (2008) 75-89 (2009)
Great Crested Grebe 3-4 (2006) 5-8 (2007) 7-9 (2008) 12-16 (2009)
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The Tufted Duck numbers are concerning this year - the summer/early autumn moulting flock is well down on recent years and Pochard have virtually disappeared. The Little Grebe flock is also concerning - last year the autumn flock which normally numbers around 25 birds disappeared virtually overnight and this year numbers are well down. I can only think disturbance is to blame though other factors may be at work. This morning no Pochards and only 16 Tufted Ducks though a repeat visit this evening produced 25 of the latter. A pair of Kestrels were annoying a Buzzard which was hanging in the wind on the east side - something they like to do. I have seen four Buzzards in a line simply hanging in the wind on the east side before.
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A swift divert around Frodsham in extremely windy conditions produced 2 juvenile Black Terns over No. 6 tank along with at least 400 Sand Martins and a couple of Swifts. The dodgy hybrid Ruddy Shelduck with the very white face was also around. No waders were immediately visible, I went to the far end to scan from there and saw a long line of waders stretched out right across the middle of the mud flat. At the limit of my scope I counted approximately 310 Ringed Plover and 120 Dunlin though they all scarpered back towards the Weaver bend before I had the chance to scan for the Wood Sandpiper or the Curlew Sandpiper which has been around for a week or so.