There was just a little rain in the last few days of August, but appreciable rain waited until 22mm fell over four days, 8th to 11th of September. This was still too little to charge up the ground water, but sufficient for grass to resume growth and the lake to rise to within 24mm of the crest of the outfall weir, allowing wave action to cause a little overtopping. So, the watersports finally had regained the 140mm lost to evaporation and seepage over the long, hot drought.
The bird count was done on the 10th, before the effects of the rain on the grass had been seen and there were some remarkably low counts. There were no Canada Geese, Mallards or Black-headed Gulls on the lake, just two gulls and 2 geese on the athletics grass. The trend for the Canada Goose continued their low counts in July and August, but the second lowest September gull count over the last 40 years could well have been an immediate response to the return of significant rain making food available in other London sites. Only one year in the last 40 had no Mallards. There were just 22 Woodpigeons detected, fewer than seen in recent Septembers. In contrast, other species were as numerous as normal for September, with 20 Cormorants and 50 Greylags. The 10 House Sparrows were the highest September count since before the great decline in the London area in the 1990s and the 150 Starlings the highest since September 1989. The sparrow feeds its nestlings on insects and the Starling probes in grassland for invertebrates, so neither would have been expected to do well in a drought year. Some of this could be a taste of years to come. As seen often in the past there were extra Mute Swans being chased off by the resident pair, in this case there were just two interlopers.
Early in the month, a strange notice appeared posted on the security fence between the public park and AELTCs part of Ashen Grove Wood. This tiny bit of ancient woodland is no more hazardous than is Horse Close Wood, which is wholly accessible to the public.
I did my monthly lake water monitoring on the 14th. This confirmed that the cyanobacterium that dominated from early August, Microcystis aeruginosa, was still abundant across all three of my sampling points, if not blooming, and water clarity remained low. So, the ulrasonic device installed by Merton was not having a noticeable effect. The other main plankton was two species of water flea.
