Thursday 21 May 2020

15th May 2020

I was out at 05:00 for my monthly standard bird count. For most of the time I was on my own, the first runner being seen at 07:50.
As for last Spring, one or two Black-headed gulls remained after the big numbers returned to breeding sites as far away as Russia. Although in breeding plumage, there was no sign of attempted nesting but this remains possible, with the nearest breeding site not far away at the Wetland Centre. Canada goose numbers are always low in May, but nine birds is less than usual. Perhaps there has been some control by the golf club? Numbers of Egyptian geese remain high and there was a lot of disputes going on and flying to and from their nests in trees, including one in the public park section of Ashen Grove Wood, benefitting there from the covid-19 closure of the childrens' play space. Coots were sitting on their nests, including one on the concrete canoe pontoon in full public view. There was another record count of Coots, 52 being 7 more than the previous May high from 2014. So Coots remain in unprecedentedly high numbers now that the waterweed has recovered in the lake. In contrast, Mute swan numbers have declined to three adults, compensated by a remarkable recently-hatched brood of eight cygnets, one more than the maximum cited in the reference sources. So our resident pair are competent individuals. Cormorants and Common gulls have departed to breed elsewhere.
Blackbirds and Song thrushes have nestlings to feed and are in trouble with the dry Spring, as this drives the invertebrates down in the soil beyond reach. So they become conspicuous as they venture into the open, risking predators whilst searching for food. Nevertheless, there was some song from both species. As usual there was at least one pair of Blackcaps in Horse Close Wood. There was no song from Blue and Great tits which were too busy finding food for their nestlings. A pair of Ring-necked parakeets had a nest in an old woodpecker hole in the veteran Oak by the picnic area.
I always see Grey squirrels in the park, but other mammals are more elusive. This morning there was a rare sighting of a large dog-fox trotting confidently out in the great field inspecting rubbish dispersed from the litter bins by squirrels and crows, or thrown down yesterday. He was competing with Crows and two Herring gulls for this. Again, the dry Spring and virus lockdown has probably limited his other sources of food. Foxes eat many earthworms when the soil is damp enough for them to surface and these will have been unavailable.
The Yellow-flag iris around the lake was beginning to flower. Bluebells were over, but Dog roses were in flower in the hedgerows and areas of tree planting. Watercress in the brook was in flower and Green alkanet, Jack-by-the-hedge and elder were flowering in the hedgerows. The lack of mowing has revealed six species not spotted before because they were not able to flower: the earliest of the buttercups to appear, Bulbous buttercup was seen in both children's play areas and the stadium, Ramsons was spotted in the crazy golf area and the early-flowering grass, Meadow fox-tail, was seen in several places. Several new patches of Germander speedwell were seen. I found a new arrival in the London area growing at the base of a Red oak in the crazy golf area, Early meadow-grass.  This insignificant little grass is spreading and this is my first record of it anywhere in SW London. Since then these wild flowers have all been decapitated by the mower.
Wood pigeons were feeding on Knotgrass and other annual weeds where the big top and Pines and needles had destroyed grass on the great field. A birch tree standing in the golf course near the Wimbledon Park Road entrance has died.
I did my lake water sampling two days later. As usual there was plenty of blanket weed and there were the same two waterweeds as last year: Fennel-leaved pondweed and Rigid hornwort. Water clarity was good because three species of water flea were keeping the diatoms down. A blue-green bacterium, celebrated as Aphanizomenon flos-aquae floated abundantly in the open water. The other things that were thriving were fish fry, non-biting midge pupae, little water boatmen, water lice, shrimps, snails, water mites, the swimming caddis larva, fish leeches and flatworms. These species show that the water quality is good and they provide food for the fish and for bats and birds that come to feed on emerging insects.

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