Dave Dawson’s natural history notes for 21st March 2018:-

Black-headed gulls have assumed their breeding plumage, with dark heads and are disputing amongst themselves in preparation for departure for the breeding grounds. The Common gulls seem to have gone already. Canada geese are departing to breed elsewhere. A patrol man with a border collie dog on the golf course may now report success in deterring the birds, but what moves them isn’t the dog, but the desire to breed. There were no Cormorants, but let’s not jump to conclusions; this is the month when most of them depart to breed. Cormorant numbers recently have been close to the long-term average, so let’s not assume they have gone because of the lack of fish (or conversely that they have caused the lack). The 22 Mute swans show a decline back towards the numbers that occurred before the great increase in Autumn 2014. The other waterweed feeder, the Coot, is also nearly back to normal numbers. I fear that we may lose the abundant waterweed and return to a murky diatom-dominated lake. The recent wet weather has revealed places where ponding can occur in the park. This was seen around the north-eastern corner of the stadium enclosure and in the eastern corner of the park beside the mounding near the small children’s play area. Snowdrop flowering is over. In full flower were Blackthorns in the hedgerows and Sweet violets on the southern edge of the wood and Lesser celandine in the Glade. The leaves of Lords-and-Ladies, Cow parsley and Bluebells are well-developed and the flowers will come soon. Elders and Elm suckers are also leafing up. There is a small patch of Lily-of-the-Valley in the eastern corner of the park below the trees there. This is uncommon as a native species in London and hadn’t been spotted until this year. It’s very likely to be a garden throwout. Resident birds were singing. Mistle thrushes were singing in the woodlands and on the golf course. Stock doves were singing in both woods and also in the poplars near where the brook leaves the park. Great-spotted woodpeckers were drumming in both woods. Starlings were singing at the stadium and in Horse Close Wood. These last three species depend upon holes in old trees for their nest sites, showing the importance of old trees as habitat. Blackbirds were singing, and still feeding on the few remaining Ivy berries. Ivy flowers and fruits only where it can climb above the ground, again showing the importance of climbing Ivy as habitat. There was a report of a dead swan floating in the lake about a week ago. Four juvenile Black swans were seen on the lake on the 13th. It’s an offence to release this species into the wild in the UK. Their origin remains unknown, but they moved after a day. We would not want to be the place where they first breed successfully in the wild.