Bird News: Ibsley Water– water pipit 1. Ivy Lake – Cetti’s warbler 1, water rail 2. Woodland – brambling 1
I saw the best bird of the day within a couple of minutes of arriving on the reserve this morning. From the Tern hide a group of pipits on the shore included a moulting water pipit, presumably the one that was seen with a rock pipit last week. I even got a passable picture of it.
At the Ivy North hide the view was like one of those habitat scenes with a range of species all on view at once. The Cetti’s warbler was singing away, the pair of water rail were picking about at the base of the bank, a heron was fishing, the mute swan was on her nest, although when she stood I could not see an egg. There was also a pair of shoveler just below the hide with a shelduck.
Otherwise the only other bird of note that I heard of was a single male brambling. Other finches were almost completely absent with just a couple of lesser redpoll and siskin.
As it was Thursday the volunteers were in and we were working on the western shore of Ibsley Water clearing willows and repairing fences ready for the arrival of the ponies next month. The sunshine brought out quite a few butterflies, but most of them went unidentified as they flew past as we were working. There was quite a brisk onshore wind and I noticed it had blown in a swarm of Daphnia water fleas, there were tens of thousands of them and they were as big as I have ever seen.
These zooplankton species are a very important element in the lake ecosystem,. They eat algae, the phytoplankton, and in turn feed a whole host of larger predatory species. But it is their role in controlling the algae that is critical, if they cannot keep up with the algal growth the population can get so large that it dominates the lake and stops the light penetrating deep into the water where the higher water plants, the macrophytes, can utilise it. The water plants are what feed the birds like coot and gadwall and provide the cover for much of the insect life. So it is vital the algae are kept in check and it is the zooplankton that does this job, which these Daphnia just about the most important habitat managers on the reserve.