Today was one of those bread-and-butter days with enough birds to keep me occupied but sufficiently spread out to avoid any unwelcome stress. A few dark clouds on the horizon briefly raised anxiety levels mid-morning, especially as there was no mobile phone signal, meaning that the rainfall radar app. I normally rely on was out of action. This gives me an audible warning when precipitation is within 20k of the site, which is just about enough time to get all the nets furled before a shower arrives. In the event, I made a judgement call and carried on.
At the end of the session, I made my way across to Horswell Ditch. The leaking sluice was repaired earlier this year and it’s now holding the intended amount of water. Unfortunately, an invasive alien aquatic plant from southern Africa, Lagarosiphon major, known as curly-leaved waterweed, has established itself and spread uncontrollably, floating just below the surface. Whether this arrived naturally or was introduced by a well meaning but ill-informed member of the public is open to question but it’s here to stay.
However, every cloud has a silver lining. A bit of research revealed that it is an ideal soil improver and compost accelerator. The soil on my allotment in Plymouth is heavy clay and desperately needs organic matter to improve its quality. Other plot holders use seaweed in vast quantities but I am reluctant to collect this from the natural environment so the waterweed provides a sustainable alternative. Using a grapple on the end of a length of rope, I can drag an appropriate amount onto the bank, where I leave it for a couple of hours to drain and to allow any organisms to get back into the water before bagging it and driving it back to Plymouth. A win-win situation!
On a more positive botanical note, for the first time in over a decade Broadleaf Cattail typhus latifolia has appeared in places along the northern bank of the ditch. This species had gradually disappeared from the reserve as the water table fell, a consequence of excessive ditching operations in the past. However, the open water and unshaded banks of Horsewell Ditch seem to have provided long-dormant seeds with the right conditions to re-establish. A favoured winter food source for Reed Bunting and Bearded Tit it’s a welcome return and an indication that Horswell Ditch may be achieving its objective of raising the water table in one of the drier parts of the reserve.
Back to the ringing. 64 birds were trapped with just four re-traps amongst them. This included the first two Grasshopper Warblers and the first three Garden Warblers of the year. Totals were: 3 Blackbird, 4 Blackcap, 1 Bullfinch, 3 Cetti’s Warbler, 3 Chiffchaff, 3 Garden Warbler, 2 Grasshopper Warbler, 6 Reed Warbler, 3 Robin, 21 Sedge Warbler, 14 Willow Warbler and 1 Wren.