Roger used the statistics gathered by these recorders to illustrate the impact of conservation over tinne 

 both on general numbers and specific species. As an example, he explained the methods of recording 

 butterflies and the objectives thereof. ^ 



Where rides were not managed, butterflies decreased. On the Bombsite grazed area numbers did not 

 show an increase and this led to re-thinking the ways and time of grazing. As for species, the greatest 

 increase has been in numbers of silver-washed fritillary which breeds in broad-leaved woodland, 

 especially oak woodland or woods with sunny rides and glades. Ten species of butterfly have stabilised 

 and nine have decreased. 



Dragonfly and damselfly numbers have been fairly stable with 2012 being a good year while the adder 

 population, similar to national trends, has decreased - perhaps due to fragmentation of isolated 

 communities. Dormice have been found in the woods and boxes are checked fortnightly from April 

 through September. Bird boxes thus far have been used by both Blue and Great Tits. 



All the work in Bowdown has showed how important people are to conservation work and Roger 

 concluded by answering his own question with a resounding yes - it is all worthwhile. 



20 November - The Jubilee River, its creation and wildlife 



Brian Clews 



Brian began his talk with information on the reasons for and construction of the Jubilee River. 



Flooding had occurred from the Cherwell Valley, through Cookham and Maidenhead to a severe extent 

 in the past and with increased building on the floodplains of the Thames, floods were affecting yet more 

 people and properties. Plans were made for a hydraulic channel, trapezoidal in shape, to run essentially 

 parallel to the Thames with an expected flow on a typical day to be 10m^/sec (commonly called 

 cumecs) and a maximum flow of 215 cumecs during flood control periods, about one-third the flow of 

 the Thames. There was an increased budget for target conservation areas, including reedbed and 

 wetland with some open scrapes; wildflower grassland with natural trees and shrubs; bird boxes, fish 

 passes and otter holts - all over about 193 hectares. As the money gradually ran out, less land was 

 available for this work and for the upkeep of the areas. 



The resultant project was opened by the Duke of York in 2002 but flood control was soon found to be 

 inadequate. During the storm of 2003 the Thames reached its capacity in 30 minutes but after opening 

 the floodgates the Jubilee River itself increased from 10 cumecs to 144 cumecs in 15 minutes, only 60% 

 of its expected flow, but even this flow caused severe damage to the weirs and bank. In the aftermath 

 the trapezoidal design of the river was found to be slightly inaccurate. A programme of repair and 

 upgrading, costing about £3.5 million, was undertaken, partly covered by funds from an out of court 

 settlement with the chief designers of the project. 



Brian concluded his talk by telling us that the Jubilee River project has been successful in providing a 

 range of habitats for wildlife. Plans for the habitat, which hopefully will be given a designation as a Local 

 Nature Reserve, included a number of target birds in the various areas. Reed and sedge warblers, 

 Cetti's warblers, water rails, cuckoos, bitterns and bearded tits were among the reedbed species that 

 were targeted. These are all present in varying numbers. On the scrapes, wading birds - little ringed 

 plovers, redshanks, lapwings, golden plovers, oystercatchers, and others have been present and some 

 have bred in the past although other species have not continued to use the area. Waterfowl such as 

 teal, coot, garganey, red-crested pochard, mallard and Canada geese are regularly found as well as 

 kingfishers, grey and yellow wagtails and grasshopper warblers 



Many fish, mammal, insect, reptile and amphibian species are resident in their respective habitats. 

 Roach is the most common fish; while mammals are well represented by both welcome (e.g. otter, water 

 vole, fox, badger, and weasel) and unwelcome (mink) species. The wasp spider, brown argus butterfly, 

 Mystacides azureus (a predatory caddis fly) and both roussel's and the slender bush cricket are 

 examples of other wildlife to be found in a man-made place well worth several visits. 



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