Birders recently visiting Summer Leys in search of autumn migrants cannot have failed to notice a significant change in its appearance. Last week saw the completion of the reprofiling of the scrape there – a much welcomed move designed to improve this important habitat for both breeding and passage waders.
This short project, which was completed in little more than a week, was specified and managed by Steve Brayshaw on behalf of the Wildlife Trust following the last major reprofiling there in October 2007. Additional works took place in September 2008 with perimeter banks being raised and a new water control structure installed to ensure all the scrape islands could be completely flooded in the winter. This proved to be extremely worthwhile as 2009 was an excellent season for breeding waders, with at least three or four pairs of Little Ringed Plovers, eleven to twelve pairs of Lapwings and two pairs of Redshanks all raising young. Since then, however, breeding numbers have declined with, for instance, just three to four pairs of Lapwings breeding there this year.
At the time of the 2008 reprofiling the scrape was also found to be suffering from an infestation of Crassula helmsii (otherwise known as New Zealand Pygmyweed or Australian Swamp Stonecrop). This invasive non-native species is virtually impossible to control effectively and still remains a problem.
The primary purpose of the recent works was to restore the scrape to the 2008 profile – to improve habitat for breeding waders and to raise the potential for passage waders. All the vegetation (including Crassula) on the scrape islands and the majority of the margins has been scraped back to bare earth and willow saplings have been removed. Great care has been taken to ensure that Crassula does not spread outside the scrape, including cleaning down the machinery before it was moved to the next site.
Two small reedbeds have been retained but the reedbed in front of the Pioneer hide has been removed to restore the view! The water level at the time of the works was approximately thirty centimetres lower than it was when reprofiling was completed in 2008, so the channels between the islands have also be deepened slightly to increase the extent of wet margins. Heavy rain since the works were complete is already washing sand and silt out of the reprofiled soils to reveal areas of bare gravel.
Subject to the completion of other habitat management elsewhere on the reserve, including the removal of vegetation on Gull, Hawthorn, Round and Rotary Islands, the water level in the scrape will be raised by around 30cm over the next month to increase the extent of mud and shallows before the scrape is completely flooded again over the winter to suppress further vegetation growth.
Hopefully we can look forward to record numbers of breeding waders in 2014 and an excellent wader passage, with the added bonus of a rare vagrant or two. A pair of Black-winged Stilts turned up in May 2008 following the last round of reprofiling so watch this space!