For the past four years, I have had the privilege of spending my summers carrying out breeding wader surveys in the Glenwherry area of the Antrim Hills. Our uplands often fail to get a mention when conservationists talk about ‘wetlands’ but that is exactly what they are and a wide range of wildlife depends upon these wet, rush covered pastures. It may come as a surprise that one of the factors restricting breeding wader productivity in Glenwherry (and in general) is a lack of easy access to wet muddy drains and pools, where birds such as lapwing forage for invertebrates. Come the late breeding season, fields can become dry and wader chicks may have to travel large distances in search of food, reducing their chances of survival.
Step forward Glenwherry farmers, who in the past four years have installed over 30 new scrapes to benefit breeding waders (with no financial incentive I might add). These have proved a resounding success not only for breeding waders but a surprising range of other species.
Wader scrapes are small (often no larger than 20m2) shallow scrapes in the ground which are intended to hold water long into the summer months. They are created using a digger to scrape off the surface layer of grass to expose the mud underneath, creating a shallow basin. This fills with water over winter and gradually recedes as the year progresses leaving wet muddy margins for wader chicks to feed in.
Image 1: Taken in October, this newly created wader scrape is deepest in the centre, ensuring it will remain wet well into the year. Scrapes are most successful when combined with habitat management such as rush control, as can be seen in the background. (Neal Warnock)
Image 2: Taken in early March, this scrape shows ideal water levels, with some muddy margins beginning to appear - much to liking of snipe. You can see their footprints in the mud. (Neal Warnock)
Image 3: Taken in early July. Even in the driest of summers, wader scrapes remain wet providing a vital lifeline to chicks in the late breeding season. This particular scrape was heavily used by a late brood of lapwing. (Neal Warnock).
Three sites which installed wader scrapes in autumn 2011 have seen the combined number of pairs increase from 10 that year, to 24 pairs in 2014. Snipe have been the main benefactor accounting for this increase. Furthermore, these scrapes are also a great attraction to overwintering snipe, with up to 40 birds recorded using a single scrape. The occasional jack snipe has also been noted.
Aside from breeding waders what else has been seen using the scrapes?
Each spring many scrapes burst into life with a chorus of croaking frogs and masses of frogspawn and by late April house martins can be seen collecting mud from their margins. In fact the first time I recorded this, I looked around and could not even see a suitable nesting building; these house martins were flying a considerable distance to and from their nest site, thus confirming my assertion that there was a lack of mud in the area!
Image 4: Common frogs can be found using scrapes for mating and spawning. (Neal Warnock).
Image 5: Masses of frogspawn can be found around scrape margins. (Neal Warnock).
Image 6: House martins require access to soft mud to build their nests. (Tom Marshall: rspb-images.com)
Another unexpected benefit has been to meadow pipits and skylarks that make use of the spoil from newly created scrapes which is spread out nearby creating small temporary plots of bare earth. This creates excellent feeding opportunities for these threatened farmland birds which thankfully are still plentiful in Glenwherry.
Moving away from birds, last summer I recorded my first damselflies in Glenwherry at a well established scrape. The species involved were blue-tailed damselfly and common blue damselfly. Could these and other species start colonising other scrapes, or could I possibly dream of recording a County Antrim rarity such as the variable damselfly?
Image 7: Common blue damselfly is an unexpected benefactor of newly created scrapes. (Neal Warnock).
Perhaps in a few years time I will be in the position to write another blog about the different kinds of surface dwelling invertebrates I see scuttling across the surface of the water, but at the moment I don’t a have a clue what they are! But I do know that creating a wader scrape is a simple, cost effective measure which enhances the opportunities for a wide range of upland species.
By Neal Warnock (RSPB Conservation Advisor, Northern Ireland).