The Brede Valley

JUST ADD WATER

by Cliff Dean - 01.08.06

The Yeakell & Gardner map of 1778-83 shows the eastern angle of the Brede’s confluence with the Doleham Stream occupied by a series of narrow marshy meadows separated by ditches fed from springs which issue from the Lidham slopes. This pattern persists to the present day, but for the construction of the railway, which curves around the contours in a series of wooded cuttings.

Although there are footpaths nearby, most of this area is inaccessible to the public, but in early 2005, with the permission of the landowner, Philip Newton, I began a monthly Birdtrack count there - you can find more information about these counts on the British Trust for Ornithology website www.bto.org.uk/birdtrack I could see that such an undisturbed stretch of land, comprising a range of habitats, would attract an interesting variety of birds and I knew that Philip intended to raise the water levels, which would make it even more appealing.

At that point, a number of small pools had been excavated to attract waterbirds, but the surrounding rushy fields remained quite dry, and nothing much happened. The tall reeds in the ditches were occupied by Reed Warblers and Reed Buntings, and the vegetation along the railway line provided nest-sites for a range of woodland birds, but there were few ducks or even Moorhens.

During early 2006, however, Philip managed to install some bunds, which would retain more water without flooding his neighbour’s fields. The effect was dramatic. The water level rose, rush seeds floated to the surface and he phoned one evening to inform me that, not just a few, but hundreds of ducks had arrived. The previous winter had seen a handful of Mallard and Teal, but now the latter were present in large numbers, accompanied by numerous Shoveler and smaller numbers of Gadwall, Wigeon and even Pintail - a species which has formerly been quite scarce in the Rye Bay area.

The birds had obviously found something worth eating, for they were most reluctant to fly, and when forced to would just flutter a short way to find refuge in the tall rushes. Unfortunately, those same rushes and the ducks’ reluctance to take to the air made it very difficult to count them, and flocks were obviously commuting between here and other local wetlands, so counts varied from time to time and day to day. It was clear however that the management had proved a spectacular success.

My Birdtrack counts suffered as well, since my route was now blocked by deep water, which might have proved easier to navigate had it not been for deep ruts left by machinery during the previous year’s pond-digging. Before, these had merely threatened a broken ankle, but to this risk was now added the prospect of shipping a wellie-load of freezing water (it hurts). Wildfowl numbers dropped sharply at the end of March, but other species moved in to breed, some for the first time and others in increased numbers. The continuing presence of a few Shoveler and Gadwall gave rise to the
(unrealized) hope that they might breed, but they were joined by Little Grebes, Mute Swans, Canada & Greylag Geese, Shelducks, Tufted Ducks, Coots, Moorhens and Water Rails.

Floodwater on grassland by the Brede brought in a few migrating waders, and also Lapwings, several pairs of which stayed on to nest successfully. Black-headed Gulls looked interested but did nothing.

Meanwhile, the area was being visited by raptors other than the usual Kestrels, Sparrowhawks and Buzzards. Marsh and Hen Harriers began to patrol the flood, while a Peregrine, which regularly terrorized gulls and Woodpigeons on a neighbouring farm, helped itself to a few Lapwings. Later
Hobbies arrived, to feast on the myriad dragonflies.

Many other small birds used the area, irrespective of the flooding. Two particular delights were a pair of breeding Stonechats (very scarce in inland Sussex) and a Golden Oriole flying back and forth across the Doleham Valley one sunny morning.

By early July some of the pools had dried out, and the water had receded enough for me to recommence my survey route. The springs have kept running well through the dry weather, and the lack of rain we have experienced in recent years makes it hard to predict the effect of more normal rainfall.

It remains to be seen whether next winter will bring similar numbers of wildfowl. Maybe the first-time flooding brought to the surface an unusually rich harvest of seeds, but nevertheless a growing number of wetlands created in the area support an ever-expanding population of winter birds.

In the meantime, autumn migrants will move through or over the valley, providing such pleasures as chats and warblers in the rough vegetation, waves of Skylarks overhead and furtive, chattering Ring Ouzels in the hedgerows.

2007 Update. - 23.10.07

It wasn’t a one-off or temporary effect; large numbers of wildfowl returned in the winter of 2006/7.

What’s more, the high rainfall of spring & summer 2007 kept the fields wet, providing invertebrate food for up to 15 pairs of Lapwings, most of which nested on a meadow alongside the Brede but others on a nearby arable field. Skylarks and Yellow Wagtails were attracted to rough ground for the first time and up to 4 Water Rails were calling from the rushes. Canada and Greylag Geese and Mute Swans were once more on territory but don’t seem to have produced young; Gadwall and Tufted Ducks too were skulking in the rushes and probably bred.

However, there are many predators at work in the valley: numerous Carrion Crows and Magpies, Foxes, Badgers, Mink and Feral Boar, so ground-nesting birds are lucky to raise young.

Some habitat management has been undertaken during the last year by The Maxfield Nature Conservation Trust to further improve the site. A tall hedgerow running along a ditch halfway across the marsh has been removed. This opens up the area, making it more attractive to wading birds, and removes a vantage point from corvids seeking to predate their eggs and young.

“Just Add Water” sounds all very easy, but “Light the Blue Touch Paper” could be equally apt, for the combination of fertile alluvial soil and plentiful irrigation leads to an explosive growth of rush, reed, willow and alder. Some rush has been scraped away to expose small areas of mud and open water, and it is planned to cut back more in other meadows to provide a mosaic of varied vegetation. In addition, cattle and sheep have been introduced, to graze back new growth, poach the muddy areas and leave dung for insect life, which then provides food for birds. Nest-boxes have been installed on the edge of the marsh in the hope of attracting the ever-scarcer Tree Sparrow as a breeding species.

What can be achieved by enhancing a relatively small area of habitat was demonstrated in early May when I made a visit with Trevor Buttle, who used to go birding in the Brede Valley back in the 70’s. It was then a wilder place overall, with breeding Snipe and Redshank, but less varied. Trevor was as astonished as I was when we found 73 bird species in just one morning in just that one little corner.