Mike Dilger’s wildlife watching
In his series of great places to watch wildlife in the UK, the star of BBC One’s The One Show this month reveals why flooded grazing marsh is a great place to spot migratory birds wintering in the UK.
Find out which avian species are at home in flooded grazing marsh
Watching huge flocks of ducks, geese and swans swirling across wide, open skies, before alighting on the flat, expansive sanctuary of a flooded grazing marsh, has to be among the finest of all early winter British wildlife spectacles. At first glance, these winter wetlands look wild and untouched but, like so many of our habitats, they are another example of human dominion over nature, which has, on this occasion, fortuitously transformed them into vital wildlife refuges.
Defined as being pasture land frequently flooded in winter, grazing marsh comes in two distinct forms. Occurring in any flat areas alongside the coast, coastal grazing marshes were historically saltmarsh before then becoming hemmed in behind man-made sea defences. By contrast, inland grazing marshes tend to be located around low-lying rivers and lakes, and would have historically been swampy woodland, fen or reedbed, before medieval folk intervened.
Created, and still primarily used, for pasture cattle, both grazing marsh types are also characterised by the presence of ditches or dykes, which were originally dug by hand to drain the land. The remaining water is then controlled through the use of pumps and sluices so that, even during the hottest summers, most ditches should still be filled to the brim with either fresh or brackish water.
As most grazing marshes have historically been ‘improved’ with fertilisers to enrich the sward for cattle, their botanical interest can be fairly limited. However, the expansive network of ditches frequently contain a richer mix of aquatic plants and, in many cases, a glittering array of rare water beetles. But the vast majority of naturalists’ interest in grazing marshes is due to their importance for a range of migratory birds, which will have arrived from right across the northern hemisphere to spend the winter in a habitat offering both food and protection in abundance.
The extensive and shallow flooding occurring in winter is particularly attractive to birds that either dabble, graze or fish for a living. These species can feed in full knowledge that most terrestrial predators are simply unable to access their watery world. It also makes any sneak attacks infinitely more challenging across the open landscape, particularly when so many pairs of eyes are on the lookout for danger, too.
Of the approximate 220,000ha of grazing marsh remaining in England, a high proportion of the best sites are now either nature reserves or within environmental stewardship schemes. But there is no room for complacency
at other marshes with less protection, as over-zealous draining or unsustainably high stocking levels can result in their attractiveness to wildlife rapidly diminishing. Also, the omnipresent spectre of climate change now means coastal grazing marshes are becoming evermore vulnerable to the threat of inundation from rising sea levels.
With access obviously limited across grazing marshes, undoubtedly the best way to enjoy the wildlife on offer at this time of year is from the outside looking in. Many reserves offer hides with marvellous views, but do bear in mind that well-trodden bridleways and footpaths can also offer disturbance-free viewing, while preventing that feeling of claustrophobia and tunnel-vision that can occur from peering out of what is little more than a large wooden box.
Finally, due to the sun featuring lower on the horizon with each passing day, knowing your east from your west will ensure that, instead of being blinded by the light, you will be able to enjoy the rich colours on offer.
The vast majority of naturalists’ interest in grazing marshes is due to their importance for a range of migratory birds.