Pop-up wetlands

The idea of ‘Pop –up’ or ’walking wetlands’ has been used in North America for a number of years. They are temporary wetlands where land, usually agricultural, is shallowly flooded to attract waterbirds. This has achieved benefits for both conservation and agriculture. They have been used by conservationists to provide feeding habitat for passage waders or wildfowl. The large concentrations of Snow Geese or cranes that can occur on these sites are well known.

Why do we not seem to employ similar techniques in the UK? Okay these are not natural habitats but where feeding opportunities for birds are lacking, such temporary wetlands are likely to attract large numbers of birds.  We could adapt these ideas on nature reserves. Where a reserve lacks suitable shallow floods in the autumn but has available water, why not pump water up into a temporary scrape? Can we not flood cropped areas to provide autumn habitat for waterbirds?

Dungeness is already employing a variation of
this technique with some success. The
‘hay fields’ at Denge Marsh flood naturally with high water
levels but when they are low, water can
be pumped into the fields from the
adjacent ditches.  I took a trip down to ‘Dunge’ last week to look at these fields.  They have already attracted a flock of 10 Black-winged Stilts this year and a Long-billed Dowitcher was briefly present on the day of my visit. Sadly whilst I was enjoying the delights of 2 booming Bitterns, several Hobbies, Whimbrel, Common and Arctic Terns, the Dowitcher flew away.  Arriving at the hay fields, we discussed how management could be improved (to tempt Dowitchers to stay longer). This year, the fields will be drained by June in preparation for cutting the
 vegetation in early July and
 then several areas will be rotovated.  Water will be pumped 
back on in late July and the area 
maintained wet into next spring.  This
 should provide not only good early autumn feeding for
 passage waders and other waterbirds but also allow early colonisation by chironomids to enable a sufficiently large biomass of larvae by next spring for breeding waders.

Photos above: the hay fields at Dungeness, with Black-winged Stilt.

Purple patch

Good Bitterny reedbeds, GWE and a Medicinal Leech.

And so to Dungeness, where, thigh-deep in water, counting reeds, a party of 17 Glossy Ibis passed overhead unnoticed. Reedbed creation work in the mid 2000’s is beginning to bear fruit. The improved conditions in the reedbeds has triggered the first proven breeding of Bitterns, and as a bonus, the well publicised pair of Purple Herons. PH’s have similar nesting requirements to Bitterns and although this year’s breeding will be seen as opportunistic, credit is due to the site staff for creating ideal conditions within the reedbeds. A day was spent recording the habitat characteristics around the nesting areas.  The PH nest was a sturdy platform created from bent stems of reed woven together with additional reed and stems of Great Water Dock.
It’s always good to remove the waders at the end of the day and wiggle the toes in the cool water – at Dunge you get the added bonus of watching the Medicinal Leech’s loop towards you. Little Gulls, Black Terns and Great White Egret couldn’t make up for the disappointment of missing the Ibis.