Saturday, 18 September 2010

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.

Thursday, 16 September 2010

Kick-ass Perturbation

Radipole Lake, Little Egret.

Too many of our wetland nature reserves have become ‘tired-looking’ and ‘stale’ over the years. Ongoing same-old, same-old management has allowed stability in the habitats, usually with competitive species becoming dominant. In many habitats, a degree of disturbance can knock back the natural succession and open up opportunities for a greater variety of species to flourish again. This management disturbance may mimic natural ‘catastrophes’ such as wind, flood, ice or fire, which, in the longer term, are rarely as bad as they first seem. Such ‘Kick-ass Perturbation’ (as a colleague nicely puts it) can be highly beneficial as the habitat vigorously recovers. A good example is the recovery of the Strumpshaw fish population here.

Why don’t we do more of this KP? Well, lack of resources, perhaps a fear of change, and of complaints from visitors (incl. birders) who see the changes as damaging, are some of the reasons. The first time I instructed a large excavator to re-dig an old ditch on a SSSI, I couldn’t sleep for days I was so worried about what I had done. Within minutes the black scar was extending across the land and the ground shook as each bucketful of silt was lifted. One year later the site looked fantastic, ‘long-lost’ species had returned.

Anyway, getting to the point, and on to Radipole Lake, the latest stop on the reedbed tour. On a previous assessment back in 2006, I had identified the lack of lack of structure within the reedbeds and the lack of ditch maintenance as a key factor in the site’s decline. A plan was drawn up. That plan is now halfway through implementation and the initial results look excellent. Some great looking KP has been performed on the ditches and pools. The water now ‘boils’ with invertebrates and fish, and studies of the bats has shown increased use of these restored areas by feeding Daubenton’s and Noctules. Give it 2 years and I will expect booming Bitterns.
The major distraction during the visit was the number of Great Green Bush-crickets chirping away. Lodmoor looked good, with 3 Curlew Sandpiper, 2 Spot Reds, Ruff, Redstart, Wheatear and several Med Gulls.

Below - aerial views of Radipole before and after restoration of the ditch systems.

Saturday, 11 September 2010

Patch-birders everywhere grateful to ‘little and large’ (as long as they didn’t see their legs).

Little and large at large in Bedfordshire (Steve Blain).

One particular pair of Cranes, ‘little and large’, have done much to make patch birders happy this year, from North Norfolk down to Sussex, across to the midlands, and back to Fakenham. However, a close view reveals an inconspicuous ring on one bird, revealing a captive origin.

Most would agree that Cranes are spectacular birds, well worth having roaming around the countryside. With a combination of human tinkering (a small handful of these birds have a captive origin) and a westward expanding European population, Cranes now seem to be finally getting a grip in the UK with around 15 breeding pairs this year, rearing 6 youngsters. Now splitting into several sub-groups in the UK, the total number of birds is close to 60.

Despite their size, Cranes can be remarkably elusive when nesting. They appear somewhat unfussy in choice of nesting location given a few basic parameters – the nest is usually in shallow water and some peace and quiet is near the top of their list (ie a large wetland habitat). But perhaps it is the quality of the chick-rearing habitat that is more important. Predation by Foxes has proved to be a key constraint in the UK. For the first few weeks of life, the chicks forage close to the nest. However, as they then start to roam wider, they become more vulnerable and many chicks succumb before they reach the end of the 10 week fledging period.

Monday, 6 September 2010

Roll over Rainham

This may look like a building site to you but to me this is a wide creek around 1m deep, stretching away from the sea wall, and then sub-dividing into narrower ditches and foot-drains (lower picture). Winter rainfall will fill and flood the site, draining down in summer to reveal muddy pools and edges. Specially designed scrapes will pull birds towards the viewing positions. This is the start of the next mega wetland site in Essex. This site will be special! Work started this week on Bowers Marsh to create a complex of wet grassland, scrapes and saline lagoons. Roll over Rainham.

Across the way, Vange Marsh scrape continues to pull in the birds. A shot below from last weekend shows Spoonbill, Red-necked Phalarope and Saltmarsh Goosefoot (don't believe everything you read in British Wildlife) - got them all? A quick sift through the mud and water today revealed one reason for the site’s success – food. Abundant chironomid larvae in the mud (bottom picture) and corixids (Lesser Water Boatman) in the slightly brackish water. Even West Canvey is getting in the act with a Temminck's Stint.

Thursday, 2 September 2010

Starlet steals the show

View across Havergate (with 14 Spoonbill), Avocets arriving at high tide, Starlet Sea Anemone - a rare specialist of coastal lagoons.

Equipped with sifting trays, nets and a supply of red wine, I had Havergate Island to myself for two days. The aim was to undertake a survey of the saline lagoon fauna but with a light easterly blowing, I was hoping for more.

Famous as 'Avocet island', recent years have seen a dramatic change in bird populations on the island. From zero a few years back, the island now supports 1200 pairs of LBBG and 600 pairs of Herring Gull. The increase in gulls has resulted in a corresponding decrease in breeding Avocets, Ringed Plovers and terns, due to predation. The gulls have moved to Havergate from Orfordness, where they have been decimated by Fox predation. However recent years have also seen an increase in Spoonbills, with counts here or at the adjacent Orfordness being the UKs highest, 14 were still present during the visit.

The lagoons at Havergate are also important for their specialist invertebrates. The sampling revealed a high biomass within most lagoons; ragworms, the amphipod Corophium, Lagoon Cockles and abundant Palaemonetes shrimps, but perhaps the most important saline lagoon specialist is the Starlet Sea Anemone. However, with a body only 2-3mm long, this is not the most obvious beast.

Avocets still favour Havergate for feeding, 620 were present, along with 250+ Redshank and 50+ Black-tailed Godwits. Other bird highlights included 50 Common, 26 Sandwich, 1 Arctic and 1 Black Tern, Peregrine, Hobby, 3 Pintail, 15 Greenshank, 2 Spotshank, 10 Knot, 60 Golden Plover and 28 Bar-tailed Godwit. Passerine migrants were represented by a Reed Warbler, a few Wheatears and a Rock Pipit. Could have been better, but the sunset was worth it.