Tuesday, 18 May 2010

18th May. Woodchat!

A post-meeting walk around West Canvey Marsh reserve with Marc Outten to discuss the finer points of field, ditch and reservoir edge management was stopped in its tracks as we lifted our binoculars to view a bird that had just flipped up onto the fence line in front of us; a stonking Woodchat Shrike! If only all meetings could be disrupted like this.

15th May. A 'biggish' day in the valley

Temminck's Stint at Holyfield Marsh

An attempt at a Lee Valley ‘big day’ produced a reasonable total of 103 species. A 3.00 am start to listen for booming Bitterns was disappointing but the usual night shift of Nightingales, Cetti’ s Warblers, Groppers, Sedge Warblers and Water Rails were in full voice. A couple of hours at Amwell from dawn took the list up to 60 species, nothing unusual but the highlights were 2 Oystercatchers, a Snipe, a Ringed Plover, 11 Hobby and a scarce valley floor drake Mandarin.
Holyfield Marsh produced the bird of the day; a Temminck’s Stint on Langridge Scrape, my 10th in the valley over the years, but evidently harried off by the territorial LRPs before many people saw it. A purring Turtle Dove, a Little Owl, Lesser Whitethroat and several Yellow Wagtails kept the list moving along.
Brief trips to Broxbourne Woods and Epping Forest produced singing Firecrest and Tree Pipit.
The Girling was almost bird-less but did add 2 Peregrines (one carrying prey) and 2 Common Sandpipers. A Dunlin, 2 Wheatear, a Common Gull and a Red Kite moving north on the KGV brought up the 100.
A return up the valley added 3 more species, a Marsh Harrier over Rye Meads being the final species before I gave up at 4.00 pm. Notable misses were Barn Owl, Black Redstart, partridges and Marsh Tit.
With 21 Hobbies, 12 Buzzards, 7 Sparrowhawks, 4 Kestrels, 3 Peregrines, a Red Kite and a Marsh Harrier noted during the day, the increase in birds of prey is perhaps one of the most remarkable changes in the bird populations over the years, not to mention 8 Little Egrets.

Monday, 17 May 2010

13th May. Old Hall

With 54 pairs sitting on eggs at Old Hall Marshes it might look as if this is going to be a good year for Avocets. But how many will make it through to fledging? If recent years are anything to go by, then very few. When Avocets first colonise a site they typically are very productive but as the years go by, fledging success falls away even if the number of breeding pairs continues to increase. This has been the case at Old Hall, and at many other well known Avocet sites. Some studies show food availability as the key factor, and we know that at Old Hall last year, the average biomass of Avocet food items in the pools was only a small fraction of the recommended level. So this might be the reason. However, we also know that predation is another major factor. Avocet chicks are gobbled up by a variety of predators, not least gulls and foxes.

Whilst both these factors are probably playing a part, the broader issue is that Avocets are an ‘early successional’ species, turning up and doing well at new sites before the habitat matures and brings in other species, such as gulls, or the site productivity (in terms of food availability) drops, or the predators get to know where their dinner is likely to be located. Maintaining Avocets on a small ‘stable’ nature reserve can be difficult, and involve much scratching of heads.

Whilst in such a bout of head scratching at Old Hall, we enjoyed 3 Spoonbills, 35 Whimbrel, 2 Greenshanks, 2 hunting Barn Owls (one catching a vole), 6 or more Marsh Harriers, 2 newly fledged broods of Bearded Tits, and watched the first hatching Avocet chicks. How many will survive this year?

Sunday, 9 May 2010

Crex crex

It seems bizarre to have a crekking Corncrake 2 metres from the car adjacent to a busy road. This was just one of 8 calling birds at the Nene Washes this evening. Three were clearly audible at once from the road just outside Whittlesey. With a possible 12 males back this year, the re-introduction programme is progressing but still short of the target sustainable population. I listened to one bird for 30 minutes, glimpsing its shape in the dark, as it called incessantly from the trackside grass and nettles. Earlier, a Spotted Crake had briefly ‘whipped’ in the wet sedgey fields managed specifically for it. Result!
The continuing cool weather is keeping the Snipe subdued, but the number seen clearly hinted at the importance of this site. The fields look in good condition, held back by the weather but full of waders. Around 10-15 pairs of Black-tailed Godwits revealed themselves, at least one with chicks. The supporting cast included several pairs of Wigeon, a Whooper Swan, a dozen Little Egrets, 2 Hobbies and 4 drake Garganey. The Garganey sat together on a pool by daylight but after dark made their presence felt more obviously, their rattling calls coming from all directions as they flew up and down the washes.