Monday, 25 April 2011

2,120 miles and counting.

I hate the rezzers. I wish I wasn’t stuck with reservoirs in my local patch. All that concrete and water, and nothing else, not a bush in sight. A visit in spring to these concrete doughnuts may yield little more than 5 species actually on site. The faster you walk to get around, the more you gag on irritating little midges that lodge in your throat.

While watching Eastenders the other night I decided to look through a few old notebooks to see how many times I’ve visited the rezzers. By a fag-packet calculation I reckon I’ve walked 2,120 miles around those sodding banks over 40 years. I’m now catching up with the boys of the past – John Fitz, Phil Vines, Tony Gray. Legends. Where are they now? Probably still so bush-intolerant that they can only stare out to sea from coastal retirement homes.

However, with all that superfluous breeding and resident stuff stripped away, what you get is birds on passage. Some of my best spring vis-mig days have been down there. On a lovely late April day with drizzly north-easterlies and low cloud, stuff can pile through. Hordes of Yellow Wags eating the pesky midges, waders zipping through without a tree to hide behind, and, after lunch, Arctic Terns arriving, gathering, then moving off north (never trust a man who sees an Arctic Tern early in the morning).  In fact, I can’t wait to get back down there.  I love the rezzers.

A sample good day:
3rd May 1980. Strong NE-E wind, cloudy, some drizzle.
King George V (early morning): 2 Oystercatcher north, 1 Sedge Warbler on bank!, 1 Sanderling, 16 Common Terns north, 1 Wheatear, 5 Turnstone.

Walthamstow Res (late morning): 1 Bar-tailed Godwit (on the deck), 4 Ringed Plover, 4 LRP, 1 Turnstone, 6 Wheatear, 1 White Wagtail, 5 Shelduck.

Girling (afternoon): 1 Ashy-headed Wagtail with 30 Yellow Wags, 1 Whimbrel north, 1 Greenshank, 2 Wheatear, 1 Turnstone, 27 Bar-tailed Godwits north, then 100+ Bar-tailed Godwits north.

Below - some recent stuff on the King George: White Wag, Dunlin, Ring Ouzel, Little Gull.

Wednesday, 20 April 2011

Boom boom boom boom

Night to day: moonlight, sunrise, feeding Great White Egret, Hairy Dragonfly.

Not John Lee Hooker but the Avalon Marshes in the middle of the night. The colonisation in recent years by Bitterns of this wet patch of Somerset has been a remarkable conservation success. As I stumbled around in the darkness as part of a co-ordinated survey to listen and watch for Bitterns, my personal tally was 12 ‘boomers’ although the area total may exceed 20 by the time all the results have been analysed.

When it comes to surveying Bitterns, the key census ‘unit’ is the booming male. There has been a complete count of booming Bitterns in the UK since 1990, from the low point of 11 boomers to the current high of 87 last year. Territories can overlap and males can be mobile so difficulties can arise sorting the individuals out. Survey results are drawn from careful mapping of boom locations combined with details on the characteristics of each individual bird’s boom. Booming reaches its peak around dusk and in the two hours before daybreak, but blundering around a moon-lit wetland has its advantages other than the repeated humpff humpff humpff coming out of the reeds. Cetti’s, Sedge and Grasshopper Warblers belt it out alongside the Marsh Frogs, a rattling Garganey flies over, and there’s always the chance of a whipping Spotted Crake. As day breaks, Little, Cattle and Great White Egrets all enter the notebook. As we settle in for a long watch over the reeds, my first Hairy Dragonfly and Red-eyed Damselfly of the year zip along the nearby ditch, and the water seems to ‘bubble’ with fish fry.

By contrast, the other, and arguably more important, census ‘unit’, the nesting female, is a much more difficult thing to quantify. When the eggs hatch, females are likely to make regular flights from the nest to feeding areas. A watch of around 6 hours is required to assess if such feeding flights are occurring. These may then need to be repeated every week or so to try and assess if the nest is successful. Watches suggested the first nests are now hatching in the Avalon Marshes. The likelihood of a successful nest is a relationship between habitat quality, food resource and predation. At the moment, the Avalon Marshes seem to have everything going for them.

Saturday, 16 April 2011

A Budget announcement from Rainham

New hide at Rainham - just the most important bit left to do - habitat providing close views.

A worrying line of thinking in reserve management at the moment goes along the lines of: “this is a visitor-focused reserve so we don’t need to worry about the ecology” or similar. Complete tosh, of course. A reserve that delivers on its ecological potential will more effectively deliver on all it’s other functions.

Hence the continuing work to review the hydrology at Rainham Marshes. There is a need to deliver both the ecological and visitor objectives - wintering birds, breeding birds, passage birds. A variety of feeding and viewing opportunities around the reserve throughout the year – and water is the key. Yet this is a reserve in a dry part of the country with a limited resource of water. But the good news is that a ‘water budget’ shows that there should be enough water if it is used carefully and strategically. Wise use of the inputs (rainfall, surface flow), while minimising the outputs (evapo-transpiration, seepage) and ensuring stored water can be moved efficiently around the reserve is a key element in the management plan. Scrape design and location needs to take account of minimising water loss as well as providing close views.

Work undertaken on the Target pools last winter looks good – water is being retained longer and is now drying to create habitat for spring passage waders. Further work will look at re-provisioning for early autumn. With a new hide on Purfleet Scrape, careful thought is now being put into creating a much enhanced habitat that will deliver through the seasons. The existing scrapes require further ‘tinkering’ to get the best out of them.

A reserve warden I was speaking to recently complained that none of his visitors were interested in wildlife any more. Well sadly, the reason for this is that his reserve is managed like a country park – all access and signage, with no thought given to managing the wildlife. Isn’t there a clue in the name ‘nature reserve’? Visitor focused reserves need even more thought on the ecological side to ensure they are delivering on what people want to see – wildlife.

It was a great day to potter around Rainham prodding and poking at sluices, water and soils. A Greenshank landed in front of us, a Garganey flew by in a small party of Teal and Yellow Wagtails, Sand Martins, a Grasshopper Warbler and 10 Wheatears all added to the spring feel.

Friday, 8 April 2011

Instability, transitions and trash

Get in there boy.

So, our 2-year project looking at the biodiversity of reedbeds has finally delivered its results...and we can at last squash an ongoing grumble about Bittern management and reedbeds. There has been a repeated accusation that management for Bitterns is bad for reedbed invertebrates, especially moths such as the Fenn’s Wainscot. Finally - there is NO evidence for this.

The headline results of the study are as follows, with the details here:

• The older, drier parts of the reedbed contained higher overall invertebrate diversity and many invertebrates with conservation status.

• Early successional reedbed is important for reedbed and wetland specialist invertebrates.

• The results show that having a variety of ditches and open water bodies is important for aquatic invertebrates and macrophytes.

• Reedbeds are dynamic ecosystems and temporal and spatial variation in habitats is key to maintaining high diversity of flora and fauna.  Management that maintains a range of successional stages will maximise the conservation value and biodiversity of reedbeds.

So, much as we had expected.

At a recent workshop with national invertebrate experts to discuss the project results, some key management themes to benefit inverts were outlined – in my words - 'instability, transitions and trash'. Now regular readers will recognise this as music to my ears.

Instability - we should accept that habitats change; managing a habitat to maintain a stable state of the natural succession, at whichever stage, will not work. Successions need to move on.
Transitions - gradations within and between habitats often support many specialist and scarce species; brackish to fresh, tall to short, wet to dry, new to old etc. etc..
Trash - 'catastrophic' management of part of the habitat to reset it to an early successional state will allow species to colonise at the appropriate stage.  As one of the entomologists stated ‘if it doesn’t spread, it’s dead’.

I have increasingly believed that the nature reserve system in the UK (all organisations) is creating a series of stable, increasingly dull sites. We need to inject some dynamics into the system, create early successional habitat. Heterogeneity is what we want, but homogeneity is what our systems tend to deliver. The more heterogeneity in the habitat, the more species a site will support. We have become scared of disturbance.

Sunday, 3 April 2011


There has been some speculation as to whether Snake's-head Fritillary is a native plant in Hertfordshire (or indeed the UK) due to its rather late date of discovery. However, it was formerly known from a number of localities in the southern and central parts of the county. It was first recorded in Hertfordshire near Northaw in 1815 and it still (just) survives in this locality, probably its only remaining location where it may be native. I last visited this site in 1998 when 59 flowering plants were seen. After some searching, I re-found it today and counted 36 plants. However, the damp, rough paddock it frequents is neglected, and fast becoming covered in bramble and without management this looks destined to become another lost site. Meanwhile, in Stocking Springs Wood, a fine show of Wild Daffodils.