Spring Wood Ant Antics

Wood ant with heather seed

Wood ant (Formica rufa) foraging in early spring

The wood ant mounds among the pine trees were beginning to stir on my visit to the RSPB’s Arne reserve in Dorset recently.

Nests become active in early spring when worker ants begin to forage for food items and building materials to repair damage sustained over the winter months. Badgers, magpies, jays and other animals often raid wood ant nests for food.

Wood ant carrying twig

Wood ants are capable of carrying relatively heavy loads

Wood ant colonies can contain up to half a million individuals.¬†On sunny days worker ants ‘sunbathe’ at the nest entrance to absorb heat and then re-enter the nest to release it – keeping it at a steady temperature. When the nest becomes too warm they open small vents to cool it down.

Wood ants at nest entrance

Sunbathing worker ants at nest entrance

The ants are particularly aggressive in springtime as they re-define their territories. Sometimes ants from weaker neighbouring colonies are recruited by force and carried back to the main colony.

Worker ant carrying another wood ant between nests

This species of wood ant is classified as Near Threatened (NT) in the IUCN Red List and classified in Great Britain as Local. Numbers seem to be increasing in the south of England but it has become locally extinct in parts of its former range in the north and east of England, the Midlands and north Wales.

Photographing ants is always a challenge because they’re small and they move very fast. It’s a good idea to keep your trousers tucked firmly into your socks when lying on the ground this close to a nest full of them! They will bite occasionally but can’t pierce skin. The formic acid they squirt in defence is too weak to harm humans.

Springwatched

Spider hunting wasp with spider

Spider hunting wasp with paralysed arachnid prey

The team at BBC’s ‘Springwatch Unsprung’ programme used a sequence of my photos to illustrate the intriguing behaviour of the spider-hunting wasp, Anoplius viaticus.

This solitary wasp targets spiders, which it paralyses with venom and then hauls back to its subterranean nest burrow. Once wrestled inside the female wasp will lay its eggs on the spider’s body for its larvae to eat when they hatch.

Bug expert Nick Baker explained that this species stores its prey before excavating the burrow and so the unattended spider often becomes the victim of a tug-of-war between Anoplius viaticus and other opportunistic wasps and ants.

BBC Springwatch studio broadcast

Chris, Nick, Michaela, Martin and the Springwatch gang

Natural history superstar Mr. Chris Packham then related the curious fact that one of his first ever TV assignments was to film this invertebrate behaviour on nearby Studland Beach – this being made all the more awkward because it’s also frequented by enthusiastic naturists!¬†Happily this particular site was a safe distance to the north on the peninsula. ūüôā

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Dorset Life: Hunters

A selection of my images illustrates an article about predatory animals and plants in the May edition of Dorset Life magazine, out this month.

Dorset Life magazine

Dorset Life: Dorset Hunters. Double spread I

Dorset Life magazine

Dorset Life: Dorset Hunters. Double spread II

Featured flora and fauna include: the kestrel, adder, red fox, otter, sundew, kingfisher and hornet robberfly.¬†Words by Jo√ęl Lacey.

Available now at all good newsagents and supermarkets in the Dorset area!

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RSPB Panels

Interpretation panels

Interp panels at RSPB Arne

The RSPB’s reserve at Arne in Dorset recently requested the use of my wetland wildlife photos for their new seasonal interpretation panels. They also commissioned a stitched panoramic landscape image to¬†highlight landmarks visible from their¬†stunning observation point overlooking Poole Harbour.

Featured above are the southern hawker dragonfly, osprey, wasp spider, raft spider and marsh harrier, all of which can be found on the Arne reserve at different times of the year. Well worth a visit.

Raft Spider Life Cycle

Raft spider on pond surface

Raft spider on pond surface

You’d¬†think that arachnids and water was an unhappy combination, but one species of¬†European spider has¬†made boggy ponds¬†their¬†home.

The raft spider (Dolomedes fimbriatus) is the UK’s largest native spider – its body growing up to 2cm long.

It uses the water’s surface like other spiders use their webs – feeling for the vibrations of potential prey with front legs extended. Using this technique it hunts tadpoles, insects and occasionally small fish:

Raft spider eating damselfly

Raft spider eating damselfly

When alarmed, the water repellent hairs on the raft spider’s legs enable it to dive beneath the water, trapping a bubble of air to keep it alive until the coast is clear and it cautiously re-emerges:

The wetland pools favoured by raft spiders are increasingly rare in this country. On the RSPB’s Arne reserve in Dorset their habitat is lovingly preserved, and offers wildlife watchers easy access from the nearby heathland trail:

Boggy pond habitat

Boggy pond habitat

On a good day dozens of raft spiders at various stages in their life cycle can be witnessed at the pond’s edge.

1. Sex

The female raft spider is often considerably larger than the male and mating is a dangerous business. He approaches her cautiously, waving his front legs tentatively to judge her receptiveness:

Male raft spider approaches female

Male raft spider approaches female at her den

She may rush out to scare him off on¬†numerous occasions, after which she retreats and the process begins again, the male edging closer all the while. It’s a nerve jangling thing to watch, let alone participate in.

2. Birth

The female spins a silk bag to contain the fertilised eggs, which she carries about beneath her body, keeping it just warm and moist enough to ensure their survival:

Raft spider carrying egg sac

Raft spider carrying egg sac

Then, when the baby spiders are ready to hatch, she lashes the egg sac to vegetation at the edge of the pond and the tiny hatchlings emerge:

Baby raft spiders in nursery web

Baby raft spiders in nursery web

Mum¬†typically lies in wait nearby to ensure that her young ones don’t come to any harm:

Raft spider guards her hatchlings

Raft spider guards her hatchlings

This phenomenon of hundreds of spiderlings crowded together for their own mutual safety is only really appreciated up close:

Raft spider hatchlings

Raft spider hatchlings closeup

But soon the young raft spiders are large enough to fend for themselves and disperse around the pond.

3. Death

Raft spiders are not fussy eaters. When times are tough and food is scarce, or when too many raft spiders compete for the same local resources, they may even turn to cannibalism:

Not such a pretty sight!

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Arne Claypit Reclamation

The Arne peninsula in Dorset juts out into Poole Harbour, separating the Wareham channel from the main body of water. Right out at the tip, concealed by the remains of ancient oak woodland, lies a former ball clay pit.

The extraction company Imerys finished mining the deposit in 2008, and since 2010 have been restoring the area as part of their mitigation agreement, before transfering ownership of the site to the RSPB, who manage the surrounding nature reserve at Arne.

Arne Claypit

Arne Claypit

I was asked to document this reclamation process on behalf of the RSPB, in particular the flooding of the claypit basin with water from the harbour to create a saline lagoon habitat for wading birds and other species.

With mining activities ended the pit was re-profiled with heavy earth-moving equipment, and a layer of topsoil deposited above the expected final water level in the summer of 2011.

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Next a channel was cut through the embankment to join the claypit with the harbour at the south end of the site. On especially high tides the water from the harbour would flood this channel to gradually fill the lagoon.

This process was expected to take many months and it was decided to document the process with a timelapse camera.

We surveyed the best location for the camera –¬†somewhere with a¬†wide view of the pit, a glimpse of the harbour in the background, a small island in the middle ground and some vegetation in the foreground to provide¬†varied visual interest.

Unfortunately this necessitated pointing the camera due south, so we also calculated the position and angle of the sun in future months to try to minimise its dazzling effect on the camera’s¬†lens and sensor.

Arne claypit timelapse project plan

Arne claypit timelapse project plan

The pit itself is off-limits, but there is public access to the surrounding area and it is too remote to monitor. Exposure to the elements over such a long period was also a consideration, so an expensive DSLR setup was not a practical option, and a relatively cheap-and-cheerful alternative was sourced.

The pit filled much more rapidly than the engineers had predicted and in April of the following year, after only 7 months, the rising water had achieved its final level.

The following video sequence shows events over that period, compressed to just 1 minute, using stills taken at 3 hour intervals:

The island habitat is already frequented by shelducks, and sika deer regularly visit its shores. It will take longer for the waters to settle and for other species to establish themselves.

It’s hoped that the regular interchange of water¬†with the harbour will prevent the process of eutrophication, which would otherwise make the lagoon inhospitable. The suspension of clay particles in the water can be a serious problem in this respect.

Arne Claypit Sequence

Arne claypit reclamation stills sequence

Whether this industrially exploited area becomes the wildlife oasis hoped for, only time will tell.

With thanks to Mark, Rob, Damon, James and Em at RSPB Arne.

Talbot Heath Inquiry

Talbot Heath lies largely unnoticed on the outskirts of Poole¬†in Dorset. Once upon a time it formed a seamless whole with the¬†famous expanse of heathland familiar to Thomas Hardy and his contemporaries. Nowadays it’s sliced apart by bypass and railway to north and south, and nibbled away at by encroaching residential developments to the east and west. The sea of heathland has become an island here.

Most of the locals clearly love this precious green (and brown) open space, but its close proximity to human habitation regularly puts the heathland flora and fauna at risk from fire and other degradations. The effects of arson in particular, but also the predations of local cats, litter and path erosion present a considerable threat to this Ramsar and SSSI designated site.

The local borough council in their wisdom recently approved a planning application to extend a housing development in the north, onto farmland which currently serves as a buffer between urban and heathland areas. This decision was controversial for several reasons, but especially because it appeared to override a government directive which prevented new developments within 400m of heathland sites.

The RSPB and other conservation bodies became worried that this development might set a dangerous precedent and the decision eventually went to a Public Inquiry. As part of their submission to the Inquiry I was asked to document the site photographically for the RSPB and their partners at Natural England.

Following 3 visits to the site in late spring 2011 I delivered a library of 300+ images, depicting the Talbot Heath landscape, its flora & fauna, human visitors, and urban effects.

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Update: In February 2012 the proposed development was refused permission by the Secretary of State for Communities and Local Government.