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!

Related links:

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.

White Sika Winner

I was exceedingly pleased to learn last week that my image of a white sika deer won the RSPB’s ‘Picture Arne’ photo competition, judged by wildlife broadcasting legend Mr Chris Packham!

White sika deer

Blondie

There are several white sika in the area surrounding Poole Harbour in Dorset. They are a ‘white morph’ since they don’t have the red eyes one would expect in a true albino.

Sika deer (Cervus nippon) are not native to the UK but escaped from captivity on nearby Brownsea Island some decades ago, since when they have made the Isle of Purbeck and surrounding area their home.

The RSPB’s reserve on the Arne peninsula supports a number of scarce species – most notably the dartford warbler (Sylvia undata), but also heath-loving reptiles such as the sand lizard and smooth snake.

I stumbled across this scene late one sultry August evening last year whilst returning home from another photographic project. The young sika stag was browsing in a meadow, accompanied by a small group of other more conventionally coloured deer.

Taken with the Canon EF 100-400mm lens.

BBC Wildlife Magazine: Peregrine

One of my recent peregrine photos appears in this month’s edition of BBC Wildlife Magazine, illustrating an article about the remarkable international success of this species across a range of different environments – both wild and urban:

BBC Wildlife Magazine - Peregrine in Flight

My image of juvenile peregrine in flight top centre. Taken along the Dorset coast last summer.

Available now at all good newsagents! 🙂

A Dorset Christmas

Dorset Wildlife Trust’s new collection of Christmas cards for 2011 includes one of my recent landscape photographs:

This was the wintry view from Swyre Head in the Isle of Purbeck looking west to Kimmeridge Bay, and Lulworth beyond, back in December.

This design and others are available to purchase from the Dorset Wildlife Trust’s online shop in packs of 10, with profits going to the charity.

The snow did not settle for long, and by the following afternoon was in rapid retreat.

Images of Durlston

I was delighted to be voted Winner in the Spring / Summer 2011 ‘Images of Durlston’ photo competition earlier this month, with this image of a juvenile peregrine patrolling the clifftops:

Juvenile peregrine in flight

Juvenile peregrine in flight on clifftops

Durlston Country Park and Nature Reserve is located on the south coast of Dorset just outside Swanage.

I was fortunate enough to be a regular volunteer at Durlston for more than 2 years. This shot was taken on a brief return visit in July of this year, with a Canon EF 100-400mm lens and a bit of luck.

Two peregrines fledged in the area this year and could regularly be seen from the coast path over the summer – alternately terrorising the nesting seabirds on the cliffs below and testing their new wings in mock aerial combat with each other, and with their increasingly unamused parents.