Amphibian Kama Sutra

Common toads in amplexus

Common toads (Bufo bufo) spawning

After emerging from hibernation in early spring, toads migrate back to their breeding ponds.

Males fight to secure mates and often outnumber the females at some sites. When this happens the female may be grasped by several males in a position known as ‘amplexus’, as they compete to be in the best position to fertilise her eggs.

Common toads in amplexus

Group of toads in amplexus

Common toads in amplexus

Spawning might look fun but can also be life-threatening!

Common toads in amplexus

Toad sex is apparently a moveable feast!

The common toad is widespread in Surrey, however populations appear to be declining. Where toad migration routes cross busy roads there can be many fatalities, and local conservation groups police ‘Toad Crossings’ at dusk to help them safely across.

Common toad crossing track

This toad was late to the party, but managed to avoid oncoming traffic

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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.

Digger Wasp Hostage

Sand digger wasp with caterpillar

The sand digger wasp (Ammophila sabulosa) paralyses its prey

We encountered another variety of sand digger wasp on the heath recently – this time Ammophila sabulosa, which uses caterpillars to feed its larvae.

Sand digger wasp with caterpillar prey

Sand digger wasps’ prey may be 10 times heavier than the wasp itself

Similarly to the spider-hunting wasp (Anoplius viaticus) it paralyses its victim with venom from its sting and buries it in a nest burrow. The caterpillar remains paralysed until the wasp larvae hatch out and eat it alive!

Sand digger wasp excavating nest burrow

Female sand digger wasps excavate a short burrow in sand

The entire nest cycle from site location, through excavation and provisioning, to finally sealing the burrow, takes 8-10 hours to complete.

Many wasps have ingenious parasitic strategies, as these earlier blog posts illustrate:

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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. 🙂

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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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Hen Harrier Fox Ambush

We’re lucky to have at least two male hen harriers overwintering on the shores of Poole Harbour this year. They’re visually quite distinct from the female hen harrier and other local raptors like the buzzard and marsh harrier. From a distance they might be mistaken for a gull as they patrol above the reed beds.

On this particular afternoon I’d been sat in a freezing hide at Middlebere overlooking a channel off the harbour with several other people. The male hen harrier passed the hide on 2 occasions as it hunted, and we were well pleased.

As the light began to fade and the temperature dropped so my companions began to leave. As dusk approached it was just me and my camera when this fella chose to alight on the neighbouring fenceline:

Hen harrier

I couldn’t quite believe my luck. It was clearly aware of my presence but seemed entirely unbothered. The bird continued to survey the reeds from its vantage point for some minutes. I hurriedly assembled my tripod and mounted the camera to switch to video mode. At which point this happened:

The harrier clearly spotted something edible in the reeds and swooped in to grab it. Either it missed, or the prey got away at the first attempt, but the harrier did not give up and flapped around after it in the reeds.

Seeing this grounded raptor the local fox recognised a golden opportunity and rushed in while its back was turned. Foxy must have come within a couple of feet of success. In the slow motion sequence you can see the harrier attempt to lift off, with the prey in its grasp, but gets snagged on the reeds with almost fatal delay. What appears to be a small mammal, probably a vole, then falls from its clutches as it finally gets airborne.

The slightly dejected, but still rather smug looking fox, then sauntered off right past the hide:

Fox

Wily fox walks away

Osprey Encounter

Ospreys are regular visitors to Poole Harbour in the autumn, en route to Africa where they flee for the winter. They’re especially well adapted for catching fish and extraordinary to watch. We’re very lucky to have them so close, but I’m not sure that many locals in neighbouring Poole and Bournemouth even realise they exist, let alone where to find them.

The National Trust have a wildlife hide at Middlebere on the edge of a channel running into the harbour. It’s tucked away in the woods opposite the RSPB’s reserve at Arne. In season the ospreys can regularly be seen commuting up and down the channel on fishing expeditions. Great to watch through binoculars and scopes, but for photographic purposes they remain a long way off.

Having watched them from the hide on a few occasions I became familiar with a regular perch nearby. After consulting maps it looked accessible and there was decent cover nearby, so I determined to get closer.

On more than one occasion I observed ospreys perched in the branches of a dead tree after arriving on site. However ospreys are quite happy to spend hours sat in the same location and are difficult to approach. This was the closest I managed to get with a long lens without spooking the bird:

Osprey in dead tree

Perched osprey (Pandion haliaetus)

To get any closer I was going to have to get into position early one morning, before the birds became active, and wait for them to come to me. Several times I hid my gear nearby – tripod-mounted camera at the ready – and waited fruitlessly for a bird to appear.

On this particular occasion I was late to arrive and could see an osprey already in position.

Osprey perched in dead tree

Osprey (Pandion haliaetus) in dead tree

Having snapped a few long distance shots I might have turned back at this point but they’re beautiful birds to watch, even at a distance.

By the time I’d crept to the next viewing position the osprey had flown, but I seized the chance to scurry into position deep in the reeds, close to the dead tree perch, and hurriedly assembled tripod, camera and improvised camouflage. Pulling the reeds back over my head I settled in for what I thought might be another long, uneventful afternoon.

But within 20 minutes I saw a large bird flying in low over the reedbed. Through the binoculars I could make out a large wriggling shape in its grasp. It could only be a returning osprey!

I ducked down out of sight and watched the perch on the camera’s LCD monitor. Nothing. Wrong branch! Swivelling the lens to the left brought this majestic osprey into focus, a freshly caught bass pinioned in its enormous talons:

Osprey with bass

Osprey (Pandion haliaetus) with freshly caught bass

Over the next hour I was privileged to watch this mighty bird devouring its meal at close quarters, and captured some memorable stills and video footage in the process:

Canon 550D | Canon EF 100-400mm f4.5-5.6 L | Adobe Premiere Pro

The reedbed was enveloped in low cloud or mist and – together with the hissing sound of the reeds in the gathering wind – the conditions heightened an already surreal, unearthly atmosphere. Something I will never forget.

I didn’t dare to pan away for wide shots during the encounter for fear of spooking the bird, so had to improvise the cutaways. Editing an hour’s footage into a few minutes was surprisingly difficult.