Thursley NNR: 22 April

A really pleasant day at Thursley Common in Surrey today (I couldn't face the prospect of seeing bugger all at the patch). My main aim was to look for reptiles and early dragonflies, but a cold fresh NE from mid-morning wind was far from ideal and I only managed one species of each - lots of Common Lizards Zootoca vivipara on the wooden boardwalks (both adults and young), and just a single female Large Red Damselfly Pyrrhosoma nymphula.

Common Lizard Zootoca vivipara - the boardwalks at Thursley Common are a great place to see them

Common Lizard Zootoca vivipara - note how this one has flattened its body to maximise surface area facing the sun

Today's female Large Red Damselfly Pyrrhosoma nymphula. The black legs help separate from Small Red Damselfly Ceriagrion
tenellum. Note the pterostigma is yellowish and not blackish - perhaps because newly emerged?

Some good birds seen today. Summer visitors noted were 2+ Hobby (hunting insects overhead), 2 Eurasian Curlew (presumably a pair on the peat bog), 1(H) Common Whitethroat (bog), 1m Common Redstart (singing around the Moat), 1 Tree Pipit (singing) and 1m Common Cuckoo. 5 Barn Swallow (mainly NW) constituted the only vis mig overhead.

Other species logged were 2 Woodlark (pair, with a male watched singing, in display flight and feeding on the fire breaks), 1m Yellowhammer (bog), 4(3m) Stonechat, Red Kite E, 2 Common Buzzard, several Linnet (a couple seen but mainly heard), 2 Tufted Duck (pair on the bog), 2+ Kestrel, 1(H) Dartford Warbler, 1(H) Siskin, Coal Tit (H), 2 Greylag Goose N, 1 Grey Heron (Moat) and a Canada/Barnacle Goose hybrid with a Canada Goose on the Moat pond.

Also, lots of Devil's Matchstick Cladonia floerkeana lichen growing on the sandy soil amongst the heather.

Devil's Matchstick Cladonia floerkeana

Rare ground beetles on Dartmoor: 13 June

Rachel and I met up with John Walters again this evening, this time to visit Dendles Wood - a patch of ancient oak pasture woodland situated on the southern edge of Dartmoor, to search for Britain's largest ground beetle - the Blue Ground Beetle Carabus intricatus. Blue Ground Beetles are nocturnal, spending the day in the soil and emerging after dark to climb the moss-covered oaks to hunt slugs. Spring to early summer is the best time to see them, when the adults are most active searching for mates¹.

Blue Ground Beetle is an Endangered Red Data Book species now restricted to just seven sites in south-west England and a single site in Wales, with southern Dartmoor being the species stronghold. They have only ever been recorded at 15 sites in Britain, and have been considered extinct more than once².

A couple of hours lamping moss covered oaks produced 2 Blue Ground Beetles, 1 Lesser Searcher Calosoma inquisitor devouring a caterpillar - a behaviour very rarely witnessed in the wild as this rare beetle tends to feed high in the canopy, 3 Ridged Violet Ground Beetles Carabus problematicus, and a single Moorland Ground Beetle Carabus arvensis. Also, another previously captured Lesser Searcher was released by John.

Tonight was quite dry so slugs were thin on the ground, apart from a single Leopard Slug Limax maximus. Also noted were a Nalassus laevioctostriatus - a Darkling (Tenebrionid) beetle, and a colony of Tree lungwort Lobaria pulmonaria.

Blue Ground Beetle Carabus intricatus, Dendles Wood

Lesser Searcher Calosoma inquisitor, feasting on a caterpillar (that was still alive when we first found it), Dendles Wood

Ridged Violet Ground Beetle Carabus problematicus, Dendles Wood

Moorland Ground Beetle Carabus arvensis, Dendles Wood - more commonly found on the open moor

Tree lungwort Lobaria pulmonaria - an epiphytic Lobariaceae lichen indicative of ancient forest, widely distributed across the
northern hemisphere and even recorded in tropical rainforest in Costa Rica (more here).

A huge thanks to John Walters for a fascinating and very memorable evening. I learn't a lot about these amazing insects and their ecology, and being eaten alive by midges was a small price to pay! For more information on the Blue Ground Beetle see John's website (where you can download some identification excellent guides) and the references below.

References

¹ Baldock, N. & Walters, J. (2008) The Wildlife of Dartmoor. Newton Abbot: Wotton Printers.
² Boyce, D. & Walters, J. (2001) The conservation of the Blue Ground Beetle in south-west England. British Wildlife 13: 101-108.