US social scientist Kenneth Boulding : ‘If you believe exponential growth can go on in a finite world, you are either a madman or an economist’.

Friday, 6 August 2010

6/8/10: Barnehurst Beewolfs and darting Dragonflies

An unsuccessful White-letter Hairstreak hunt in a new location today - but it's getting a bit late in the season and, although warm, it was somewhat overcast during much of the time I was out.

The 'failure' was made up for by finding 2 specimens of the Beewolf (Philanthus triangulum) amidst the big colony of Mining Bees on the sandy bank between Erith Rd and Bursted Woods in Barnehurst.

Part of the site (looking north) with about a third of the bee/wasp excavations in view.

I was watching one of the bees doing more excavation work when a white face appeared at the entrance to another tunnel. I only knew what it was thanks to the LNHS Bushy Park field trip last weekend (see 31/7/2010 post). The owner jiggled back and forth several times, with a bit more of itself coming out of the tunnel mouth each time before it eventually flew off, coming back later 'empty-handed'.

Philanthus triangulum has to date been regarded as rare, and its status given as vulnerable, RDB2, with its population concentrated in the south-east (originally only in sandy habitats in the Isle of Wight and Suffolk) with a scattered distribution north to Lancashire and Yorkshire. It is now being found more often and has been reported as exhibiting more catholic tastes in habitat than previously.

One of the Barnehurst Beewolfs ('blown up' from a mobile phone cam picture). This one had landed on some excavation material, and was fairly obliging - apart from positioning itself behind some bits of grass.

I also checked out the old Pitch and Putt area along the wood margin. To my mind the mowing regime could usefully be relaxed a bit, at least in patches. There was little for insects to nectar on, apart from scattered Yarrow - which doesn't seem to be used much. The bees seen were on a couple of Common Ragwort 'stunted' by mowing, a couple of patches of Black Knapweed which I hadn't recorded here before and a few Spear Thistles in the band of Bramble/Nettle along the edge of the wood.

The heavily mown 'amenity grassland' of the former Pitch and Putt course by Bursted Wood, Barnehurst, quite unnecessarily leaves far too little for our declining Bees to feed on

One of a couple of patches of Black Knapweed, a great bee plant, here flowering at only a few inches tall due to the mowing regime. With a bit more imagination, flexibility and maybe training of contractors, surely such plants could be worked around or uncut areas left for them to proliferate in, providing more interest for people and a better living for local wildlife ......

I was also intrigued to see, along this northern margin of the wood, no less than 6 Hawker Dragonflies constantly zooming around in the same area without any signs of aggression towards one another. Although I watched for some time, none landed and a positive ID was not possible. This behaviour is, however, said to be characteristic of the Migrant Hawker, one specimen of which I saw on the nearby Grasmere allotment site a few years ago.

Some time earlier, I had seen a Common Darter dragonfly perch on a dead branch on the south margin of the wood, by the road to the hospital.

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