Sunday, 5 May 2013

Set Theory

Springtime Skippers Event Report 4th May 2013

Update 7th May 2013
Law of Cussedness:- I saw my first Grizzled Skipper (Pyrgus malvae) of the year in Barnes Wood today.
Origianl photograph
Enlarged and cropped


There is a mathematical construct known as the ‘empty set’. It is exemplified by the set of ‘no apples’, which unsurprisingly, is equal to the set of ‘no oranges’. For completeness, the empty set is a subset of every other set. So yesterday at my Sussex Butterfly Conservation, Springtime Skippers Event at Barnes Wood in East Sussex, I experienced the set of ‘no butterflies’; yet another fine example of the empty set.

The spring has been delayed by about a month this year and the Skippers are yet to emerge.

Grizzled Skipper (Pyrgus malvae); Currently only appearing in my dreams! Photograph by Peter Eeles; UK Butterflies
Fortunately our group contained people who are top notch on birdsong. So my heartfelt thanks to Linda, Lyn and Anna who saved the day with instructive identifications of Chiffchaff (Fringilla coelebs), Wren (Troglodytes troglodytes), the scuttlebutt among birdwatchers is that scientific name for the Wren is derived from the belief that they inhabited caves(?), Nightingale (Luscinia megarhynchos), Coal Tit (Periparus ater), Great Tit (Parus major), Black Cap (Sylvia atricapilla),Willow Warbler (Phylloscopus trochilus), Greater Spotted Woodpecker (Dendrocopos major observed) and Robin (Erithacus rubecula). My contribution was Herring Gull (Larus argentatus), which I now realise I may have called wrong. The gulls are harder to identify by their sound than I originally presumed.

Sadly no slugs this year (beautiful or otherwise), so the invertebrate interest was confined to a Green Tiger Beetle (Cicindela campestris), a White-tailed Bumblebee (Bombus lucorum), a Common Carder bee (Bombus pascuorum) and a Glow Worm larva (Lampyris noctiluca) kindly photographed for me by Nigel Symington.
Glow worm larvae Photo by Nigel Symington

Green Tiger Beetle: Photo by Heather Martin
 The (non empty) set of patient and good humoured event attendees were {Dave, Martyn, Nigel, Anna, Peter, Don, Clare, Linda, Lyn, Heather, Rodney, Lindsay, Scott and two year old Maria}.  
The Beech Woods in Vinehall Forest
Jim Barrett

No comments:

Post a Comment