Monday, 9 February 2015

Physcia aipolia and writer's block

For the blogger concerned with sport, politics or show biz, early February is as good a time to be writing as any other time of the year. For someone whose main focus is wildlife there is a bit of a problem, although the birder has lots of opportunities to post something of real interest. For example, I can thoroughly recommend Neil and Eleanor McMahon's blog at

I do enjoy birding but do very little nowadays; for me plants and invertebrates are my passion - and this is not the most favourable time of the year to be blogging about these topics without being repetitive; there is a limit to what can be said about mosses and lichens if, like me, you are a tyro regarding these organisms. And let's face it, for most people they are a bit dull.

Anyway, on a lovely sunny morning I set out, ever optimistic, to visit Stefen Leys Pocket Park. I hesitated: should I take a sweep net for insects? In the event I decided against it and it was probably a wise decision.

In fact there were one or two flies about, generally basking on a sun-bathed tree trunk but nothing that struck me as out of the ordinary. This female blowfly is probably Calliphora vicina, a very common species. I just managed a photograph before it took off, preventing a closer examination.

The pocket park boasts a small pond, perhaps it will see frog or toad activity in the next few weeks. A slight bluish tinge to the water surface suggested a bit of pollution, although an oily film like this can develop naturally as organic materials decompose. 

Lesions on the trunk of an ash tree.
 Stefen Leys pocket park,
Daventry.  9 February, 2015

The trunk of an ash tree bore some nasty-looking lesions. It could be Ash Dieback, a disease caused by the fungus Chalara fraxinea, but I am by no means convinced. I'll have another look when the leaves begin to develop. If it is Chalara, I'll need to report it to the authorities.

There was a great deal of birdsong as a wound my way slowly along the various tracks in the park. Each male is staking out a territory and warning off potential rivals. This will intensify over coming weeks as day-length increases. I could easily have spent a pleasant half-hour watching them about their activities but...

Physcia aipolia at Stefen Leys pocket park,
Daventry. 9 February, 2015

...the lid of a litter bin caught my attention. These are made out of some sort of fibrous compound and seem to be a congenial home for lots of lichens. Even a brief glance showed five species present including this Physcia aipolia. This is commonly found on trees but seemed quite happy on its lid.

Damn! I wasn't going to mention lichens but with its black ascocarps, neatly white-rimmed, I couldn't resist it. The thallus (the white structures forming the bulk of the lichen body) looks grey-white, but under the microscope there is a hint of blue together with white speckles. A rather smart species.

I always say you can't beat a good litter bin to round off a morning's walk, so I went home well satisfied, and my writer's block cleared.

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