Ups and downs – survey bias or annual fluctuations?

      Adders tongue (Ophioglossum vulgatum) thrived in 2007 on our lovely meadow at Milden but there wasn’t a single spike this year. Ladies smock (Cardamine pratensis) puts up a few flowers in a damp depression in the same meadow most years but this year has surprised us, flowering all over the place including our very dry lawn. Bee orchids were abundant on clay spoil around our pond in 2008 but barely a flower head in 2009.

      White tailed bumble bees (Bombus terrestris) seemed very frequent this spring but the mason bees (Anthophora plumipes and Melecta albifrons) were very thin on the carpet (literally, for this is where they emerge from our wall and crawl around until rescued). This 2009 spring pied shieldbugs (Sehirus bicolour) appear more frequent on the farm whilst I barely saw one in 2008; and I haven’t seen a woundwort shieldbug (Eyacoris fabricii) for two years on the farm, whilst previously I saw them frequently, mating on woundwort leaves. This year’s big up so far has been the cardinal beetle (Pyrochroa serraticornis) which I have found on nettles and hawthorn leaves in far higher numbers than previously on the farm.

      I’ve seen more frog and toad tadpoles during my Suffolk pond surveys than I’ve seen in years – and fewer great crested newt. It does make one realise just how sensitive these species must be to factors way beyond our knowledge.

      We have four pairs of swallow this year (up from last year’s two pairs) and no house martin at all – down from 17 pairs last year. I’ve heard the cuckooonce; I’ve seen a pair of spotted flycatcher and thought they’d return to last year’s nest – both cuckoo and flycatcher moved on.

So are these very localised, commonly occurring, real, annual fluctuations (as I suspect) or simply the survey bias of an unscientific naturalist who takes opportunistic walks, at random times in varying weather and keeps unempirical notes on scribbled paper rather than a methodical, systematic diary which tells one very little?

The (swimming) slender groundhopper

Whilst loitering around ponds, as I do, this spring I have seen numerous slender groundhopper Tetrix subulata along the pond margins. I can’t help noticing that on my approach they purposefully leap into the water to avoid me. At first I thought they were accidentally doing this and tried to fish one or two out but then noticed that they swim very confidently underwater. Since then I have noticed them frequently leap towards the water and swim very happily downwards ‘to safety’ away from my tread. A strange defence adaptation for such a land-loving family of insects whose name suggests they are closely related to the ground as opposed to water!