Holiday Questions in Natural History

Last week I escaped to the Shropshire hills and blissfully allowed my brain to stop turning over matters concerning committee-work, exams, grants and other responsibilities past, present and future. Instead I have been exercising my limbs up and down the slopes of the Long Mynd and surrounding countryside and refreshing myself in local hostelries, albeit largely with substantial quantities of iced lime and soda to cool me down and replenish my liquid levels after hefty hot walks: the weather was generally kind and the countryside gorgeous and enticing me to walk further than I would have expected my stamina could take me.

The area was delightfully quiet with no major roads. Noise mainly seemed to come from the tractors busily cutting the hay and baling it (or whatever the correct term is for those cylinders tightly wrapped in black plastic; bales from my youth were rectangular), the mechanical growls sounding across the valleys. Gliders circling on the thermals above the Long Mynd also produced an eerie hum as they passed overhead (naively I had thought gliders were silent). But there were also the sounds of chattering swallows as they swooped around farm buildings, the frequent call of chiffchaffs from the hedgerows, the mew of buzzards above the fields and the incessant bleating of (nearly full-grown) lambs who’d temporarily lost their dams.

When indoors my reading matter was also pleasantly irrelevant to my normal daily round. But it seemed particularly appropriate to spend evenings enjoying Meadowland: The Private Life of an English Field by John Lewis-Stempel, describing a year on a Herefordshire working farm’s pastures and meadows, situated somewhere not very far south from where I was staying. His descriptions of the meadowlands of the title in the summer months absolutely chimed with the appearance of the fields across which we were walking. Resorting to a scythe (an instrument I dimly remember seeing once in use in my far-distant childhood) when his mechanical equipment for cutting failed, may seem extreme, but he was clearly very much at one with his fields and lingered on descriptions of the wildlife he found therein.

I can feel smug that, without binoculars or even particularly trying, I saw or heard 45 different species of birds (list appended below for the curious) during my walks, a figure I felt that compared extremely favourably with the 55 he listed seeing on or above his fields over an entire year. Nevertheless I also recognized that whereas, erstwhile twitcher that I am I may feel smug about my ornithological identification, my knowledge in just about every other sphere of wildlife is pathetic. The butterflies/moths that I saw were not the ones I recognize from my urban life. They seemed predominantly to come in various shades of brown – sometimes with a tad of orange – but whether a variety of argus, fritillary, brown or something completely different I cannot tell (there was also a splendid caterpillar crossing the Long Mynd trail that seemed to feel no need to avoid our boots).

Likewise I realised my knowledge of the life of trees was sadly lacking. Why, in the village of Norbury, was there a venerable yew located in the churchyard cited on a nearby helpful board as being 2700 years old and still going strong, yet the striking double avenue of beeches up nearby Linley Hill were likewise cited as dying off at a mere 300 years of age. What limits the lifetime of a tree (aside from beetle infestation or other disease or indeed a lightning strike)? Do trees simply die of ‘old age’ and if so why the differential factor of 9 between yew and beech? Can someone please enlighten me as my scientist’s mind is curious!

I was also struck by the birds I did not see, or saw only in tiny numbers. I saw a single curlew with beak delicately probing at a recently cut field of hay but not a single lapwing (aka peewit) which surely would previously have graced these fields in large numbers. I heard a solitary yellowhammer with its once-familiar call of ‘a little bit of bread but no cheese’ that I used to hear regularly even on Hampstead Heath. Skylarks were thin on the ground too although the meadow pipits seemed to be thriving. And in the hedgerows there were chiffchaffs a-plenty calling but of its close relative the willow warbler not a single cadence did I hear; this is a phenomenon I have noticed around Cambridge too.

The most magnificent spectacle was, however, of a bird that used to be all but extinct in the UK. 10 or 11 red kites circling was an amazing sight. These birds are huge and beautiful but they were all but hunted out of existence over many centuries. Recent reintroductions have seen them prosper: I believe they are now even breeding on the outskirts of Cambridge (although the nearest I have seen them is from the A1 near Peterborough). Nevertheless to see so many of them up close and personal is striking. These birds no doubt were once affected, like so many birds of prey sitting at the top of the food chain, by organochlorides such as DDT; now they are flourishing.

In contrast many of the once-common insect-eating birds are now being hit, according to a study published in Nature just this week (written up in the Guardian which was where I read about it whilst on holiday), by neonicotinoid insecticides, which have already been implicated in the drastic fall in bee numbers. Part at least of the decline of starlings (which I noticeably did not see during my week away), sparrows and swallows seems attributable to these chemicals. The decline in other species such as lapwing, skylarks and yellowhammers are probably due to changes in farming practice (and, by implication, EU subsidies) destroying their nests before their young are fledged.

So, as ever, when I go on holiday my mind does not switch off from scientific matters completely, it merely changes a gear or two. A previous trip to the seaside seemed to present more physical science challenges than this week of walking in Shropshire, but there are always questions to ask. On this occasion the frustration the unanswered questions provoked was made the worse by the complete absence of any internet access due to the poor reception on my mobile. Now I’m back in Cambridge perhaps I really should sit down and consider what determines the lifetimes of trees and the identification of the panoply of butterflies that flitted past my tired legs.

Birds seen or heard during the week:

Wood pigeon, song thrush, blue tit, great tit, long tailed tit, marsh tit, coal tit, greenfinch, goldfinch, chaffinch, linnet, redpoll, bullfinch, skylark, meadow pipit, greater spotted woodpecker, redstart, spotted flycatcher, dunnock, blackbird, house sparrow, nuthatch, chiffchaff, blackcap, yellowhammer, swallow, house martin, swift, red kite, buzzard, kestrel, carrion crow, rook, raven, jackdaw, magpie, jay, curlew, mallard, wren, robin, pheasant, wheatear, grey wagtail, pied wagtail.