The Thurlows

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Nature Notes 2019

June 2019: Conservation politics

I see that Chris Packham has raised the controversial question of whether we should cull deer to help protect nightingales.  What – do deer attack nightingales and kill them? No, not directly, of course. What’s true is that the deer population in Britain has exploded in recent years.  There are now an estimated two million deer at large in Britain’s countryside – the highest numbers for over a thousand years.  There are now no natural predators here like bears, wolves or lynx to keep them in check and the numbers of our native roe, red and fallow deer have exploded and have also have been augmented in recent years by various introduced species like muntjacs and Chinese water deer.   And all these deer are eating away the understory of trees and bushes in our woodlands on which nightingales and other songbirds crucially depend for cover. Nightingale numbers are in free-fall anyway.  We have already lost over 90% of the population from various causes and the deer may be finally pushing them over the edge.  Surely we couldn’t bear to lose this iconic species, that ‘singest of summer in full-throated ease’, as Keats put it?  On the other hand, could you look into Bambi’s soft brown eyes and pull that trigger yourself?  

Nature conservation presents us with many such dilemmas and choices.  We know that badgers and hedgehogs can’t coexist, for example.  They are both favourite characters in countless children’s books, but I’m afraid Mr Brock kills and eats Mrs Tiggy-Winkle whenever he can catch her.  Whose side do we take and why? We prefer red squirrels (Squirrel Nutkin) to the grey ones (aka ‘tree rats’)  – so much prettier and cuter.  The greys were introduced into Britain from North America in the 1800s and have progressively displaced all ‘our’ red ones by a combination of brute force and pox (‘oversized, oversexed and over here’ again).  So, should we perhaps re-introduce some lovely pine martens from Scotland to predate the greys, which the martens find easier to catch than the reds?  But, whoops, hang on – pine martens kill young chickens and pheasants too and take all manner of wild birds’ eggs, so perhaps they are best left up North? 

Introductions can go badly wrong anyway – just think of the disaster of taking rabbits to Australia with the First Fleet in 1788.  They bred – well, like rabbits – and caused untold damage to the environment and to crops.  Do you remember coypus?  This huge South American rodent was introduced into England to be farmed for its fur last century, but some were let into the wild and they started destroying the river banks and water systems and had to be expensively eradicated.  And are the Americans glad to have the two hundred million starlings that derive from the eighty pairs from England released in Central Park in 1890? 

How do we decide such questions anyway?  Is it a matter of sentimental human preferences, charisma, perceived beauty, economic interests, nationalism or what?  Someone should write a book about it …

 

Jeremy Mynott

Lavender Cottage

8 June 2019 

 

May 2019: Changing places

This month’s Nature Note comes from New York.  What?  Nature in New York, the ultimate concrete jungle? Well, yes, there are jungles within jungles even here.  I used to work in NY once and my local birdwatching patch there was Central Park, which is alive with wildlife of all kinds. This was a sentimental return visit.  Central Park is over two miles long by half a mile across, so about the same size as my local patch in Thurlow – and the two have more in common than you might think. 

Central Park was created in the 1860s by two landscape architects of genius, Olmsted (an American) and Vaux (an Englishman, who actually invented the term ‘landscape architect’).  The area had been a sort of swamp before then, ‘a pestilential spot’, said Olmsted, ‘where rank vegetation and miasmatic odours taint every breath of air’) and they proceeded to recreate it completely, according to their manifesto that ‘the Park throughout should be a single work of art’.  They employed some 3,000 labourers (mostly Irish) and shifted one billion cubic feet of earth.  They introduced lakes, hills, rocks, streams, meadows, gardens and woodlands, all designed to create a green sanctuary within the city.  They planned it with human visitors in mind, but it didn’t take long for the birds to find it as well, and for two main reasons.

First, NYC is right on the flyway for the thousands of birds migrating between their summer homes in New England and Canada and their winter quarters further south. Every spring, tired migrants gratefully pause to rest and refuel in Central Park, which from the air must seem like an oasis in a concrete desert.  Secondly, the Park offers a great range of habitats: lakes and streams for wildfowl and water-birds; woodland for all manner of American thrushes, warblers, tanagers and vireos; thickets for owls and catbirds; mature trees for woodpeckers, flickers and sapsuckers; vantage points for raptors; and even a few paved areas for urban refugees like starlings and house sparrows. Starlings were introduced to America when 40 pairs were released in Central Park in 1890, on the initiative of one Eugene Schieffelin, who had the absurd ambition of introducing to America all the 60 or so birds mentioned in Shakespeare. The starlings and the sparrows flourished, but the nightingale and most others failed (and what he did about the ostrich and the phoenix isn’t recorded…).

You can see 100 different species here in a day in the spring, well over 200 in the course of a year, which compares very well with the countryside round Thurlow.  The other thing I like is the familiarity.  I knew just where I would find American robins on the Great Lawn, palm warblers by Willow Rock and buffleheads in the corner of the Reservoir. There was even a rare bird in the Ramble, a yellow-breasted chat, in which the drug-pushers were taking a proprietorial interest (‘It’s over there, second bush on the left, and would you be wanting anything else, Sir?”).

 

Jeremy Mynott

Lavender Cottage

9 May 2019  

 

April 2019: Welcome migrants

April and May are the great months for travel in the natural world. For centuries people have used the comings and goings of birds as a sort of seasonal calendar.  As the Song of Solomon has it in the Old Testament, ‘For lo, the winter is past, the rain is over and gone.  The flowers appear on the earth; the time of the singing of birds is come, and the voice of the turtle is heard in our land’.  Well, the lovely ‘voice of the turtle’ (that is, the turtle dove) isn’t much heard in this land now, and the prophet would be lucky to find one in Thurlow this year.  I used to think of the turtle dove as the sound-track of summer, with that lovely purring song, but the numbers have declined so precipitously in recent years and we’ve lost over 95% of our turtle doves in a generation.  But the general point is true.  Bird migration has long been a source of wonder, particularly its regularity.  I’ve been recording the arrival dates of summer visitors like the chiffchaff, swallow, cuckoo and swift (usually in that order) for over three decades, and although the dates have been getting steadily earlier with climate change, I still look out for particular birds on particular days each spring and welcome them like old friends, with a mixture of familiarity and relief.  It’s a bit like those airport announcements, ‘The 12 April Swallows from Cape Town have just arrived on time at the Great Thurlow Barn’.

But it isn’t just birds that make these huge and hazardous journeys.  Lots of butterflies and other insects do, too.  Most of the red admirals and painted ladies we see here in the summer have migrated from the continent, sometimes in huge numbers.  I well remember the extraordinary summer day in 2009 when painted ladies poured in off the sea on the Suffolk coast in what seemed like a continuous stream for hours on end.  It’s estimated that over ten million of them crossed the channel into Britain that day and they were everywhere.  Some moths migrate, as well, and we are just learning some remarkable facts about how they manage it.  The Silver Y moths, for example, one of our common summer migrant moths, can choose exactly the right altitude at which to fly to catch the most favourable tail-winds and can even orient their tiny bodies in the best direction to compensate for cross-winds.  Incredibly, they can sometimes fly faster this way than migrating birds like warblers crossing at the same time.  Ladybirds have also been recorded migrating at great heights – sometimes as high as 1,100 metres.  And marmalade hoverflies (what a great name) arrive in their millions every summer, to perform a wonderful pest-control service in your gardens where their larvae consume literally trillions of aphids.  And they do it for free.

 

Jeremy Mynott

Lavender Cottage

18 April 2019 

 

 

March 2019: Connections

You know that BBC programme, Only Connect, where brainy panellists have to guess the unlikely connections between quite different words.  Well, here’s a free suggestion for a tricky question: what’s the connection between cows, beetles and partridges?  

Starting with cows, then. Cows have been blamed for a serious contribution to global warming through their massive emissions of methane gas. That comes from both ends, so to speak –belching and flatulence.  Apparently, a cow can produce some 50 gallons of methane a day, and since methane is over twenty times as powerful as the carbon emissions we hear so much about, and there are some 16 million cows in Britain, you can see (and often hear) the scale of the problem.  In New Zealand, which has much more livestock than we do, there was even talk a few years back of a ‘flatulence tax’ to help save the planet.  But I recently read a scientific article with the splendid title, ‘In praise of cowpats’, which makes a rather different point.  Cowpats feed a host of insects.  Masses of flies and beetles arrive within minutes of a fresh, glistening cowpat hitting the ground; these are followed by legions of others as the pat matures, decays and is eventually pulled underground by worms and dung beetles, so contributing to rich new plant growth. Each pat in open pasture produces some 1,000 developing insects this way – so with an average output of six pats a day that’s 6,000 insects a day or over 2 million a year.

And we now know how crucial insects are to the whole chain of animal and plant life.  They pollinate plants, provide food for birds and mammals, and are crucial to human agriculture and food supplies.  It’s been estimated that if all the world’s insects were ever to disappear humanity would only last a few months and the earth would eventually become a vast compost heap, supporting only a gigantic blooming of fungi.  But we also know that insects are themselves under great threat. A recent study in Germany revealed a 75% decline in insects since 1989 – and that was in German Nature Reserves! This is largely a consequence not of climate change but of habitat loss and the pesticides with which we drench the land; and that in turn explains why many farmland birds have declined so sharply. 

Which brings me to the third element in my quiz question: the grey partridge, whose numbers in Britain have declined by a staggering 90% in a single generation.  Wild grey partridges were once common in the East Anglian countryside, but the ones you see around here now tend to be released birds, though there are plenty of red-legged partridges. Now – I’m getting to it at last – the scientific name of the grey partridge is perdix, so called because the whirring sound of a covey of partridge taking flight was thought similar to the natural human process described by the ancient Greek verb perdomaimeaning ‘to break wind’. So there you have it.  Not many people know that. 

 

Jeremy Mynott

16 March 2019 

 

 

February 2019: Changing diets

Did you make any New Year resolutions about diet?  Still keeping to them? Thought not, so take a tip from wildlife.  Some species have remarkable ways of changing their diets to suit the season – and in particular to get them through the winter.  As the days get darker and colder in autumn insects become much scarcer, so blackbirds, blue tits, starlings and other insect-eaters go vegan and switch to alternative sources of energy like seeds, nuts and berries.  A good example for us, if you believe all those diet books.  

But other species take more extreme measures you’re unlikely to want to imitate.  There’s a bird called a bearded tit, for example – a real misnomer, since (a) it isn’t bearded (it has a nice black moustache) and (b) it’s unrelated to the blue tits and great tits you see on your bird-table.  Bearded tits breed in large reed-beds like those at Minsmere and Walberswick, but they range more widely in winter.  I’ve seen them a few times on the Suffolk coast, feeding – rather incongruously – at the roadsides.  What they were doing was swallowing gravel and tiny stones, which they store in their crops to help them crush and digest the seeds they’d been harvesting from bulrush heads.  It’s a sort of DIY grinding machine. Their waists and weights expand accordingly over the winter period.

Shrews go even further.  They can’t hibernate and switch off, but need to feed continuously and therefore have to take quite drastic measures.  The organ that absorbs most of their energy budget is the brain, so they re-absorb that and literally shrink their heads to reallocate resources. The scientific name of this strategy is known as Dehnel’s phenomenon. As a solution to a critical problem it’s a no-brainer, you might say. Come spring, if the shrews have survived, they just grow their brains again. Don’t try this at home, but ‘going to see a shrink’ may take on a whole new meaning for you.

The most extreme solution of all is practised by various moths. The December moth, for example, is so called because it’s one of the few flying at that time of year. But in its earlier form it fattens itself up as a caterpillar, over-indulging as if it’s Christmas lunch every day. And when it later emerges as a plump moth from its chrysalis stage into chilly winter, with no nectar or sap to feed on, it just lives off its accumulated fat … and then dies.  Adults are physically incapable of feeding, so that’s it.  No Plan B and not much of a life, you might think.  But it does at least get to mate and deposit some eggs to ensure the next generation.  Whether as a moth it remembers its happy childhood seems unlikely, but that’s metamorphosis for you.

I think humans tend to put on a little weight in the winter as well – to cheer themselves up and add a little insulation, but you can always revive your resolution and change your diet again in the spring.  Life goes on.

 

Jeremy Mynott

Lavender Cottage

12 February 2019

 

January 2019: Berried alive

HawthornI’ve never seen the hawthorn bushes so laden with berries as this year.  If you walk along the lanes you’ll see the lines of ancient hawthorns stippled in scarlet like a pointilliste painting.  The haw of the hawthorn is the red oval cup, technically called a pome (not to be confused with the acronym P.O.M.E.  ‘Prisoner of Mother England’, originally used of inmates deported to Australia – just in case you’re doing any pub quizzes).  The hawthorn belongs, somewhat surprisingly, to the large rose family, which also includes rowan, blackthorn, damson, apple and cherry, as well of course the rose itself, all of which have similar pomes encasing their seeds.  The word ‘haw’ comes from the old-English haga-berige, meaning hedge-berry, and the trees are an ancient part of our landscapes.  There are more references to hawthorns in the Anglo-Saxon charters than to any other tree and hawthorns are also the trees most often encoded in English place-names, like Hawstead.  But it wasn’t until the parliamentary Enclosures of the 18thand 19thcenturies, when some 200,000 miles of these ‘quick-thorns’ were planted, that they marked the rectilineal geometry of our field boundaries in such abundance.  

In spring, of course, this is the May tree (the only tree that shares its name with a month), and last spring was notable for the billowing clouds of white blossom that graced our hedgerows everywhere.  I met a lady on a walk in Thurlow recently who asked me if I believed the old country saying that a heavy berry crop presages a hard winter. In fact, I fancy that the causation works the other way around, and that the foaming bridal display in spring is now being realised in this wonderful, winter fruitfulness.  I doubt the hawthorn can make long-range weather forecasts any better than the BBC can … 

Any tree as ancient and charismatic as the hawthorn is bound to present itself today not just as a biological species but also as a cultural icon, trailing a comet’s tail of myth, fable and folklore.  The hawthorn’s red berries, like those of the holly, speak of dark rites involving blood and sacrifice. But they can be positive omens, too: Joseph of Arimathea, leaving Jerusalem after the crucifixion, is supposed to have travelled to Britain and struck his staff into the ground at Glastonbury, whence it burst into a sacred thorn tree that has for centuries flowered in the nativity season; and every Christmas a sprig from its descendants is still sent to the Queen as a symbol of renewal.  And these same berries are providing a rich larder for all the winter thrushes – redwings, fieldfares and blackbirds – that have migrated here from northern Europe to escape the hard weather.  Let’s hope these little beasties from the East don’t bring it with them this year.

 

Jeremy Mynott
Lavender Cottage

 

 

 

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