Wednesday, 2 October 2013

Nature Notes 2009


Frozen Orchard Pools
Today I went to Orchard Pools, completely and deeply frozen over so I could walk and slide right across them. There's a great and illicit pleasure in WALKING on water - though I am very cautious in using both  foot, ear and eye to test conditions, thumping the ice constantly and retreating immediately where it gives that 'Ice Road Truckers' ominous creak!
Here are three pictures I took (the whiteness is frost on the ice surface):
- One of a young swan on the ice.
- One of small pairs of paw prints that crossed the ice extensively and I also saw on a frozen ditch going in to Severn Beach. I thought it might be a fox, but maybe just a cat? Print pairs implied a dog rather than cat trot?
- Ice marks where a pair of ducks have come in to land and then pattered about.

Reporting unusual finds
A member commented that the Bristol Wildlife group's messages seemed to be more about reporting 'unusual' finds than everyday observations. This got me thinking: what IS the ‘unusual’? I thought: I’ve only been birdwatching and a member of this group for just over 4 years. In that time I have reported loads of things that I found beautiful, or amusing, or interesting, but I didn’t necessarily think they would be unusual for more experienced birdwatchers - mostly rather the opposite, as they were often just little things. However I have since realised that these little events actually very rarely repeat themselves and may even be unique for me. And that makes me think how very rich nature is, how varied are the responses of living (and inorganic!) things, and that the oddest little thing may actually be genuinely unusual!

Winter entertainment - Big Bling
Well it's not EXACTLY Bristol or EXACTLY wildlife (unless you count our crystalline cousins), but I thought this (found while doing some geological research) was pretty amazing and might brighten up the long winter days:
'Scientific evidence indicates that white dwarf stars have a core of crystallized carbon and oxygen nuclei. The largest of these found in the universe so far, BPM 37093, is located 50 light years away in the constellation Centaurus. A news release from the Harvard- Smithsonian Center for Astrophysics described the 2,500 mile-wide stellar core as a diamond. It is estimated to be ten billion trillion trillion carats, more or less. It was referred to as Lucy, after the Beatles song "Lucy in the Sky With Diamonds".' (from Wikipedia)

Back & front
There is the most striking division in my road (and presumably in many others) between the birds you will basically find only in the front, only in the back, or only on the roofs. I think the only birds comfortable with all three environments round our way are the sparrows. Otherwise we see pied wagtails on road and pavements out front, tits and finches in the back gardens, gulls and corvids on roofs, and starlings, magpies and pigeons on roofs and backs...
What brought about these musings was the snow, which is forcing birds who don't generally like to come down to food put out in the back garden, to venture there - gulls and corvids in particular; I also saw my first ever pied wagtails scouting conditions there. The snow also creates a wonderful ephemeral record of unseen goings-on like the brush of wings where a cautious crow wouldn't even land but scooped up some bread in flight...
I'm loving it! The peace and serenity! The fun! The disruption of normal life!

Snuff Mills
Moorhen, by Christine Matthews
Along the River Frome at Snuff Mills yesterday, I watched a moorhen close up in bright light and saw an effect I'd not appreciated before: the plumage above the white 'plimsoll line' was a smooth beautiful subtle bronze colour. 
Walking back by riverside trees close to the pavement, a long tailed tit and a goldcrest were feeding within a few feet of me. They both methodically moved up and down branches searching for food, both effortlessly moving upsidedown as required. However while the tit's tiny weight was sufficient to rock the twigs, the goldcrest's wasn't - thus giving a convincing impression of moving in a zero-gravity environment!

Psychotropic blackbird...
Had I unwittingly ingested a psychotropic substance?... Last night in my dormer room I heard strange birdsong. I opened my rear window onto a peculiar experience... it was almost dark and a huge full moon hung low in the sky. A blackbird (or some changeling thereof) was perched in the top of next door's tall pine tree and singing in a way I have never heard before – not only strange and sometimes quite violent song, but occasional absolute shrieks and gibbers. When it quitened down, three other blackbirds lower down along the backs of the houses opposite, could be heard giving alarm calls in sequence, and I could hear just one 'orthodox' bit of mellifluous singing... What WAS going on? Does the full moon affect birds?

Inspired by previous posting about a proposed Severn Barrage and the damage we do to our environment, I recently had this strange thought: if all humans just stopped propogating and didn't have any more children as from today (not such an outrageous idea if you think of people doing that one by one, rather than all x billion of us!)- then we'd all be gone in 100 years! So simple! (Not that I am advocating the complete elimination of the human race - it's just a thought experiment) But of course nature is no fool, and made the sex drive strong enough to overcome almost everything... especially rational thought...

Flight Fuel
I thought members might enjoy this extract from a book on biological clocks. Regarding bird migration it says, ‘A typical blackpoll warbler at the end of its breeding season weighs about 11 grams. In preparing for its transatlantic trek, it may accumulate enough fat reserves to increase its body wight to 21 grams. Given an in-flight fat consumption rate of 0.6 per cent of its body weight per hour, the bird then has enough added fuel for approx 90 hours of flight for a journey that, under fair conditions, requires about 80-90 hours. The 14 grams of fat in a single Snickers bar would provide one and a half times the amount of energy necessary for the blackpoll warbler’s flight from New England to South America. If the warbler were burning petrol instead of reserves of body fat, it would be getting 720,000 miles to the gallon.’ (from ‘Rhythms of Life’ by R Foster & L Kreitzman) Now that’s what I call energy efficient!

A friend has a wooden bird table in her garden, on a tall pedestal leg with a little roof over it. Here's a ludicrous sight: her cat climbed up and fitted itself onto the table under the roof (- only just - ), possibly thinking birds might still conveniently fly down and into her waiting claws?

Aust Wharf
At Aust Wharf today: on the foreshore were curlews, shelducks,
oystercatchers and mallards. On the saltmarsh, many skylarks were singing like mad and springing up from underfoot, along with  pippits and a  kestrel hunting over. A shallow muddy creek was covered with brackish water crowfoot, a lovely and unusual plant with five-petalled white flowers with a yellow base, and fresh green-coloured leaves that combined both a ferny foliage and trefoil leaves. The mud walls of a deeper creek shone with an unnatural brilliance in the sun: gooey, juicy, gelatinous, oleagenous...

Bridgewater Bay
I just spent three days car-camping between Steart and Kilve on Bridgewater Bay (the Bristol Channel below the River Parrett). (I wondered how ‘Steart’ was pronounced -  ‘Is that Steart as in heart, or Steart as in heard, or Steart as in steer?’ - it’s the last one.)
Four miles up the Parrett is Combwich, a lovely little cul-de-sac town on the southside  of the estuary, where I parked on a gravel access road along the river. I was recovering from my 60th birthday celebrations and
by Des Bowring
lay in the back of my car with the boot open through the afternoon,  watching a flurry of bird activity. There were swallows in abundance, sitting on the wires above and dropping almost by my feet to pick up nesting materials; they flew so low and close that a flick of a wing would have brought them into the car. Birds seemed to have decided it was wash day - the puddles up the road alternated, with sparrows splashing in one and starlings in the next. On the church tower was a an owl sculpture of size and shape of eagle owl - but I had to check it out with bins, cos nowadays it could be the real thing! Alders looked pretty with dainty new pale green catkins developing amongst last year’s woody ones.
Just in from the sea edge, marsh meadows were full of larks and pippits and I saw three hares early in the morning. I walked to Hinkley Point where the route was a riot of small birds: there were lengths where every other shrub had a whitethroat in it on one side, and every few yards had a reed warbler singing in the reeds on the other. I heard two cuckoos about 4 miles apart - one near Steart and one near Hinkley.
Brown hare, by David Baird
It was interesting to experience how this area is the very last bit of the Somerset levels, and from now on south of Hinckley the land rises to the Quantocks and onwards. It feels very old: there are still old stone anti-flood walls running parallel with the newer levees, with raised gate openings reached by grass ramps.
At Kilve I walked north along the coast path to Hinkley from the other direction, seeing dramatic exposures of Jurassic limestone platforms at sea level, cracked into extraordinarily regular patterns. Though I must have seen shelduck fly before, was the first time I really noticed how dramatically beautiful they are in flight with the strong black and white on show; I also saw two more hares.
I stopped on the long limestone pebble beach past Lilstock. If anyone wants a laugh, look up ‘Lilstock Beach Hut’ - this is where a small group of enthusiasts cleared all the beach litter and built a sort of crazy theme park from the detritus at the back of the middle of the beach, including a habitable beach shack complete with benches padded with scrunched-up fishing net and a working stove. It’s obviously a work in progress with winter storms taking a regular toll as well as bringing new material, but equally a work of love!

Today I came the closest to a swift that I've been: on a small road of 2-storey terrace houses in Bishopston, a swift swooped down below roof level, shot up and inspected an under-eaves site, perching on the wall, and then away - it did this twice. (The under-eaves were old-fashioned, no soffit, spaces open into the roof itself) It reminded me of a shark - dense, dark, sleek, powerful - and swift.

Bad joke
Apropos of nothing except watching a video of happy badgers enjoying their home,
on Springwatch just now: 'Badgers at home - the Joy of Setts'. Apologies..

North Cornwall
I have just been cliff walking south of Newquay, Cornwall. The wonders and things of interest I have seen include:
- A host of newly-fledged birds, many tottering around in their family groups or acting too friendly with humans, including robins, linnets, pippits and crows. I watched a young gull ridge-soar along the cliffs with a group of adults, wobbling slightly in comparison with the adults’ perfect lines - which made me think once more about the big learning curve youngsters have, even allowing for instinct.
- The most exquisite varied and brilliantly-coloured vegetation. I have done my best to name some of them though this will not all be accurate: thrift, sea campion, wild carrot, orchids from pure white to deep purple, stonecrop (many cushions so completely covered with flowers you couldn’t see a single leaf), kidney vetch, bloody cranes bill, rockrose, scarlet pimpernel, speedwell, centaury, thyme, yellow rattle, plantain, curled dock (huge flopping red ‘flower’ spikes), scabious (both the bigger, paler one and the tiny more intensely
Sheeps-bit scabious
by Christian Fischer
blue one (Darrel: latter probably sheeps-bit)), ox-eye daisy, hawkweeds, soft rush, honeysuckle, gorse, briar rose. Also tiny brilliant blue, and white flowers in the short turf that I can’t identify. (Darrel: possibly sea milkwort) There were spreading acres of fresh, bossomy heather of intense, almost poisonous greens and purples, accented with tiny touches of yellow and white from other flowers; in one area amongst mining tailings of sombre mineral hues, this was mixed with dead heather of a leaden colour, and big cushions of a verdigris-coloured succulent. One cliffpath wall was covered with ivy through which was growing heather, gorse, roses and honeysuckle; sometimes the honeysuckle perfume became so strong it was too much - like walking into a big bar of soap. Looking into the hearts of the hawkweed was like looking at freshly-glowing suns and I had floral competitions: most intense magenta - bloody cranes bill or heather? Most brilliant yellow - hawkweed, gorse, vetch or buttercup? Inland I have never seen such valerian: walls were rampant with huge growths in the full three colours of red, pink and white.
- I saw many kestrels and buzzards but no peregrines, though this must be prime territory. However I found a freshly dead pigeon on the path, upper parts completely torn away which I would think was a peregrine hit. It had ringed legs with a ‘Please phone - tel no.’ - was this a racing pigeon?
Razorbills, by Steve Garvie
- My most fantastic birdy surprise was on a very lonely stretch a mile or so south of Porthtowan (Gullyn rock) facing a deep cleft with 200’ sheer cliffs. There was a small razorbill colony - a bird I haven’t seen or expected to see. They are so wonderful and endearing, like our very own penguins, and cute - tho I realise at 16” and with those beaks I might revise that at closer quarters! They perched about 150’ up, hurtled off towards the sea and then came hurtling back again, landing in that endearing puffin-like way with big flipper feet stuck forward. Oh the insouciance of being a seabird and prancing about on a tiny ledge miles above the foaming sea and deadly rocks...
- There were other birds in numbers along the paths, including pippits, whitethroats and stonechats, and one superbly plumaged male wheatear. Two cuckoos called a couple of miles apart at St Agnes Head. 
- One thing I found a great mystery on my Cornish trip was this: the upper last few feet of many vertigenous sea cliffs were topped with sandy soil, and had rabbit-sized burrow openings actually emerging straight over the void. As I cannot believe that rabbits were running out to fall to their doom, what were these for and were they built by rabbits or some other creature?
- A little geological marvel that can stand with any natural wonder of the world is the Holy Well in a cave on
Holywell Beach, by Mike Hancock
Holywell beach. At lowish tide, walk north up the beach away from Holywell village, pass the more impressive-looking high caves and look for a low arched cave near the end. The well is inside just on the left, where a tiny flow of water from the roof has created a series of perfect little calcite pools, one flowing down from the next in exquisite formation as though created by Nature’s own Chelsea Garden designer. But more: you can see in the roof strong ribs of a deep rose mineral, and as this has separated from the calcite it has built the pool edges out of tiny scales of white rimmed with pink, so each ones appears to have been formed from some wonderful fish like a magic carp. I guarantee you’ll love it!
- And finally: this is prime historical tin-mining area, and I think it’s worth anyone’s interest to note that: ‘Artefacts found on tin sites and identified by archaeologists indicate that the tin industry was established by the Early bronze Age (2100-1500 BC) and was widespread by the Early bronze Age (1500-800 BC). Finds in all the main tin-producing localities between Dartmoor and Land’s End show that from as early as 1500 BC the extraction of tin has probably continued without serious interruption until the present day. Historical references support this. They show a well established and fairly sophisticated tin trade between Cornwall and the Mediterranean by the 4th century BC. There is little evidence that any of the great events of history - such as the invasion by the Romans and their withdrawal 350 years later - did any more than temporarily disturb that international trade.’ Ancient historians reported that ‘the Cornish were friendly and civilised due to contact with foreign merchants’! (from J A Buckley’s ‘The Cornish Mining Industry’) The fundamental point being that ancient bronze is made of tin and copper (a hard alloy, made from two softer ones that can be smelted at temperatures technically available at those times - iron requires a much more demanding higher temperature), and that tin internationally was a rare metal and Cornwall was one of the greatest producers in the world. Without Cornwall and the Cornish miners the great Bronze Age civilisations would have struggled!

On Beauty
On Springwatch last night, photographer John Aitchison spoke most movingly and eloquently about what insires him, particularly just looking for beauty - in the simplest things - a stretch of mud, an outline - often created by the play of light. It resonated most deeply with me, and what moves me when I go out walking, and the deep pleasure I get in trying to recreate something in words (often to post to this group) - to try and pass that experience on and move someone else in turn, as well as fix it for myself. Now that I have taken up drawing again I'm also trying to fix ephemeral beauty on paper, but that's a lot more difficult I find...

Ham Green
Female Emporer dragonfly
by Stavros1, en.wikipedia
It was so hot yesterday, I went to my personal bit of heaven - the upper Ham Green pool - for a swim in the evening. It was very beautiful and abundant with birds, dragonflies, fish, water lilies etc, and the huge trees soughed in the warm wind. A moorhen was taking a thorough bath on the far edge of the water, plunging and preening: I noticed for the first time that they have a fancy stripe of red and yellow garter where their legs meet their body, matching their beaks. Two youngsters were imitating the adult with their own plunges and preens, shaking out their small wings, their beaks just turning rosy; one lifted a huge gangly foot to scratch its neck.One of those massive dragonflies (Female Emporor) with a sort of bulldozer body, green, was laying eggs in the water plants. A tall scots pine on the opposite bank had a flaw running up the trunk with woodpecker holes drilled at even intervals up it, and a new one shows fresh orange wood.

by Des Bowring
A young starling and sparrow were happily sharing a crust on the lawn yesterday. I suppose like everything else, it takes practice to learn to become bossy and competetive...

Migration feats
Gull expert Pete Rock wrote, 'So, the absolute world speed record for Lesser Black-backed Gulls has been smashed! Have a look at this paper and marvel at how one bird made the 900+  km from somewhere in Wiltshire to a landfill in Asturias (N.Spain) in 20  hours!'
I replied, 'Hi Pete, are you serious that this gull averaged 45kph (approx 30mph) continuously over 20 hours? Are feats approaching this common? I wouldn't approach such an average in a car as I would need to spend a lot of that resting, eating and sleeping.'
Another member replied, 'Hi Lois, If you want a really staggering bird endurance stat see this month's British Birds. I knew Bar-tailed Godwits were serious long-distance travellers, but one has been  satellite-tracked flying non-stop from Alaska to New Zealand - 11680 km in just over 8 days! That works out at 1442km per day, or 60kph for over 194 hours! Apparently stopping off on the way would be energetically disadvantageous because of the extra distances required to divert to feeding areas, the uncertainty that good feeding would be available, and reversal of physiological changes such as atrophy of the gut which prepare them for this truly marathon flight.'
Pete added, 'I am sure that endurance of individuals of various species is more common than has so far been demonstrated. Back in the days when science was a bit hit and miss, I remember reading about a Manx Shearwater was taken from its burrow on Skokholm and dumped somewhere off Brazil just to see if it came back (yes, hit and miss science.). If I recall correctly, it was back in its burrow 4 (or maybe 5) days later. All good stuff. But back to gulls! Heike Schmaljohann was more than 500 km into the Sahara in Mauritania with a portable radar and found Lesser Black-backed Gulls moving at speed and at great height. In order to cross Sahara (stopping, it's suggested, would be folly) a non-stop flight would take a minimum of 36 hours. Pity those birds didn't have satellite transponders... And, on the subject of speed, I did some work for Gloucestershire Airport on their gull 'problem' a few years ago. Basically, something in excess of 16,000 gulls fly over the airport or its approaches every day during the spring mainly because the airport sits right in the middle of a flight corridor. The airport radar showed clusters of gulls moving at 55 knots - this is just over 63 mph, or 102 kph. In the Severn Estuary Region something like 84% of large gulls are urban gulls. The notion put to me by the Orfordness gull ringers when I found fewer of my birds than theirs in
Morocco, but many more of mine than theirs in Portugal was that my birds are lazy, fat bastards, either unable or unwilling (because of the easy lives they lead in town) to fly as far as Morocco They may be able to fly at over 100 kph, but for how long is the question. Was the Dutch bird really a world record-holder? Time will tell.'

Sweet chestnuts
by Colin Smith
Went collecting sweet chestnuts today, at Cleeve and Ashton Court. I have noted with interest that they apparently use the same breeding tactics as owls and other birds of prey. Generally within each prickly husk are three nuts, of which one is always bigger than two generally undeveloped or less developed nuts. I expect in sunnier climes like Corsica there is the wherewithal for all nuts to develop more fully, but here at the limit of their terrain they use the 'sacrificial lesser nuts' strategy, as the birds do with their older, bigger and younger, smaller nestlings.
A member replied, 'I believe the Autumnwatch team have film of the larger nut viciously attacking and absorbing its smaller siblings but feel its too sensitive to broadcast. However now the programme goes out after the watershed we live in hope!'

Starling strength
There was a tame starling on Autumnwatch, demonstrating its ability to prise a container lid off by inserting its beak point and then opening the beak - apparently they search for insects in grass by inserting the beak and then pushing to create a hole. This implies a strength of local muscle that seems incredible and for which I can simply think of no equivalent, animal or mechanical. Of course it's the opposite of crocodiles with their terrific jaw grip but feeble ability to reopen the jaw. The only thing I can think of is the tool firemen use to force open vehicle doors to get to people trapped within, but I don't know how those work. But imagine trying to force a hole in earth by inserting your fingers and then pushing outwards - simply wouldn't work! You'd need to insert a lever and push and pull on it using bigger muscle groups and some body weight force.

Yesterday I drove to Portishead to enjoy the storm, and also to enjoy watching birds do their insouciant 'I'm totally in control here' as they were hurtled across the sky like Exocet missiles! However even the best actors can't look anything but hilarious as they are blown along sideways, little wings outstretched in the wrong direction...
In counterpoint, the small birds in my local Filton park - tits and sparrows – looked remarkably comfortable and snug as they hopped about in the shelter of the shrubbery as the gale roared beyond. (And I noticed that Filton had one of the higher local wind gusts, reported at 50mph, though that was half the speeds recorded on the south coast...)

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