The bees burrow and completely disappear inside the tubular orange flowers.
These two shots show the pollen baskets:
You may have seen swans performing various synchronised movements or ‘dances’ together on the water at mating time.
The pre-copulatory rituals extend to preening, and although we’re out of the breeding season, this local pair I snapped this afternoon are clearly keeping in practice. Their synchronised stink-eye, reserved for loose dogs and over-eager photographers, is pretty impressive too.
Tonight I joined the 2011 Darwin Lecture, with Sir David Attenborough speaking on ‘Alfred Russel Wallace and the Birds of Paradise’, organised and hosted by the Royal Society of Medicine in association with the Linnean Society of London.
Fresh back from a trip to Borneo – no less, the spritely 85-year-old was introduced by Professor Parveen Kumar, President of the Royal Society of Medicine, and Dr Vaughan Southgate, President of the Linnean Society.
His account of Wallace’s ocean voyage to the Malay Archipelago and pioneering observations of that unique group of theatrical show-offs: the Birds-of-paradise, made for an informative and fun evening – all the merrier thanks to a generous ration of film clips showing the birds’ unlikely courtship rituals.
But the real take-home for me was Attenborough’s poignant re-telling of the Wallace-Darwin story: How the two independently arrived at that world-changing idea for the origin of species – natural selection – whereby only the better-adapted offspring of animals survive and pass on their qualities to a new generation.
Darwin had for years been working on his own version of natural selection from the comfortable surroundings of his home Down House, but had held back from publishing.
Then in 1858, Darwin receives a letter from Wallace, incapacitated with Malaria and holed-up in a shack on the Mollucas Islands of the Malay Archipelago. In it, he asks Darwin for an opinion on some ideas he’s had on the introduction of new species: ideas very similar to Darwin’s own.
Wallace’s communication is a bombshell. Yet for Darwin, the fear Wallace might publish first, pipping him at the post, is nothing compared to his horror of being branded a thief. So, after consultation with his scientific confidants, including Joseph Hooker but necessarily excluding the remote Wallace – Darwin’s camp decide a joint announcement of their common idea should be made at the Linnean Society in London, in the form of two short essays comprising Wallace’s note and a summary of Darwin’s work.
All goes to plan at the Linnean, and in due course Darwin publishes the full text of the ‘Origin of Species’ – with all the turbulent aftermath that comes with it. Wallace is comfortable with events, and pleased by the new associations he sees himself making in Darwin’s circle. He remains abroad, observing his beloved Birds-of-paradise .
Darwin, Attenborough said, made known his view that Wallace was capable – had he enjoyed Darwin’s own means – of producing the ‘Origin’ himself. Wallace on the other hand was more than grateful that the painstaking task of collation, supporting work, and documentation demanded of the masterwork had fallen to Darwin. In the lingo of the day, they’d reached a gentlemanly solution with no ill feelings all round.
Wallace produced much original work based on his observations of bird populations in the Malay Archipelago, which he captured in his book of the same name (The Malay Archipelago). Specifically, he identified the so-called ‘Wallace-Line‘ that runs between the islands of Bali and Lombok, separating two geographic regions whose animals Wallace found to be distinct and associated with either Australian or Asian origins. What he’d observed, without recognising it as such, was a product of moving land masses – or plate tectonics.
David Attenborough talks about his fascination with birds of paradise (Nature Video)
Meet the new arrivals. At a pool close to where I live in the south of England, I’ve been following the progress of these cygnets since their birth five weeks ago; the picture and the video were taken about a week after hatching.
The same breeding pair has built a nest in the same spot for the last four years: sometimes they get lucky – othertimes it looks like they go through the motions – or maybe the youngsters get dispatched by predators before I see them.
And for sure, it’s not all sweetness and light. Since I shot the video, one of the cygnets has developed a problem with its neck.
Swans , and particularly cygnets in their first year, are vulnerable to a host of threats: from natural predators like herons, crows, magpies and foxes;
to a bunch of man-made hazards including: being shot at, getting caught up with fishing tackle, lead poisoning, being attacked by pet dogs, crashing into electricity pylons, and getting run down by cars. Even well-meaning but misguided feeding can be injurious – mouldy bread is poisonous to swans.
When I visited the brood on 30th May, when the cygnets were about three weeks old, I noticed one of their number struggling to keep its head up. That might be caused by an injury, but it’s also a known symptom of lead poisoning.
As Doreen Graham of the Scottish Society for the Protection of Animals said in this 2007 BBC report : “Lead poisoning is quite easy to identify in a swan because they cannot lift their heads and their heads are resting on their backs”. There was a particularly bad spate of lead poisoning during the 1960s, although since then, with a ban on lead fishing weights, or sinkers, the Royal Society for the Protection of Birds (RSPB) believes the problem has diminished.
Lead shotgun pellets are the other likely culprit. There are bans or restrictions on the use of lead shot throughout the UK, with detail variations across the devolved constituencies; but there’s always the danger of legacy poisoning from old pellets lying in the reeds or on the pool bed.
All swans rest their heads and necks at times – it’s how they rest and sleep; but this one’s doing it most of the time, standing out from the group:
Fast forward to 8th June, when the cygnets are a month old, and at first sight there’s an improvement: it’s all heads-up in this convoy. But on closer inspection, number 4 from the left isn’t quite right:
and in this pre-roost preening session, there’s clearly still a problem:
And they settle for the night:
For now, the afflicted cygnet appears to be growing at a normal rate and, despite some earlier sniping by siblings, appears to be accepted by the group. I’ll be keeping an eye on this family over the coming weeks and update the blog with any developments.
UPDATE 8 July
Happy ending. Here’s the whole crew on 19th June – 11 days after the pics above. All six cygnets holding their heads up high. I’ve only just got round to updating, but if they’ve got this far they’re probably going to make the distance. Whatever was wrong with the afflicted cygnet seems to have worked itself through/out. (Not that these guys aren’t still in a warzone.)
Lead gunshot ‘poisoning UK birds’ (BBC News October 2012)
3. North West Swan Study (northwestswanstudy.org.uk)
4. The Threats to Wildlife from Pollution (Conservation Issues UK)
The Royal Society for the Protection of birds (RSPB) says: “the normal clutch size for mallard is 12 eggs, laid at one to two day intervals.”
Which makes the mother of this 16 strong brood paddling past our appartment yesterday something of a dynamic duck.
I’ve heard the record is 21 – so she still has a way to go. Impressive stuff all the same!
Through a combination of photography and a creeping fascination with avian behaviour and taxonomy (thanks to my wife giving me Colin Tudge’s The Secret Life of Birds for my birthday) I think I’m turning into some sort of accidental ornithologist. Point being, you can expect the occasional photo-flavoured birdy post; and today – it’s woodpeckers!
The female Eurasian Green Woodpecker (Picus viridis) above is one of the three most common woodpeckers found in the UK .
Photographically, woodpeckers are a challenge. The whole family is jumpy, taking off as a matter of principle at the sniff of a threat. So, considering I was sneaking up with no hide, I’m pleased how these turned out. Here are a few more of the male/female pair and a juvenile. You can tell the male by the red flash under his eye (click thumbnail to open slideshow):
And this male Great Spotted Woodpecker (Dendrocopos major)was snapped only a few days ago (click thumbnail to open slideshow):
Globally, there are 218 species4 in the Picidae family to which woodpeckers belong, living in every country with trees except for Australia and New Zealand.
Here are two more I snapped in California. The first set shows an Acorn Woodpecker Melanenpes formicivorus and the Ladder-backed Woodpecker Picoides scalaris (click thumbnail to open slideshow):
Here’s a video of a female Ladder-back hunting for bugs:
Acorn Woodpeckers are expert at turning trees into communal larders or caches. Pecking thousands of small pits in a single tree, they’ll place an acorn in each one – ready for harder times.
This set, again taken in California, is of a female Williamson’s Sapsucker – a member of the family specialising in eating the sap out of small wells drilled into the bark of pine trees:
Woodpeckers are a wonderful showcase for evolutionary adaptation.
Sharp claws set on toes laid out in the zygodactylous pattern – two toes facing forward, two back – are ideal for tree climbing. (Parrots and cuckoos are set up similarly, and elsewhere in the animal kingdom – Chameleons.)
Then there’s the way they hold themselves on the tree trunk.
Like rock climbers and photographers favour three points of contact for security and stability, woodpeckers have evolved a stiff tail to brace against the tree trunk and make a sturdy triangle with their splayed legs. The Sapsucker below demonstrates nicely; you can see her two tail quills bending under the pressure.
Having formed this miniaturised drilling platform, woodpeckers set-to doing their thing, which for a Ladder-backed woodpecker is banging its beak into bark and wood at up to 28 times a second, repeating the act several hundred times a day1.
The aim is to locate and consume insects and sap from under tree bark, a task for which their long, barbed tongue is well suited. But as this Great Spotted demonstrates, the birds are not above pecking the ground if there are bugs and termites to be had.
As hole-dwellers, woodpeckers also peck to hollow out a nest – a process that can take up to a month and involve the removal of tens of thousands of wood chips4.
For me, the woodpeckers’ most impressive adaptation is the multi-element shock absorber system that’s developed in and around its skull to prevent brain damage from all that bashing.
The full complexity of the system has only recently come to light. X-rays of a woodpecker’s head showed that the massive deceleration occuring at beak strike is cushioned and spread out thanks to elasticity in the beak, a spongy area of bone at the front of the skull, and a further special structure – the Hyoid – that directs pressure from the rear of the birds tongue around the back of its head1.
Well that’s a wrap on woodpeckers for the moment. Next phase is to try and catch these guys on HD video; they’re doing some great little courting dances this time of year. Reaches for camouflage gear….
References and further reading
1) A mechanical analysis of woodpecker drumming and its application to shock-absorbing systems. Sang-Hee Yoon and Sungmin Park 2011 Bioinspir. Biomim. 6 016003 IOP Publishing doi: 10.1088/1748-3182/6/1/016003
2) Digital Morphology. (Images at: http://digimorph.org/specimens/Melanerpes_aurifrons/)
3) Birds of Europe. Mullarney, Svenson, Zetterstrom, Grant. Princeton University Press, 1999. ISBN-13: 978-0-691-05053-9
4) The Secret Life of Birds. Tudge, Colin, Penguin, 2008.
5) Cornell Lab of Ornithology – All About Birds (Woodpecker page)
Also of interest?
Forget the turkey – RATS are the Christmas treat for this ravenous reynard.
I caught this juvenile fox in the garden this Christmas Eve morning enjoying a little pre-lunch entertainment courtesy of an unfortunate rodent. Very similar to watching a cat play with a mouse. Here’s the series:
Our star is currently promoting the forthcoming production of Ben Jonson’s Volpone by the Playing Up Theatre Company at the Rondo Theatre in Bath during February, where the Sly Fox has apparently developed a taste for chickens.
Of related interest…
Post by Ed Yong here at DISCOVER on how foxes might be using magnetism to help catch prey.
Not all of them, you understand. But here’s a few I’ve snapped in and around Los Angeles, Santa Barbara and San Francisco on visits over the year.
NOTE: I”M RE-JIGGING THE SLIDE-SHOW RIGHT NOW. SORRY FOR ANY INCONVENIENCE.
I got up yesterday morning at what for me is quite an early hour – 6.30ish. So with no CSI on the box at that time, I chose the healthy option and went for a walk in the park. Where I took this picture:
That’s only kind of true. What I actually took was this picture:
and only later discovered the fine structure of water droplets clinging to the spider’s thread when I got home and fired up the computer.
A beautiful and fascinating sight. But, as per usual, the deeper beauty is in the science behind WHY droplets deposit in such regular patterns.
The News piece describes work by Lei Jiang from the Beijing National Laboratory for Molecular Sciences on the hackled orbweaver spider Uloborus walckenaerius. The authors found that if you get in close enough, spiders’ silk appears not as a simple thread but is covered in puffs of minute nanoscale fibres. When the puffs get wet they contract into tight beads or knots connected by thinner pieces of silk, necklace fashion. Additional water migrates and accumulates on the rough surface of the knots in preference to the smoother connecting silk, forming the uniform droplets we see. The research also inspired thoughts around practical offshoots, like the possibility of a man-made equivalent for the manufacture of highly water absorbent materials.
I didn’t see any ‘puffs’, but I’m pretty pleased with the resolution I achieved with a good but relatively straightforward camera. That said, I’m feeling the need to get some of that spider silk under the microscope.
Here’s one more picture taken on the same day, of a single strand of web stretching between two trees; would you believe a distance of over 20ft?
The water is clearing from one portion, and the dry filament is just visible in the close-up view. In the technical jargon, we can say the ratio of droplet size to silk diameter is ‘amazing’.
And if you’re wondering where the spider/s were all this time? Me too. For the arachnophiles, here’s one I took earlier.