We know from previous studies that each starling has a direct influence – and is in turn influenced by – about seven neighbours. We can verify this with the vector plots, tracking the change in direction of a particular bird, and then noting the immediate response of its neighbours. But if that were the limit of the bird’s influence, the murmuration would be sluggish to respond to an outside factor, such as the arrival of a sparrowhawk.
In fact the entity responds as a whole, dividing and twisting to outfox the intruder. It turns out the there is a correlation distance much greater than the separation between immediate neighbours. Indeed, that correlation between distant birds may be as wide as the entire murmuration. It is as if they are bound together by invisible threads, each feeling the tug of the other – a kind of rubbery net, stretching and compressing.
In fact, the murmuration may contain several distinct ‘domains’ of influence, where the flight patterns of groups of birds are highly correlated. In the plot on my workstation, these show up as sub-smears of strongly aligned vectors. They come and go as the murmuration proceeds, blending and dissipating – crowds within the larger crowd.
This is where the focus of our recent research lies. What causes these domains to form? What causes them to break up? Can we trace correlation patterns between the domains, or are they causally distinct? How sharp are the boundaries – how permeable?
This paper, the one that is bouncing back and forth between us and the referee, was only intended to set out the elements of our methodology – demonstrating that we had the physical and mathematical tools to study the murmuration at any granularity we chose. Beyond that, we had plans for a series of papers which would build on this preliminary work with increasingly complex experiments. So far we have been no more than passive observers. But if we have any claim to understand the murmuration, then we should be able to predict its response to an external stimulus.
I am starting to sense an impasse. Can we honestly go through this all over again with our next publication, and the one after? The thought of that leaves me drained. We have the tools for the next phase of our work, so why not push ahead with the follow-up study, and fold the results of that back into the present paper? Steal a march on our competitors, and dazzle our referee with the sheer effortless audacity of our work?
I think so.
THE NEXT DAY I set up the sparrowhawk.
I need hardly add that it is not a real sparrowhawk. Designed for us by our colleagues at the robotics laboratory, it is a clever, swift-moving drone. It has wings and a tail and its flight characteristics are similar to those of a real bird. It has synthetic feathers, a plastic bill, large glassy eyes containing swivel-mounted cameras. To the human eye, it looks a little crude and toy-like – surely too caricatured to pass muster. But the sparrowhawk’s visual cues have been exaggerated very carefully. From a starling’s point of view, it is maximally effective, maximally terrifying. It lights up all the right fear responses.
Come the roost, I set down a folding deck chair, balance the laptop in my lap, stub my gloved fingers onto the scuffed old keyboard, with half the letters worn away, and I watch the spectacle. The sparrowhawk whirrs from the roof of the 4WD, soars into the air, darts forward almost too quickly for my own eyes to track.
It picks a spot in the murmuration and arcs in like a guided missile. The murmuration cleaves, twists, recombines.
The sparrowhawk executes a hairpin turn and returns for the attack. It skewers through the core of the flock, jack-knifes its scissor wings, zig-zags back. It makes a low electric hum. Some birds scatter from the periphery, but the murmuration as a whole turns out to be doggedly persistent, recognising on some collective level that the sparrowhawk cannot do it any real damage, only picking off its individual units in trifling numbers.
The sparrowhawk maintains its bloodless attack. The murmuration pulses, distends, contracts, its fluctuations on the edge of chaos, like a fibrillating heart. I think of the sparrowhawk as a surgeon, drawing a scalpel through a vital organ, but the tissue healing faster than the blade can cut.
Never mind – the point is not to do harm, but to study the threat response. And by the time the sparrowhawk’s batteries start to fade, I know that our data haul will be prodigious.
I can barely sleep with anticipation.
BUT OVERNIGHT,THERE’S a power-outage. The computers crash, the data crunching fails. We run on the emergency generator for a little while, then the batteries. Come morning I drive out in the 4WD, open the little door at the base of the tower, and climb the clattery metal ladder up the inside. Inside there are battery-operated lights, but no windows in the tower itself. The ladder goes up through platforms, each a little landing, before swapping over the other side. Heights are not my thing, but it’s just about within my capabilities to go all the way to the top without getting seriously sweaty palms or stomach butterflies.
At the top, I come out inside the housing of the turbine. It’s a rectangular enclosure about the size of our generator shed. I can just about stand up in it, moving around the heavy electrical machinery occupying most of the interior space. At one end, a thick shaft goes out through the housing to connect to the blades.
The turbine is complicated, but fortunately only a few things tend to go wrong with it. There are electrical components, similar to fuses, which tend to burn out more often than they should. We keep a supply of them up in the housing, knowing how likely it is that they will need swapping out. I am actually slightly glad to see that it is one of the fuses that has gone, because at least there is no mystery about what needs to be done. I have fixed them so many times, I could do it in my sleep.
I open the spares box. Only three left in it, and I take one of them out now. I swap the fuse, then reset the safety switches. After a few moments, the blades unlock and begin to grind back into motion. The electrical gauges twitch, showing that power is being sent back to our equipment. Not much wind today, but we only need a few kilowatts.
Job done.
I think of starting down, but having overcome my qualms to get this high, I cannot resist the opportunity to poke my head out of the top. At the back of the electrical gear is a small ladder which leads to an access hatch in the roof of the housing.
I go up the short steps of the ladder, undo the catches, and heave open the access hatch.
My knees wobble a bit. I push my head through the hatch, like a tank commander. I look around. There’s a rubberised walkway on top, and a set of low handrails, so in theory I could go all the way out and stand on top of the housing. But I’ve never done that, and I doubt that I would ever have the nerve.
Still with only my head jutting out, I look back at the hut, a huddle of pale rectangles. The perimeter circle is hard to trace from this elevation, but eventually I glimpse the spaced-out sentinels of the tripods, with the scratchy traces of my own wheel tracks between them. Then I pivot around and try to pick out the causeway. But it’s harder to follow than I expect, seeming to abandon itself in a confusion of marsh and bog. I squint to the horizon, looking for a trace of its continuation.
Strange how some things are clearer to the eye at ground level, than they are from the air.
Birds must know this in their bones.
THE NEXT DAY, the computers running again, I squeeze our data until it bleeds science. With the vector tracking, we can trace the response to the sparrowhawk across all possible interaction lengths. Remarkable to see how effectively the ‘news’ of the sparrowhawk’s arrival is disseminated through that vast assemblage of birds.
Because there is no centralised order, the murmuration is best considered as a scale-free network. The internet is like that, and so is the human brain. Scale-free networks are robust against directed attacks. There is no single hub which is critical to the function of the whole, but rather a tangle of distributed pathways, no one of which is indispensible. On the other hand, the scale-free paradigm does not preclude the existence of those vector domains I mentioned earlier. Just
as the internet has its top-level domains, so the brain has its hierarchies, its functional modules.
Would it be a leap too far to start thinking of the murmuration as hosting some level of modular organisation?
I jot down some speculative notes. No harm in sleeping on them. In the meantime, though, I write up the sparrowhawk results in as dry and unexciting manner as I can manage, downplaying any of the intellectual thrill I feel. Passive voice all the way. The sparrowhawk was prepared for remote control. Standard reduction methods were used in the data analysis. The murmuration was observed from twenty spatially separated viewing positions – see Fig. 3.
The way to do science is never to sound excited by it, never to sound involved, never to sound as if this is something done by people, with lives and loves and all the usual hopes and fears.
I send the latest version of the paper back to the journal, and cross my fingers.
I OPEN THE glove compartment and take out the latest version of the paper. I skim it quickly, then go back through some of the more problematic passages with the yellow highlighter, before adding more detailed notes in the margin. My initial optimism quickly turns to dismay. Why in hell have they opened up this whole other can of worms? I squint at an entire new section of the paper, hardly believing my eyes.
Sparrowhawks? Robot sparrowhawks? And pages of graphs and histograms and paragraphs of analysis, all springing from work which was not even foreshadowed in the original paper?
What are they thinking?
I’m furious at this. Furious with the journal editor, for not spotting this late addition before it was forwarded to me. Furious with the authors, for adding to our mutual workload. Furious for their presumption, that I will presumably be sufficiently distracted by this to overlook the existing flaws – like a magpie distracted by something shiny. (Except that’s a myth; corvids are not attracted to shiny things at all.)
Furious above all else that they are prepared to squander this good and original science, to slip it into this paper like a lazy afterthought, as a kind of intellectual bribe.
No, this must not stand.
I put the 4WD back into gear. I must settle my thoughts before firing back an intemperate response. But really, I’m enraged. I bet they think they know who I am. I imagine encountering them out here, running them down, feeling the bounce of my wheels over their bodies. I’d stop the 4WD, get out, walk slowly back. Savour the squelch of my boots on the marshy ground.
Their whimpering, their broken-boned pleas.
‘You think this is how we do science, do you?’ I’d ask them, entirely rhetorically. ‘You think it is a kind of game, a kind of bluff? Well, the joke’s on you. I am recommending your paper be rejected.’
And then I would walk away, ignoring their noises, get back into the 4WD, drive off. At night their cries would still come in across the marsh, but I would not let myself be troubled. After all, they brought this on themselves.
But that sparrowhawk, I’ll admit, was beautiful.
I GO OUT to the walk-in traps and collect the overnight haul. There are almost always some birds in the snares, and almost always some starlings. It is how we ring them, bring them in for study, assess their overall genetic fitness. Generally they are none the worse for having been caught up in the nets overnight.
I collect ten adult specimens, let the others go, and take the ten back to the hut.
A firm in Germany has made the digital polarising masks for us. They are elegant little contraptions, similar in design to the hoods fitted around captive birds of prey. These are smaller, though, optimised to be worn by starlings, and to offer no significant resistance to normal flight. Each hood is actually a marvel of miniature electronic engineering. Bulging out from either side are two glassy hemispheres.
In its neutral mode, the bird has an unrestricted view of its surroundings. Each hemisphere, though, is divided into digitally-controlled facets. These can be selectively darkened via wireless computer signals, effectively blocking out an area of the starling’s vision.
The consequence of this – the point of the masks – is that we can control the birds’ collision-avoidance response remotely. By making a given bird think it is about to be struck by another bird, we can cause it to fly in any direction we choose.
Again, it is asking too much of human reflexes to control a bird at such a level. But the computers can do it elegantly and repeatably. Each of our ten hooded starlings then becomes a remote-controlled agent, under our direct operation. Like the robot sparrowhawk, we can steer our agents into the murmuration. The distinction is that the hooded starlings do not trigger a threat response from their seven neighbours; they are absorbed into the whole, accepted and assimilated.
But they can influence the other birds. And by careful control of our hooded agents, we can initiate global changes in the entire murmuration. We can instigate domains, break them up, make them coalesce. Anything that happens under the influence of natural factors, we can now bring about at our will.
By we, of course, I mean I.
Old habits die hard. Science is always done in the ‘we’, even when the work is borne on a single pair of shoulders. But frankly, I am starting to doubt the commitment of my fellow researchers. There is always a division of labour in any collaborative enterprise, and sometimes that division can seem unfair. If the brunt of the work is my responsibility, though, I fail to see why I should not receive the lion’s share of the credit.
As I wait for the murmuration to form, I make some deft amendments to the list of the authors, striking out a name here, a name there.
Feathers will fly, of course.
TEN BIRDS MIGHT not seem much but these birds are like precision instruments, guided with digital finesse. To begin with, we – I – restrict myself to only minor interventions.
I make the murmuration split into two distinct elements, then recombine. Suitably encouraged, I quarter it like a flag. I pull it apart into four rippling sheets of birds, with arcs of clear air between them. The edges are improbably straight, as if the birds are glassed-in, boxed by invisible planes. But that is the power of incredibly delicate control processes, of stimulus and feedback operations happening much too swiftly for human perception. If an edge starts losing coherence, the computer makes a tiny adjustment to one or more of the control starlings and the order is reestablished. This happens many times a second, at the speed of avian reactions.
They have always lived in a faster world than us. They live a hundred days in one of our hours. To them we are slow, lumbering, ogrelike beings, pinned to the ground by the stonelike mass of our bodies. We envy them; they pity us.
I push forward. I carve geometries out of the murmuration. I fold it into a torus, then a ribbon, then a Möbius strip. I do not need to know how to make these shapes, only to instruct the laptop in my desires. It works out the rest, and becomes more adept as it goes along.
I make the murmuration spell out letters, then I coax those letters into lumpy, smeared-out words. I spell my name in birds. They banner around me like the slogans towed by light aircraft. I laugh even as I feel that I have crossed some line, some invisible threshold between pristine science and sordid exploitation.
But I carry on anyway. I am starting to think about those domains, those hints of modular organisation.
How far could I push this, if I were so determined?
ANGRY EXCHANGES OF emails. Editor not happy with this latest change of direction. Much to-ing and fro-ing. Questions over the change in the listed authors – deemed most unorthodox. Accusations of unprofessionalism. If we were in a room together, the three of us, we might get somewhere. Or we might end up throwing textbooks.
Is this a travesty of the way science ought to be done, or is it science at its shining best – as loaded with passion and conviction as the any other human enterprise? No one would doubt that poets squabble, that a work of great literature might take some toll on its creator, that art forges enemies as readily as allies. Why do we hold s
cience to a colder, more emotionless set of standards? If we care at all about the truth, should we not celebrate this anger, this clashing of viewpoints?
It means that something vital is at stake.
Hard in the spitting crucible of all this to remember that every one of us was drawn to this discipline because of a love of birds.
But that is science.
MY PROPOSITION IS simple. The domains are controllable. I can cause them to form, contain the shape and extent of their boundaries, determine the interaction of their vector groups with the surrounding elements. I can move the domains around with the flock. I can blend one domain into another, merging them like a pair of colliding galaxies. Depending on their vector properties, I can choose whether that act results in the destruction of both domains or the formation of a larger one.
I sense the possibility of being able to execute a kind of Boolean algebra. If the domains behave in a controllable and repeatable way, and I can determine their states – their aggregate vector sums – then I can treat them as inputs in a series of logic operations.
The thought thrills me. I cannot wait for the coming of dusk.
With the laptop reprogrammed, I quickly satisfy myself that the elements of my Boolean experiment are indeed workable. I create the simplest class of logic gate, an AND gate. I classify the input domain states as either being 0 or 1, and after some trials I achieve a reliable ‘truth table’ of outputs, with my gate only spitting out a ‘1’ if the two inputs share that value.
I push on. I create OR and NOT gates, a ‘not AND’ or NAND gate, a NOR gate, an XOR and XNOR gate. Each is trickier than the last, each requires defter control of the domains and vector states. To make things easier – at the burden of a high computational load on the computer and the ethernet network – I retrieve more birds from the snares, fitting them with additional digital hoods.
Now I can create finer domains, stringing them together like the modules in an electrical circuit.
The Best Science Fiction and Fantasy of the Year, Volume Ten Page 10
