Tim Birkhead’s 'Bird Sense: What It’s Like to Be a Bird'
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Had nature not evolved birds, would we dream of flight? Would we be sufficiently inspired by the dragonfly, the butterfly, the bee?
No other class of animal has engendered a passion strong enough to require a category neologism – no fishwatchers, insectwatchers or mammalwatchers. So why birds? They are not cuddly, and they are not much like us, at least not in a way that is immediately apparent. Given their distance from us on the evolutionary tree (descended as they are from dinosaurs), it is remarkable that a few species of Aves can bond and communicate with humans so easily.
I have had crows, galahs, cockatoos, frogmouths, thrushes and ducks as house guests, and a vicarious understanding of what it might be like to have wings was given to me by a pet raven in Central Australia. He would perch on my shoulder while I climbed an escarpment. At the top, he would gather himself for flight, and I could sense that gathering in my own body. He would lift himself up with a few strokes and coast down the airways to the bottom to wait for me, or circle the updrafts, watching me first with one eye, then the other, chattering and cawing and clacking and gurgling in his own rich language. It was Tinbergen, I think, who said that ethology is the science of interviewing animals in their own language. (A lovely phrase, taking the study of animal behaviour out of the lab and into an animal’s habitat.)
Back then, when I lived close to nature, that is to say, without a roof, I could identify pretty much any Australian bird – not to the degree of difference that exists between, say, a great egret and an intermediate egret, but enough to be able to say, with confidence, ‘egret’. I can no longer reach a lot of that knowledge – I call it the tectonic plate principle, by which whole continents of information are buried under other continents.
But I am back in my home continent now, so an invitation to join the Werribee Weirdos was a chance to retrieve some of those buried facts and rehabilitate them to memory. It was also an honour, though driving slowly around sewage ponds in the rain with a carload of twitchers and twitcher wannabes may not be everyone’s idea of a great day out.
True twitchers have to be slightly Aspergic, I think, at the poet–naturalist end of a spectrum along which also lie trainspotters and savants. In the company of the really gifted, dilettantes like me can only feel awed. They are extraordinarily knowledgeable and observant people. Perhaps the talent is a remnant of hunting behaviour – an engagement with the fugitive object so intense that it dissolves ego, binding bird, watcher and the space that contains them. In any case I have never met an unpleasant twitcher. Nor can I imagine a twitcher being an axe murderer.
So there we were, parked by a sewage pond, binoculars trained at water birds, lots of them, many of them transient visitors born and bred far to the north, where you would think the weather couldn’t be that much worse than here. But of course, it’s not the warmth that brought them, it’s the food. And a chance to reproduce. These migrants could be sure of a feed and hospitable reeds at Werribee, rather than a hail of shot.
We noted down 77 species. There were blue-billed, Pacific black, musk and pink-eared ducks. There were Australasian shovelers and hoary-headed grebes. There were cormorants (little pied, pied and little black), there were ibises, spoonbills, egrets (see above) and there were swamp harriers and kestrels (“hard as a blade’s curve” as Judith Wright described them) being chased by avian parents. Chats, warblers, cisticolas; chestnut teals and red-kneed dotterels. But is it possible to convey the singular thrill of seeing, as she peeked out briefly from the reeds, my very first buff-banded rail?
For those who still think birds are stupid, your education might begin by reading Tim Birkhead’s Bird Sense: What It’s Like to Be a Bird (Bloomsbury, $35.00), a wonderful if slightly Aspergic book filled with extraordinary facts and charming passion.
Of course, nothing but a bird knows what it’s like to be a bird. But scientists these days are encouraged to make big claims on their book jackets concerning the mysteries of consciousness. Given that we are a long way from understanding human consciousness, avian consciousness, with capacities and equipment often quite different from our own, can be nothing but alien. But humans can imagine; it is part of our own equipment. And researchers are finding clever ways to elucidate behaviours and abilities in birds to help us do just that.
The preface opens with a tragedy, which is not hard to find in these days of the Anthropocene. There are only a relative handful of bird species left thriving in New Zealand, ravaged, as they have been, by introduced predators. The air is oddly empty and silent. The author is there to find out what it is like to be a kiwi, “plodding through the undergrowth in almost total darkness, with virtually no vision, but with a sense of smell and of touch so much more sophisticated than our own”.
He soon admits that it’s simplistic to ask what it’s like to be a bird, and breaks the question down into a list of more specific elements. Such as: “What does it feel like copulating for a mere tenth of a second, but over one hundred times a day?” Or: “What is it like to feel a sudden urge to eat incessantly, and over a week or so become hugely obese, then fly relentlessly – pulled by some invisible force – in one direction for thousands of miles?”
As if that might make it easier.
After that, the book is structured in sections according to the senses: sight, hearing, touch, taste, smell, magnetic sense and emotions. Each has its delights and wonders. Birkhead reveals the histories of naturalists and ornithologists as well as what they discovered, and where research is at now, regarding the avian brain.
Take James E Harting, a falconer, learning how falcons were trapped in the Netherlands in 1877. First you get your great grey shrike (a type of butcher bird) and build it a little turf hut to perch upon. Then you wait until, eventually, the shrike begins to chatter nervously, crouch and point, before retreating into its turf hut. Some time later, a speck appears on the horizon. It is a falcon. “As the raptor approaches,” Birkhead writes, “the nature of the shrike’s agitation informs the falconer of the species [and] how the raptor is approaching; swiftly or slowly; high in the sky or low over the ground.”
The other way to do it is to use the shrikes as decoys. Raptors have superhuman visual acuity because they have “two visual hot spots at the back of each eye” rather than one like us. The shrikes, deprived of their turf house, are sitting … shrikes.
Then there’s the question of how a female bird views a glamorously feathered male, or the lures that a male has made to attract her interest. Australia’s satin bowerbird, for instance, finds sunny spots to show his plumage off to best advantage. Some birds of paradise, however, create their own spots of sun on the dim forest floor by pruning nearby trees. Magnificent male displays have not evolved because they enhance survival (on the contrary, all that heavy and expensive finery and loud courting song can make an individual more vulnerable to predators) but because females like them (they increase reproductive success). All that showing off means the bird has the genetic riches to be able to afford to do it.
So just how is a male’s glory perceived through a female’s eyes? Humans have three types of colour-sensitive photoreceptors in the retina which can absorb red, green and blue light. These three give us access to the range of colours which make life worth living. Birds, however, have four, along with others containing an oil which gives them access to a spectrum which is frankly beyond our ken.
Birds can also use each of their eyes simultaneously for separate functions – one eye scanning for a predator, the other checking for food. An Australian researcher noticed that, during the final days of incubation, the embryo in an egg “turns its head to its left side so that it occludes its left eye but not its right eye”. She surmised that the light reaching the right eye through the shell established visual lateralisation in the brain, determining the subsequent role of each eye. And no, I don’t think this means we can know what it feels like to have one eye doing one thing while the other does something completely different. Or what it feels like to sleep with one of those eyes open, even on the wing.
The section on hearing finds Birkhead crawling through the dark wet grasses of the Nene Washes with an ornithologist friend in the middle of the night. They are trying to capture corncrakes by reproducing their calls on a tape. A corncrake gets to within centimetres of the professor’s head and answers the tape. Its call registers 100 decibels, about the equivalent of stereo headphones turned up to the max. The question is posed: “Why doesn’t this damage the corncrake’s ears?”
It turns out that we know even less about avian hearing than avian seeing. Structurally, we share the same basic audial architecture, though birds lack the outer fleshy bit which, for us, collects and funnels sound waves to the apparatus inside the head. But we can damage and irrevocably lose the hair cells which register those waves in a fluid. Birds keep reproducing them. So that raucous corncrake will never go deaf, as an old rock star would do.
Other birds’ auditory brain areas can shrink and grow, according to the season. Handy for conserving energy outside of breeding times. And would anyone have guessed that nightingales in Berlin have to sing louder than their rural cousins, and sing more loudly on weekdays during rush hour? Which leads me to wonder what deafening decibels Sydney’s cockatoos will one day reach, in order to deal with Kings Cross on a Friday evening.
When it comes to the sixth sense – by which migratory species process the Earth’s magnetic field via a compass-like mechanism in the eye while magnetite receptors in the beak stand in for a map – we are left without any kind of equivalence.
In other ways, however, bird behaviour can be uncomfortably recognisable. There is a harrowing description of guillemot behaviour on an island on which they breed. Usually these birds are not only amicable, they help each other with nestlings. But one year a crash in the eel population put huge food-stress on the community, and once-helpful neighbours turned into psychopaths. “Guillemot chicks were picked up … and swung around in the air, before being tossed off the cliff.” One can learn a lot from books like this, not just about other species, but about our own.
Perhaps our love for birds is not to do with their colour, their dancing, their music, their architecture, their queerly configured brains, their mighty migrations, nor even their ownership of the air, a medium we cannot colonise. Perhaps it is that they do not need us. Alfred Russell Wallace, who, together with Darwin, dislodged man irrevocably from the centre of creation, wrote movingly of this independence, in reference to the birds of paradise he had seen in New Guinea:
I thought of the long ages of the past, during which the successive generations of this little creature have run their course – year by year being born and living and dying amid these dark and gloomy woods with no intelligent eye to gaze upon their loveliness, to all appearances such a wanton waste of beauty … This consideration should surely tell us that all living things were not made for Man. Many of them have no relation to him, their happiness and enjoyments, their loves and hates, their struggles for existence, their rigorous life and early death, would seem to be immediately related to their own well-being and perpetuation, alone.
Perhaps birds are all we have left of the angels. In any case, not to notice them or wonder about them seems a terrible waste of consciousness.