Tag Archives: birds

Delight and devilry

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Reading Douglas Futuyma’s How Birds Evolve for new Scientist, 7 December 2022

In Douglas Futuyma’s evolutionary history of birds, the delight is in the detail, and some of the devilry too — this is not a light read. Futuyma tells a double tale: he explains how the study of birds advanced our understanding of evolution, and he shows how advances in evolutionary science solve some long-standing ornithological mysteries, even as they throw up others.

He has written How Birds Evolve for birders, and being a birder himself (he began bird-spotting around the age of eleven in New York’s public parks), he knows just how fiercely the birding bug can bite. Many are half-way to being field scientists already, and many celebrated field scientists — from Ernst Mayr to Konrad Lorenz to Niko Tinbergen — have been birders.

“I suspect few of my teachers in the 1960s imagined that we would be studying birds by combining information from geology and molecular biology — disciplines that are miles apart,” says Futuyma, giving the reader an early hint of the complexities to come.

Birds are a curious, and curiously productive field of study for evolutionary biologists: less useful in understanding the mechanisms of evolution than insects, plants, and bacteria because they don’t reproduce as quickly, but, being various and everywhere, vital to the study of behaviour, longevity, ecology, speciation, cultural evolution and a host of other specialisms.

The ability to study populations and how they interact gave evolutionary biologists a foretaste of what their science would become. “The models of how variation might persist” Futuyma remarks, “were developed by evolutionary biologists who might not have known a hawk from a handsaw but were adept in mathematics.” Applying lessons from birds to ourselves, though risky, has also proved both irresistible and, at least in the science’s early stages, highly productive. In pondering human evolution, Darwin developed the idea of sexual selection, which takes up more than half his The Descent of Man of 1871. “Darwin devotes four full chapters to birds and cites at least 170 species,” Futuyman points out. “Birds provided more evidence for his ideas about sexual selection than any other group of animals”.

To grapple with bird diversity, one pretty much has to conjure up an idea of evolution. Peculiar and apparently inutile features abound in the bird world, a sure sign of unceasing adaptation. There are also, to complicate matters, many instances of convergent evolution. Feathers may have evolved only once, and through a bizarre genetic accident at that. (They don’t arise easily, as we once assumed, from reptilian scales.) Feather and wing shapes, however, recur again and again in even distantly related species. Darwin once predicted: “Our classifications will come to be, as far as they can be so made, genealogies,” but even his credulity would have been stretched by the news that flamingoes are related genetically to grebes.

“I don’t know how similar to birds a creature would have to be for us to call it an “avioid” or an “ornithoid,” Futuyman speculates, but for it “to be bipedal with feathers, toothless kinetic jaws, highly developed vision, a gizzard, and a high constant body temperature… I think… is very unlikely indeed.”

Futuyma unpacks the story of evolutionary science alongside the story of how birds evolved, acquiring bipedal locomotion and simple filamentous feathers as Dinosauria, then clavicles fused into a wishbone in Theropoda, on and on, until we arrive at what we might as well call the modern bird, with its large, keeled breastbone, rapid growth, and unfeasibly lightweight construction.

How Birds Evolve is not meant to be an introduction to birds (though one imagines readers of this magazine would lap it up). It is personable, entertaining and deeply passionate about its subject.

Futuyma, the author of two successful textbooks about evolution, is out to inspire, and his comprehensive book more than makes up in wonder what it might lack in an easy and seductive narrative.

A baffling accident of history

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Watching Shaunak Sen’s All That Breathes for New Scientist, 28 September 2022 

“Hundreds of birds are falling out of the sky every day,” complains Nadeem Shehzad, by far the grumpier of the two cousins whose life’s work is to rescue the injured raptors and waterbirds of Delhi. “What amazes me is that people go on as if everything’s normal.”

People, in Shaunak Sen‘s award-winning documentary, aren’t the only ones making the best of things under Delhi’s polluted skies. The city is also home to rats, pigs and frogs, mosquitoes and turtles, cows and horses and birds, and especially black kites, who have come to replace vultures as the city’s chief recycling service, cleaning up after the city’s many slaughterhouses and meat processing plants.

The film follows Nadeem, his brother Mohammad Saud and their young cousin Salik Rehman as they struggle to turn their family obsession into [https://www.raptorrescue.org] a fully fledged wildlife hospital. No sooner is yet another funding bid completed then their meat mincer breaks down. No sooner is a wounded bird stitched up than there’s a power cut and all the lights go out. What happens to the family’s sewer connection when the monsoon arrives does not bear discussing.

These struggles are compelling and yet this is not really a film about humans. It’s about, quite literally, “all that breathes”. The humans are just one more animal trying to eke out a living in this alien place called Delhi: not a bad place, but not a human place neither: more a baffling accident of history.

The cousins compare notes on the threat of nuclear war between India and Pakistan while, barely two kilometres away, religious riots tear up the streets. Feral pigs cross a nearby stream. A millipede eases itself out of a puddle, even as a passing aeroplane casts its reflection in the water. The film’s first shot is a sumptuous pan across a rat-infested rubbish dump. Filmed at a rodent’s eye level, bare inches from the ground, a fascinating, complex, dramatic world is revealed. Later, we hear how Hindu nationalists are presenting the city’s muslim population in terms of disease and hygiene. Any European viewer with an ounce of historical sense will know where this thinking can lead.

Whether or not one picks up on all the film’s nested ironies is very much left to the viewer. Sen’s method is not to present an argument, but rather to get us to see things in a new way. Of the film’s main subject, the black kites, Sen has said, “I want audiences to leave the theater and immediately look up”.

Achieving this requires a certain amount of artifice. Viewers may wonder how it is that a tortoise reaches the top of a pile of garbage just in time to watch a motorike career around a distant corner. Individual shots took days to capture; some took much longer. The human conversations are a little more problematic. After consuming so many slipshod hand-held documentaries, I found the conversations here a little too on-message, a bit too polished to be true.

But why cavil at a powerful and insightful film, just because its style is unfamiliar? Filmed between 2020 and 2021 by German cinematographer Ben Bernhard, supported by Riju Das and Saumyananda Sahi, All That Breathes inhales extreme close-ups and cramped interiors, exhales vertiginous skyscapes and city skylines.

The story of Delhi’s black kites, regularly injured by the glass-coated threads used to fly paper kites — one of Delhi’s favourite leisure activities — might have been better served by a more straightforward story. But then the kites would, in the same breath, have become a small, contained, even inconsequential problem.

The whole point of Sen’s film, which won a Grand Jury prize at this year’s Sundance Film Festival, is that the kites are a bell-weather. We’re all in this emergency together, and struggling to fly, and struggling to breathe.

Not quite a coincidence

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Reading Antone Martinho-Truswell’s The Parrot in the Mirror for New Scientist, 9 March 2022

Organisms adapt over evolutionary time to their changing surroundings. This creates, over time, a living world of quite jaw-dropping diversity. It also generates some astonishing coincidences — if “coincidence” is quite the right word to describe how two quite unlike species, adapting to identical environments, end up looking and behaving the same. For instance, the pangolins of Africa and the armadilloes of South America look like close cousins; in fact they’re more closely related to humans than they are to each other.

Convergent evolution doesn’t have to be so visually obvious. Take humans and birds: few readers will take on trust Sydney-based zoologist Martinho-Truswell’s assertion that we “look like a strangely featherless bird”.

By the time I finished The Parrot in the Mirror, though, I found that image both compelling and reasonable. Martinho-Truswell explores the traits shared by humans and birds, from our unusual longevity to our advanced social skills, from our parenting styles to our intelligence and even our use of language. These, the author argues, are all extraordinary examples of convergent evolution at work.

Crudely, Martinho-Truswell’s argument goes like this:

Once birds could fly, they could elude almost all predators. And since they were unlikely to be eaten in any given year, it made sense for birds to go on living, producing more eggs and offspring. Increased longevity followed. With longevity came increased intelligence. Long-living animals need to be smart because they get to be the parents of young who develop over a longer period. And because longer development requires a bigger egg and a bigger yolk sac, and because an egg can only get so big, most birds hatch out very immature, helpless young, that require enormous amounts of care. This care is provided by pair bonded parents, sometimes supplemented by a larger community, hence the evolution of complex social behaviour and language (or song, at any rate).

The human story is a twisted mirror-image of the avian one. Communal behaviour among primates promoted the evolution of intelligence, and this reduced the likelihood of predation. Longevity followed, boosting intelligence further, to the point where big-brained human young have to be born immature and helpless so as not to kill their mothers in childbirth.

For different reasons, then, humans and birds evolved measurable intelligence. But how do we compare our abilities? Can we even talk about bird smarts and human smarts in the same sentence?

Martinho-Truswell’s handling of this subject is very well done. A balance has to be stuck between precision and imagination. On the one hand, a duckling’s ability to imprint upon its mother shortly after the moment of its birth puts it well ahead of chimpanzees, parrots, pigeons, crows and even human children, but this one hardwired ability doesn’t necessarily make the duckling more intelligent. On the other hand, it would be a dull observer indeed that did not see in Irene Pepperberg’s thirty-year study of language use in Alex, an African Grey parrot, quite staggering evidence of advanced cognition. (Alex not only asked questions; it asked them, and got annoyed if people offered dumb responses.)

Containing the niceties of convergent evolution in a straightforward narrative is not easy. Evolutionary causes and effects do not follow each other in neat, storybook fashion, and there’s always the temptation, reading this book, to take Martinho-Truswell’s acts of narrative shorthand at face value and suppose that humans, 50 million years behind parrots in the evolution of intelligence, somehow became more human by actually mimicking their distant avian cousins. (Distant cousins indeed, by the way: the last common ancestor of birds and mammals died out 320 million years ago.)

But it is surely better to be very slightly misled by a gripping story than to be bludgeoned by a dull one. Martinho-Truswell has written a superb introduction to a surprisingly complex and fraught field of study. Having read it, you will not look at yourself in the mirror in quite the same way.

 

In praise of tiny backpacks

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Reading The Bird Way by Jennifer Ackerman for New Scientist, 17 June 2020

Visit the Australian National Botanic Gardens in Canberra, and you may stumble upon an odd sight: a human figure, festooned with futuristic-looking monitoring gear. Is it a statue? No: when children poke it (this happens a lot) the statue blinks.

Meet Jessica McLachlan, a researcher at Australian National University, at work studying the fine, never-before-detected details of bird behaviour. The gear she wears is what it takes to observe the world as birds themselves see it. Not to put too fine a point on it, birds are a lot faster than we are.

Bird brains are miracles of miniaturisation. Their neurons are smaller, more numerous, and more densely packed. They differ architecturally too, cramming more and faster processing power into a smaller space.

This means that in the bird world, things happen fast — sometimes too fast for us to see. (Unless you film blue-capped cordon-bleus at 300 frames-per-second video, how could you possibly know that they tap-dancing in time with their singing?)

Modern recording equipment enables us to study an otherwise invisible world. For example, by strapping tiny backpacks to seabirds, and correlating their flight with known ocean activities, we’ve discovered that birds have a quite extraordinary sense of smell, following krill across apparently featureless horizons that are, for them, “elaborate landscapes of eddying odor plumes.”

Science and nature writer Jennifer Ackerman’s fresh, re-invigorated account of the world of birds is arranged on traditional lines (sections cover her subjects’ singing, work play, love and parenting), but it is informed, and transformed, by accounts of cybernetically enhanced field studies, forensic analyses and ambitious global collaboration. She has travelled far and talked to many, she is generous to a fault with her academic sources, and her descriptions of her visits, field trips and adventures are engaging, but never obtrusive.

Her account centers on the bird life of Australia. This is reasonable: bird song began here. Songbirds, parrots and pigeons evolved here. In Australia, birds fill more ecological niches, are smarter, and longer-lived.

Like every ornithological writer before her, Ackerman is besotted by the sheer variety of her subjects. One of the most endearing passages in her book compares parrots and corvids. Both are intelligent, highly social species, but, after 92 million years of evolutionary separation, the similarities stop there. Ravens are frightened of novelty. Keas lap it up. Keas, confronted by a new researcher, will abandon a task to go play with the stranger. Ravens will simply wig out. Ravens have a strict feeding hierarchy. Curious male Kea will good-naturedly stuff food down an unfamiliar youngster’s gullet to the point where it’s fending them off.

Ackerman’s account is often jaw-dropping, and never more shocking than when she assembles the evidence for the cultural sophistication of bird song. Birds decode far more from sounds than we do and until recently we’ve been deaf to their acoustic complexity. Japanese tits use 11 different notes in their songs, and it’s the combination of notes that encodes information. Swap two notes around, and you elicit different responses. If this isn’t quite syntax, it’s something very like it. The drongo has absolute conscious control over its song, using up to 45 mimicked alarm calls to frighten other species, such as meerkats, into dropping their lunch — and it will target specific warning calls at individuals so they don’t twig what’s going on.

Meanwhile, many different species of bird worldwide, from Australia to Africa to the Himalayas, appear to have developed a universal, and universally comprehensible signal to warn of the approach of brood parasites (cuckoos and the like).

If the twentieth century was the golden age of laboratory study, the 21st is shaping up to become a renaissance for the sorts of field studies Charles Darwin would recognise. Now that cybernetically enhanced researchers like Jessica McLachlan can follow individuals, we have a chance to gauge and understand the intelligence exhibited by the animals around us. Intelligence en masse is, after all, really hard to spot. It doesn’t suit tabulation, or statistical analysis. It doesn’t make itself known from a distance. Intelligent behaviour is unusual. It’s novel. It takes a long time to spot.

If birds are as intelligent as so many of the stories in Ackerman’s eye-opening book suggest, then this, of course, may only be the start of our problems. In Sweden, corvid researchers Mathias and Helena Osvath have befriended a raven who turns up for their experiments, aces them, then flaps off again. “In the ethics section of grant applications,” says Matthias, “it’s difficult to explain…”