Saturday, April 13, 2013

Bird Sense by Tim Birkhead

Bird Sense: What It's Like to Be a Bird
by Tim Birkhead
Bloomsbury, 2012
265 pages

I have absolutely no excuse for taking over a month to finish this book, because it's really fantastic. It should be no surprise to anyone that I might like this book; it's a popular science book about birds. Written by a scientist who really knows how to write in a way that makes the science intelligible to outsiders but not patronizing. Written by a man who really, really loves birds. This is the perfect kind of book for me.

The central question: how much do we know about a bird's senses? How do they see? Touch? Hear? Taste? Smell? How do they navigate using the earth's magnetic field? What role, if any, does emotion play in the life of a bird? Birkhead is basically giving us a sense-by-sense overview and synthesis of the research, from as far back as Aristotle to the most recent (as of publishing) fMRI studies of birds' brains. He does so in a fairly informal but also rigorous way, adding his own personal anecdotes and opinions where appropriate and necessary, but always (as any good scientist should) hedging his bets. It's essentially a massive literature review written with an eye to convincing and enlightening the layperson.

An example, though this is a fair bit more chatty than much of the book:

There is an apparent contradiction here: on one hand I'm saying that the bird's beak is much more sensitive than is generally supposed, but on the other you may be wondering about woodpeckers using their bills as an axe. How can a beak be simultaneously sensitive and insensitive? The answer is: our hands work in exactly the same way. Formed as fists, our hands become weapons, but opened flat they are capable of the most sophisticated sensitivity -- exemplified by Wilder Penfields' hugely handed homunculus. A woodpecker hacks wood using the sharp, insensitive tip of its beak; it doesn't use the much more sensitive inside of its mouth. My concern is for those wading birds like the woodcock and kiwi whose bill tip is relatively soft and incredibly sensitive. What happens if they inadvertently hit a rock by mistake when probing in the soil? Is this the human equivalent of banging your funny bone?

And there is a pleasant surprise here: Birkhead uses his opportunity to tell his audience how science works. His audience is likely fairly specific -- generally those already interested in birds, mostly, or zoology in general, or possibly psychology -- but they're not universally scientifically-minded, so he breaks down the scientific process, explicitly, in the introduction. We're also reminded constantly that scientific "truth" is, as he puts it, more accurately "truth-for-now" while we wait for someone to upset our current understanding of the world. This becomes abundantly clear as we move through examples; the chapters on birds' senses of taste, touch and smell are particularly full of "we thought this, then we thought this, and then someone did this and now we're starting to realize this..." All of this is, of course, as applicable to any other field of scientific study as it is to ornithology.

Even just applicable to ornithology, though, it's a wake-up call. I don't know how long I've been perpetuating the myth that birds, outside of a few exceptions, can't smell. Apparently this is quite far from the truth, at least for significant numbers of species. Birkhead even discusses the fact that some sea birds, like albatrosses and petrels, probably use a sort of "scent landscape" to help them find their prey -- meaning that those birds, at least, have a far better sense of smell than humans. Ravens and vultures have no problem finding fresh carcasses -- and knowing when they are past their delectable prime. Most birds likely have at least some rudimentary sense of smell, or are able to smell an extremely selective set of things. I can take some comfort in the fact that there are textbooks and field guides still published with the "birds can't smell" fallacy in them, but really. It's been known since the 1960s that birds can smell things. So there's a lesson in how long a particular piece of incorrect trivia can hang around.

Quite apart from carefully popping myths, Birkhead loves the history of ornithology. This is clearly a passion. He's written an entire book on the subject, The Wisdom of Birds, which I'll be on the lookout for. He knows an incredible amount about the historical research and attitudes, regularly bringing ornithologists from the 1800s or earlier into the discussion. Some of them are well-known -- Darwin, Audubon -- while others are more obscure but important. I was particularly taken with the story of Betsy Bang, the medical illustrator in the 1950s who started to really feel that we had the whole smell thing wrong, based on the drawings she was doing to accompany her husbands' scientific papers.

Anyway. I could keep going. The book isn't entirely perfect; though interesting, I felt that the final chapter, the one on bird emotions (if they have them; like Birkhead, I am inclined to think they do in some form or another) to be relatively weaker than the others largely due to less research and therefore less for Birkhead to discuss. While I understand the reason for the order of the chapters, it doesn't end the book well. The postscript goes some way to addressing that, because it's quite strong, but it's not long enough to satisfy. But really, other than that small nitpick, I loved this book. I'll be watching for other Birkhead books, and I'll be buying this one for my collection. I'm rather hoping he does a second edition in ten years, so we can find out what else we've been wrong -- or right -- about in the upcoming decade.

I'll leave you with a bit about guillemots, which I've always liked, but which may now be some of my favourite birds thanks to Birkhead (a hide, for those not versed in British birding terms, is also known as a blind):

While conducting my PhD on guillemots on Skomer Island I constructed hides at various colonies to be able to watch their behaviour at close range. One of my favourite hides was on the north side of the island where, after an uncomfortable hands and knees crawl, I could sit within a few metres of a group of guillemots. There were about twenty pairs breeding on this particular cliff edge, some of them facing out to sea as they incubated their single egg... On one occasion a guillemot that was incubating suddenly stood up and started to give the greeting call -- even though its partner was absent. I was puzzled by this behaviour, which seemed to be occurring completely out of context. I looked out to sea and visible, as little more than a dark blob, was a guillemot flying towards the colony. As I watched, the bird on the cliff continued to call and then, to my utter amazement, with a whirr of stalling wings, the incoming bird alighted beside it. The two birds proceeded to greet each other with evident enthusiasm. I could hardly believe that the incubating bird had apparently seen -- and recognised -- its partner several hundred metres away out at sea.

Birds? Amazing.


Nan said...

Wonderful! This is so interesting. I wonder if he talks about something I puzzle over. Do the same birds come back to nest in the summer, or are they descendants who have some memory of being born there? And the same with bird feeders. And where do they go at night? Do they sleep in a nest where eggs were laid?

Unknown said...

Hi Nan, I think it's species-dependent, whether they return to nesting and foraging and roosting areas each year. A piece of trivia (hopefully correct!) that I have in my head is that Horned Larks, for example, do return to the place where they were born when they're ready to nest, both adults who have nested there previous seasons as well as the young who have never nested before. Birkhead talks about the guillemots breeding on the same site for as many as twenty years, right down to the centimetre! How they can recognize the exact same spot on a cliff year-to-year, I can't imagine. Pretty incredible stuff.

As for roosting, he doesn't really go into that at all. I know owls roost during the day often in the same spot in a tree each day (not necessarily a nest, but maybe a cavity, though I know not always that either) but as for diurnal birds, I have no clue. I'm sure there are people out there who must know though!

Nan said...

That is just fascinating about the guillemots. A miracle.