Tim Birkhead’s Bird Sense: What’s It’s Like to Be a Bird details our current knowledge of birds and the history of how we got to this state. Written for the lay reader, a person with an interest in the world; by which I mean it’s hardly necessary that you be a bird watcher to enjoy this. In chapters titled Seeing, Hearing, Touch, Taste, Smell, Magnetic Sense, and (what?) Emotions, Birkhead examines the world of birds, as much as we can, understanding there’s lots more to know, and probably some things we may never know.
Here are some for instances: birds have major seasonal changes in their internal organs. Sex organs, in particular, grow much larger during breeding in response to hormones triggered by day length. Then they shrink back down to non-breeding insignificance. This may not be all that surprising — the human male equivalent would have our testes shrinking to the “size of apple pips” during football season, when most American males don’t have sex — but parts of the bird brain also expand and contract through the year. This is because bird song, an essential part of territory and breeding, requires more brain power. Birds also hear better during breeding season (at this point Birkhead notes that oestrogen, in the British spelling, makes women think men’s voices sound richer, which I’ll call the Barry White Effect). I’m no instrumentalist, but I realize many humans are nothing if not narcissistic and can only wonder who should care about bird brains, but discovering how brains regenerate annually may have tremendous application for humans, cf. Alzheimer’s. Meanwhile, the hair cells in bird ears are continuously renewed; this isn’t the case in humans, once these babies are dead they’re gone, which is why we start to lose our hearing as we age (and headbangers squander it earlier). Not to be confused with the hairs that grow on the external portion of our primate ears.
Some birds, fowl in particular, use one eye for close-up work, like distinguishing food from pebbles, and one for distinguishing hawks from clouds. Keep an eye on the sky! Raptors are famed for their vision, much more acute than human eyesight, and this book explains the physiological reasons why. And most birds also see UV light as well as the red/green/blue we see. The Kiwi, meanwhile, can barely see at all, but that’s OK because it’s nocturnal and can sniff and feel out buried prey with their very acute bills. Oh, and birds can sleep while they fly. Some birds, like the loud crakes and booming bitterns, can actually block their ears to their own sounds so they don’t damage their own hearing. Owls on the wing fly very quietly; their feathers are adapted to muffle sound, which makes it easier to swoop upon prey, but also so that the sound their own wings make doesn’t interfere with their acute hearing; they can hear animals under the snow. Owls also have excellent night vision, but they can’t fly in complete darkness (unlike bats, who echolocate, as do oilbirds and some swiftlets). On some overcast moonless nights, it is extremely dark in the woods, and one of the ways owls adapt to these times is by getting to know their terrain, sometimes living in it for years, like the back of their wings.
The book is full of such amazing details. Richard Dawkins has noted that “the greatest story ever told” is the history of evolution on earth. Its manifestations are all around us, and make the human fantasies of sky gods snapping their fingers to create life (and then letting the majority of it die off?) paltry stuff indeed.
The book’s simple cover design is a beaut. That’s the British edition pictured above; the U.S. one drops the artist’s name, Katrina van Grouw, whose own book looks amazing, down to the bottom. Inside, there’s this delightful dingbat or hedera (from the Latin for ivy, since the curlicues originally so used as punctuation looked ivy-ish): Unmistakable silhouettes of swifts.