It is amazing how little you can know about something right in front of your eyes. For me, birds are a great example of this phenomenon. After all, they are creatures that I see every day, flying overhead, perching in treetops, floating in fountains, skipping on the ground, filling the air with music. Perhaps arrogantly, I had always assumed that these feathered bipeds were rather dim-witted, acting purely out of blind instinct. Certainly, pigeons do not inspire much admiration. But in this book, Ackerman demonstrates that birds—or at least some birds—are far cleverer than I ever suspected.
This book is full of surprising bird behaviors. Bird song, for example, is not just the mindless repetition of melodies to mark territory, but full of information. Most birds have a repertoire of alarm calls, and use these calls to distinguish between types of dangers (whether a predator is grounded, aerial, acutely or only somewhat dangerous, or a brood parasite). Even more impressive, some birds use alarm calls (often mimicking those of other species) to fool their neighbors, setting off false alarms in order to steal food or defend their nests. And singing is not simply genetic; social learning plays a large role in the process. The superb lyrebird, for example, does not primarily learn its imitative song by mimicking other birds in the area, but by imitating other lyrebirds. And many weeks of diligent practice are required in order to give a passing performance.
One of the most astonishing sections in this book concerns the Australian fire hawks. For decades, scientists have known that birds of prey gravitate towards bush fires, in order to pick off escaping animals. More controversial—but attested to by a great many observers, including Abroginal Australians—is the possibility that these hawks intentionally spread fires by picking up burning sticks and dropping them in a dry patch. If this is true, these hawks would be the only non-human species to intentionally manipulate fire. Another, marvelous chapter describes the intricate behaviors that have developed around army ants. Much like a fire, the marching ants cause other creatures to flee; and some birds have evolved to specialize in this kind of foraging. They even keep track of where the ants nest, and periodically check up on old nesting sites.
My favorite section was on bird intelligence. I had no idea that corvids (crows, jays, magpies, and ravens) were such brainy creatures. Ravens especially are adept at manipulating tools, solving puzzles, and working together in order to solve complex problems. Somewhat less clever, though far more endearing, are the kea parrots of New Zealand. What makes this species so special is their penchant for play, even giving primates a run for their money when it comes to curiosity and buffoonery. Ravens like to play, too, though their curiosity is tempered by a powerful fear of novel objects; they are neophobes, whereas the kea are neophiles. What is more, ravens live in social groups defined by strict hierarchies, with lots of in-fighting, while the kea seem to live in relatively egalitarian arrangements with almost no conflict. It is curious that intelligence could take such different forms.
The final section concerns reproduction, and is equally fascinating. I was most intrigued by the genetic arms race between brood parasites and their hosts. To avoid Cuckoo’s parasitizing their nests, birds learn to make ever-more subtle distinctions between genuine eggs and imposters. Some birds even go a step further, and sing a special note while eggs are incubating, which a fledgling bird must reproduce or risk eviction. But Cuckoo’s respond by ever-more convincing imitations of their hosts’ eggs and young. Nature can be a pretty gruesome place. Somewhat more heartening is the practice of cooperative breeding, wherein unrelated birds work as a team to tend and guard their nest. Ironically, however, this practice may have originated when birds started becoming brood parasites on members of their own species, though this is just speculation.
In all, it is hard for me to imagine a better book on birds than this one. Ackerman is a talented writer who brings a palpable love of the subject into every sentence. More importantly, like any great book on science—maybe any great book in general—Ackerman manages to find the astounding within the mundane, putting some wonder back into our quotidian lives.