Who's Kenn? Simply put, Kenn is a national treasure. A renowned birder, author, and conservationist, Kenn Kaufman has spent his life dedicated to observing birds, reading about birds, writing about birds, and sharing the world of birds with others. With all that birdy knowledge in his brain, he also acts as the field editor for Audubon magazine. So, whenever we have a bird question stumping us around the office, we just ask Kenn. And now you can, too! If you have a bird or birding question you'd like Kenn to answer, leave them in the comments below or on Facebook. Maybe next month you'll get the kind of thorough, thoughtful, and even humorous response from Kenn we've grown so fond of over the years. —The Editors
Question: Which modern-day birds do you think are most like dinosaurs?
Kenn Kaufman: At the end of the first Jurassic Park film there’s a scene in which the survivors, having narrowly escaped being killed by various dinosaurs, are leaving Isla Nublar by helicopter. The main character looks out the chopper window and his gaze settles on a flying flock of Brown Pelicans. The camera lingers on the pelicans, and without a word, the message comes across: They’re still here. We still have living dinosaurs, but now we call them birds.
As a little kid, I was fascinated with dinosaurs before I started to notice birds, so I’ve been thrilled to follow research that has established more and more firmly that our feathered friends today are directly descended from those ancient thunder lizards. Indeed, many researchers today say that we can’t draw a dividing line between dinosaurs and birds, because the evolution proceeded so smoothly and gradually. The science itself has continued to evolve, too, as more and more fossils are discovered and as analysis of these remains becomes more sophisticated.
As recently as a few decades ago, dinosaurs were all depicted as reptilian things covered with olive-green scaly skin. The only widely recognized ancient bird was Archaeopteryx, known from fossils from about 150 million years ago. Archaeopteryx had teeth and a bony tail, but the fossils clearly showed it had feathers, and it seemed as if this odd feathered thing had just suddenly appeared on the ancient scene. But now we know that other birdlike creatures appeared earlier than Archaeopteryx. What’s more, many dinosaurs had feathers. And their plumage was not only colorful in some cases, but even had glossy iridescent hues!
This changing view complicates the question about which modern birds are most reminiscent of their ancient ancestors. Are we still thinking of dinosaurs as khaki-drab scaly dragons with slathering jaws, like the velociraptors in Jurassic Park, or do we now picture them as brightly plumed creatures flouncing about the landscape? In the face of that uncertainty, my fallback is to focus on groups of birds with the longest evolutionary history.
Based on genetics and on the fossil record, there’s general agreement that the most primitive groups of birds today are several families of flightless ground-dwellers—ostriches, emus, cassowaries, rheas, kiwis—plus the tinamous, which can fly, but not very well. Intriguingly, there’s good reason to believe that these big heavy terrestrial birds all evolved from ancestors that could fly. So their current flightless condition is not, in itself, connected to their primitive status.
By about 66 million years ago, “regular” dinosaurs still flourished alongside a wide variety of birds, many of which undoubtedly flew well and lived in trees. Then a massive asteroid hit the Earth. As Hannah Waters described for Audubon two years ago, the resulting cataclysm evidently destroyed most of the forests, so small ground-dwelling birds would have had an advantage while most tree-dwelling birds died out. When the skies finally cleared, the way was open for the survivors to spread and evolve to fill an abundance of new niches.
The upshot of this is that if any bird today resembles a dinosaur, it doesn’t mean that it simply retained those traits since ancient times. Instead, it suggests that the bird has evolved in a direction that makes it seem similar to those creatures of old. In that view, there’s no wrong answer to the question of which modern bird is most dino-like, so we can just let our imaginations take over.
So, which birds today make me feel as if I’m experiencing dinosaurs?
Well, tinamous are strong candidates. These ground-walkers of the American tropics certainly look primitive, with round bodies, thin necks, and small, geeky heads. But usually we don’t see them at all, because they hide so effectively in dense forest and thickets. Because of this, I’ve experienced them mainly through their voices, but when I hear their haunting, hollow whistles, I always feel as if I’m hearing echoes from a much earlier time.
Then there are kiwis. These New Zealand endemics are usually depicted as comical misfits, with long beaks and hairlike feathers, like a cross between a snipe and a muskrat. But in the wild, they don’t seem comical. I’ve been out at night seeking North Island Brown Kiwis, and their voices are stunning up close: the maniacal whistles of the males, and the harsh gnashing cries of the females, like the sound of ripping flesh. Hearing those noises in the dense, dripping darkness, I could imagine I’d stepped back in time about 70 million years.
But my ultimate dino-bird would have to be the Southern Cassowary. In the rainforest of northeastern Australia, we had been searching a long time before we finally found it—or, maybe, it found us. Suddenly the bird was very near, and very large: standing more than four feet tall, probably weighing a hundred pounds, draped with shaggy furlike feathers, its head crowned with a tall bony plate, it was walking deliberately in our direction. The first thing I noticed was its massive legs and feet with sharp claws, and I remembered reading that cassowaries had been known to kill people with powerful slicing kicks. Then I noticed its eyes: the cassowary was looking at us with a cold, fearless glare, as if sizing us up. At that moment, it seemed this bird could have fit right into a scene in Jurassic Park, and I decided that this was pretty much a dinosaur experience—or close enough.
Q: Why do birds sing so much more at dawn than they do at other times of day?
KK: If you’ve tried to sleep late with the windows open in spring or early summer, you’ve probably noticed the burst of birdsong—the dawn chorus—that begins at the first hint of light in the east, or even before. The caroling from myriad voices goes on and on, seemingly without a pause, gradually winding down after the sun is above the horizon.
Although birds make a wide variety of vocalizations, from alarm calls to simple contact notes, the sounds defined as songs are generally more complex. Birds sing primarily in the breeding season, and they do it mainly to announce their claim to a nesting territory and to attract a mate—or to communicate with a mate if they already have one. A rich, strong song is also a way for an individual to show how fit it is, just as bright plumage may help demonstrate a bird’s fitness. Males do most of the singing, but ongoing research shows that female birds may sing more than we used to believe. Still, the main functions are the same.
A migratory male bird arriving on its territory in spring may sing a lot at first, because other migrants will be arriving or passing through, so there’s a high priority to attracting a mate and to warning other males to stay away. After the main migration season is over, singing still serves to keep the pair in touch, and to defend the turf. For most kinds of birds, that breeding territory has to provide all the needs of the adult pair and their young through the nesting season. A pair of Yellow Warblers, for example, will drive away other Yellow Warblers that cross their invisible border. This instinct should ensure that no interlopers will deplete the supply of the particular insects they crave to feed themselves and their nestlings.
But why sing so early in the morning? One big reason is that most small birds migrate at night. As long as migration season lasts, dawn is the time when newly-arrived individuals are most likely to show up, so it makes sense for territory holders to sing at that time to warn such arrivals to keep moving. After the migration winds down, unmated “floaters” still wander the countryside, and dawn is a good time for territorial birds to reassert their claims.
The other main reason is even simpler: At the first hint of light, there’s nothing better to do. Owls and nightjars may be making their final forays of the night, but for most birds, it’s too dark for them to do much. Rather than trying to scope out food in the dimness, it’s more efficient for them to use this time to communicate about how strong and fit they are, to reassure their mates that they made it through the night, and to advertise their claims to this particular territory. So that robin outside your window that wakes you up at four in the morning isn’t trying to cut into your sleep, and it isn’t just overflowing with musical joy; it’s following instincts that have helped ensure the survival of the species for millennia.
Q: I was birding in Europe and I noticed that hardly any of the songbirds there had crests, while here in North America, there are many crested birds. Why is that?
KK: That’s a great observation. When we see a bird with a perky crest, it captures our attention right away, but it takes keen powers of observation to notice a lack of crests.
Frst, though, what exactly is a crest? It’s merely an elongated group of feathers on the top of the head. Only a minority of species have crests, but this feature crops up all over the world, with examples in many families of birds. Here in North America, for example, we see very prominent crests on Northern Cardinal and Pyrrhuloxia—but not on other members of the family Cardinalidae, such as Painted Bunting, Rose-breasted Grosbeak, or Summer Tanager. But another relative, Blue Grosbeak, has elongated feathers on the forehead that often give the head a slightly pointed or peaked appearance, perhaps reflecting a stage in how a crest could evolve.
Most kinds of crested birds can control these feathers, raising or lowering them at will, and the position of the crest serves as a form of communication. Blue Jays and Steller’s Jays have their crests lowered most of the time, appearing as points extending back from the back of the crown. If they raise their crests high, it typically signals some kind of alarm, stress, or aggression. Likewise, if a Cedar Waxwing raises its pointed crest, it’s probably anxious about something. Northern Cardinals, by contrast, often have their crests raised, and may flatten them in aggressive encounters. Tufted Titmice and related species may raise their crests high when they’re asserting dominance over others of their kind, and may flatten them when they’re afraid. So the signals vary in meaning among different kinds of birds, but the position of the crest usually communicates something to other members of the same species.
Here’s an interesting pattern: crested birds, in general, are not long-distance migrants. In the plover family, for example, the round-headed American Golden-Plover migrates from the high Arctic to the southern tip of South America, but the crested species of lapwings move much shorter distances. Some woodpeckers (like the Pileated) are crested, but the few woodpeckers that migrate notable distances (like Yellow-bellied Sapsucker) are not. In the cardinal family, the round-headed Scarlet Tanager flies to South America for the winter, while the crested Northern Cardinal is sedentary. Why the difference? As far as I can tell, it’s just coincidence. But it’s fun to think about.
So, finally, does North America have more crested songbirds than Europe, and if so, why?
North America north of Mexico has more bird species than Europe. Among the songbirds, a slightly higher percentage do have crests, but the main difference is that they’re much more conspicuous here. In the U.S. and Canada, there are 11 species of jays, but the two with crests, Steller’s and Blue Jays, happen to be very common and widespread. Europe’s two jay species lack obvious crests (although the Eurasian Jay can raise its crown feathers to create a puffy-headed look). Among Europe’s several species of titmice, only one has a crest, but we have five crested titmouse species in North America and they include common feeder visitors. Europe’s one crested species of waxwing is mostly limited to the far north, but in North America we have two species, and the Cedar Waxwing is very widespread. And the Northern Cardinal is one of the most familiar backyard birds for tens of millions of people in the U.S. and southeastern Canada. Europe has nothing comparable to the cardinal. Some of their larks have elongated crown feathers but the ones with the most conspicuous crests, like Crested Lark and Thekla Lark, are hardly backyard birds for anyone.
Take all together, I think the difference is mostly a matter of pure chance. Is that disappointing? I hope not. One great thing about bird study is that even an unanswerable question will lead us to consider all sorts of fascinating sidelights on the way to not getting an answer.