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 on Facebook or send us an email. 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: Is there a difference between bird songs and bird calls, or can we use those terms interchangeably?
Kenn Kaufman: Bird listening can bring just as much fascination as bird watching, and part of the reason is that most species make a wide variety of different sounds. This is especially true among the Passeriformes, the so-called perching birds or songbirds, which make up more than half the total bird species in the world (or pretty much everything in the latter half of your favorite field guide). Most of these have impressive playlists of sounds. For example, the Black-capped Chickadee has at least 16 distinct categories of vocalizations, most of them with multiple variations. But only one (or possibly two) of these could be classified as a song. All the rest would be best considered calls. So, yes, there are reasons to make a distinction between songs and calls.
How do we tell the difference? Songs are often longer and more complex than calls. Consider the American Robin. Its rich, caroling song—cheerup, cheerily, cheerup, cheerio, and so on—is quite different from any of its short, sharp calls. But songs don't have to be musical, at least not to human ears. The song of the Yellow-headed Blackbird is hardly melodic: The gaudy male perches up in the open and strains out a few raspy gurgles followed by a long, strangled buzzy noise. Definitely not top-10 material. The song of Henslow’s Sparrow is a brief, flat hslick, sounding almost one-syllabled. But the bird seems proud of it anyway, perching in damp meadows and singing it over and over, even all night on moonlit nights.
We can be sure that the short, simple performance of Henslow’s Sparrow is a song, not a call, because the difference is defined by function. In the avian world, a song has two main purposes: to defend a breeding territory, and to attract a mate. In the examples above—the caroling robin, the rasping blackbird, and the hiccupping sparrow—the singing individuals are perched in one spot, broadcasting their song to any other birds within earshot. The singing is a behavior unto itself, while calls are usually just accompanying other behavior.
Because of their purpose, songs are most typical during the breeding season. Species that defend territories year-round, however, may sing at any time of year. Even among some migratory birds, individuals may sing on the wintering grounds or during migration—perhaps for practice?—but with less consistency and vigor. In most species, the males take the lead in defending the territory, so it’s typically males that sing, though there’s a growing awareness that female birdsong is much more widespread and important than we used to think.
The habit of singing is not just limited to the so-called songbirds, of course; this behavior is found in many other groups—but not all. Birds as diverse as rails, nightjars, and trogons have songs that function in the classic way, to defend territories and attract mates. Many sandpipers and plovers perform flight songs on their Arctic breeding grounds, uttering trills or whistles as they flutter over the tundra. Male and female Pied-billed Grebes sing back and forth to each other to stay in contact and to defend the pair’s breeding territory, with a gobbling, cooing series that echoes through the marsh.
Although the song tends to be a bird’s most impressive vocalization, the calls, while simpler, can be surprisingly varied. Detailed studies of Northern Cardinals found that, in addition to their whistled songs, they have at least 16 different types of calls. A loud chip is by far the most familiar. Others are heard less often, such as various alarm calls, the begging calls of the young, or notes used by the male and female during stages of their courtship. Some rarely heard calls are used for very specific situations: The adult male reportedly calls pfft, pfft as he drives away fledglings that are old enough to forage for themselves. (I’ve never heard that call, but that must mean I haven’t paid enough attention to cardinals.) All of these calls may have different contexts and purposes, but none is a substitute for the song’s main role in maintaining the territory.
Now, while I’m describing the prevailing view of the difference between songs and calls, I should note that these definitions are not universally accepted. Some ornithologists dislike the term “song,” especially for species that aren’t among the classic songbirds of the order Passeriformes. Recently, I read a discussion of the deep oong-ka-choonk vocalization of the American Bittern, the distinctive sound that earns it nicknames like “thunder-pumper” and “stake driver.” The authors stated that this “call” seems to be used to defend the territory and attract a mate. In other words, it’s a call, in their judgment, that functions as a song; but they didn’t say that.
So you can expect to find some variation in how the terms are used. But keeping in mind the different functions of songs and calls will help you to understand what you hear from the avian choir.
Q: You once commented that good bird habitat and good birding habitat aren't necessarily the same thing. Can you explain?
KK: At first this might seem contradictory. Wouldn’t we always have our best birding in places where the birds themselves are most abundant and diverse? No, not always, and there’s a simple reason: access. We won’t have a satisfying experience if it’s too hard to get to where the birds are.
So, for example, a huge, marshy lake might be a paradise for water birds but completely inaccessible for birders. An extensive spruce bog might be perfect for various birds, but humans might find it impossible to walk through the bog to get to them. A dense lowland rainforest might host hundreds of species; but if there are no trails through the forest, and no roads or navigable rivers along its edge, it will be extremely difficult for birders to sample those avian treasures.
Purely from the standpoint of conservation, it might seem like the only important thing is to optimize the habitat for birds and other wildlife, not humans. From that perspective, any kind of access point for people would be considered a distraction from the main mission, diminishing the value of a protected site. I know that some individuals hold such views, and I can sympathize. If someone discovered a viable population of Ivory-billed Woodpeckers, for example, it would be fine with me if their entire habitat could be sealed off from roads, trails, or visitation; I’d gladly give up any chance of seeing them if that would help their survival.
It’s a careful balance to serve the needs of birds and people.
But except in such extreme cases, the reality is that birds need all the friends they can get—so it’s worth the effort to manage some areas of good bird habitat for both the feathered creatures and their observers. Promoting an interest in nature, making the introduction to birding as easy as possible, should (ideally) result in more support for conservation overall. For that reason, enlightened management of many wildlife areas includes the strategic placement of trails, boardwalks, observation towers, photo blinds, feeding stations, driving routes, and other enhancements for improved viewing opportunities. It’s a careful balance to serve the needs of birds and people.
When a new road or trail or tower goes into a previously wild area, animals may avoid it at first, thus effectively reducing the amount of usable habitat for them. But over time, something surprising often happens: The creatures become habituated to the presence of people, accustomed to being unharmed by the crowds, and relatively easy to observe. A good example of this phenomenon is Anhinga Trail, a paved walkway and boardwalk in Florida’s Everglades National Park. Popular and heavily visited for decades, it allows visitors of all abilities the chance to watch herons, egrets, ibises, Purple Gallinules, the namesake Anhingas, and numerous other birds foraging unconcernedly a few yards away. I’ve met people who told me that their interest in birding was sparked by those wonderful close-up views at Anhinga Trail. The remote back country of the Everglades is great bird habitat, the accessible Anhinga Trail is great birding habitat, and both are important and worth saving.