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 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 it just me, or are yellow Northern Cardinals becoming more common? I feel like more people are seeing them.
Kenn Kaufman: When the brilliant red of a male Northern Cardinal is replaced by brilliant yellow, the effect can be stunning for anyone accustomed to the bird’s normal appearance. Such variants do occur, but they are very rare.
Audubon featured a story about one such cardinal spotted in Alabama in 2018. At the time, birders consulted Geoffrey Hill from Auburn University, an expert on bird coloration, for insights on why this bird was yellow. Hill has since released a video discussing the science behind this variation. Basically, the red, orange, and yellow colors in birds’ feathers are created with carotenoid pigments derived from the foods they eat. In the male Northern Cardinal, yellow pigments from the diet apparently are converted to red by a specific enzyme. In a very rare genetic mutation, probably affecting fewer than one in a million cardinals, that enzyme is lacking, so the conversion to red doesn’t occur and the feathers are bright yellow instead.
During the last couple of years, we’ve seen reports of such yellow Northern Cardinals in Florida, Illinois, Tennessee, North Carolina, and elsewhere. But are such birds really occurring more often in the total cardinal population? Or are we just hearing about more of them? Although it’s impossible to be certain, I strongly suspect it’s the latter.
The first time I heard about a yellow cardinal, about 40 years ago, it was through a string of coincidences. Someone had seen such a bird at their feeder and mentioned it to a neighbor, and ultimately a local Audubon chapter newsletter carried a few lines about this odd bird. A friend of mine saw the note in the newsletter and happened to mention it to me. That was it. No photos, no press coverage, no media attention. And that was standard for odd birds at backyard feeders until very recently.
Today the world is connected like never before. Communication about birds had already ramped up considerably in the 1990s with the advent of birding listserves, and now it has multiplied many times over with the rise of social media. An unusual bird now can “go viral” if it captures the imagination of the public. That was what happened with the Alabama yellow cardinal in 2018. After Charlie Stephenson discovered the bird and Jeremy Black took superb photos, it became an internet sensation, with photos shared tens of thousands of times. Stephenson and Black even created a Facebook page celebrating this individual.
And as the fame of this cardinal spread, and the public became aware of its special status, other people started reporting that they had seen such birds as well. What would have merited a shrug and a “Hmm, that’s funny” in the past had now been anointed as worthy of note, worth sharing on social media.
Is there a conservation angle to this story? It’s always a good thing when people pay more attention to birds, of course. But the Northern Cardinal is one of the more abundant birds in North America. Its population has been estimated at more than 100 million, and stable or increasing. But there is a South American bird actually named the Yellow Cardinal (Gubernatrix cristata). It’s not at all related (it belongs to the tanager family), and far from being abundant, it’s considered an endangered species, with a population in the low thousands at best. Maybe we could figure out a way for fans of yellow cardinals in the U.S. to support conservation of Yellow Cardinals in South America.
Q: Why do birds imitate other birds and sounds? And why are certain birds such better mimics than others?
KK: Skill at imitating sounds is widespread among various groups of birds. Although the Northern Mockingbird is famed, and named, for this ability, it’s hardly the only mimic out there. Blue Jays can do a perfect rendition of a Red-tailed Hawk, and Steller’s Jays can nail the Red-shouldered Hawk. Lesser Goldfinches mimic parts of the songs of dozens of other birds; Lawrence’s Goldfinches might mimic fewer kinds of birds, but with higher quality imitations. A male European Starling can include imitations of more than 60 other bird species (and other sounds) in its repertoire.
Many species of parrots have an outstanding ability to copy human speech, but in the wild, they seem to use their mimicking powers mostly to imitate members of their own species, not other kinds of birds. On the other hand, some birds are virtuosos of copying everything within earshot. The Superb Lyrebird in Australia, for example, can perform highly accurate imitations of dozens of other bird species and of numerous other sounds—including, sadly, even the noise of chain saws destroying its habitat.
But my favorite mimic is Lawrence’s Thrush, a drab brown bird of the lowland rain forest in South America. At dawn in southeastern Peru, I have listened in awe as a Lawrence’s Thrush, hidden in the treetops, reeled off brief but perfect imitations of more than a dozen different birds in rapid succession. In the same region, the late Ted Parker once recorded a male that included imitations of no fewer than 51 bird species in a single continuous bout of singing.
These are extreme examples ,and most birds don’t make any sounds that we would recognize as mimicry. But the ability to hear a sound and copy it is actually very widespread among birds. In fact, it’s essential. Among the true songbirds, as well as parrots and hummingbirds, individuals have to learn their songs. Studies on many species suggest that they are born with a basic template for the song of their own kind, but unless they actually hear it, they will never learn to sing it correctly. So a certain level of copying is present, and even necessary, in a vast array of different birds.
The majority of these birds use this ability only to copy others of their own kind—faithfully claiming the vocal identity of their species, learning the local dialect, or matching songs with their neighbors. So why do a few species take it to a different level, appropriating songs from other birds and copying sounds from the environment?
Bird songs serve two main purposes: Defending territory and attracting (or maintaining contact with) a mate. An impressive song, like colorful plumage or fancy display postures, can serve as a way of signaling an individual’s fitness—fit to hold a territory against all rivals, fit to be an excellent mate. Of course, different species will have different instincts as to what constitutes an impressive song. For some, the size of the repertoire is key: The bird that can sing the most different songs will be perceived as superior. And what easier way to add to the playlist than simply copying any sound you hear?
Ultimately, however, we don’t know why this vocal behavior evolves in some species and not others. We might imagine that Lawrence’s Thrush developed great mimicry to make up for its plain appearance, but several related South American thrushes are equally dull-colored, and they don’t mimic sounds. We could guess that this behavior is tied to certain habitats, but excellent mimics are found everywhere, from dense rain forest to deserts. So far, no one has come up with a convincing common thread that would link all the great bird mimics of the world, and this would be an absorbing mystery for someone to solve in the future.
Have a bird or birding question for Kenn? Email it to firstname.lastname@example.org.