The northern cardinal, crimson and crested, is an avian icon, one of the most recognizable birds on the continent. But the rosebreasted grosbeak is also a cardinal. So is the scarlet tanager. Even the indigo bunting is a cardinal. And you thought you knew cardinals.
Each of those birds belongs to the Cardinalidae, the cardinal family. In life and in science there is harmony in families. Their member species share certain characteristics. For birdwatchers, the family and its features can be a sunny path to bird identification.
Color isn’t necessarily one of those family traits. Consider our cardinals. A bird need not be red to be a cardinal. The same goes for blackbirds, in the family Icteridae. The Baltimore oriole is a blackbird. So is the eastern meadowlark.
Size doesn’t always help either. The blue jay and the common raven belong to the same family, the Corvidae.
Shape? Not always. The greater roadrunner, a gangly, longlegged ground bird, is actually a cuckoo in the family Cuculidae, the majority of which are slender, tree-dwelling birds.
How about vocalization? Nope, sorry. The songs of different warbler species, in the family Parulidae, vary from buzzy to melodious.
So by now you’re asking, “Where’s the harmony? Why bother?”
Stay with me.
In many cases harmony comes from within. Biologists who organize birds into families often rely on skeletal structure, muscle shape, or the shape of internal organs, such as a bird’s voice box (the syrinx), to bring order to the diversity.
Sometimes the harmony is subtle – and visible. Check out the bills on the northern cardinal and rose-breasted grosbeak. Thick and heavy. Those are cardinal bills. Now look at the daggers on the Baltimore oriole and boat-tailed grackle. Those are blackbird bills.
So for some family traits, a naturalist need only know where to look. A towering black locust is no less a member of the pea family (Fabaceae) than the sugar snap creeping in your garden. Their flowers are alike. Harmony resides in those flowers.
And sometimes the family can be a birdwatcher’s friend in the field. Consider the flycatchers (Tyrannidae) and the vireos (Vireonidae). Beginning birders often struggle to distinguish these two groups. Many flycatchers, and all vireos, are small, drab olive-gray, and subtle in their field marks.
But harmony prevails in each family.
Flycatchers share a shape and posture. They have relatively big heads that seem to be squished down onto broad shoulders. Their pose is upright. Their feeding style is distinctive: they launch from a perch, snatch an insect mid-air, and return to the perch to complete the meal.
Vireos differ in so many ways. Their heads merge into a short, stout neck. They lean forward in their posture. And vireos are gleaners when feeding: they hop sluggishly among tree leaves grabbing insects, mostly small caterpillars, along the way.
Seeing these kinds of family traits is no different than being away from your home woods and encountering a tree with thin twigs, opposite branching, and a familiar leaf. “I don’t know this tree species,” you may say to yourself, “but I’m certain it’s a maple” (in the family Aceraceae).
Do recognize that the taxonomy of birds (and other groups) can be in hot dispute and flux. Biologists now work at the molecular level, using DNA sequences, to determine the evolutionary relationships among organisms. It’s what recently brought our tanagers, for example, into the cardinal family.
Yet for our purposes, at least for now, a flycatcher will always be a flycatcher and a vireo a vireo. As you learn family features, subtlety wanes. Vireos and flycatchers become as distinctive as, say, warblers and woodpeckers. So, in the field, when you encounter some drab olive-gray bird perched upright, you may say to yourself. “I don’t know this bird, but I do know that it is a flycatcher.” From there you will know where to turn in your field guide.
That’s what I call family values.
Bryan Pfeiffer is an author, wildlife photographer, guide, and consulting naturalist who specializes in birds and insects. He lives in Montpelier, Vermont.