The Gray Catbird -July 2017
The Sound of Summer
by: Virginia Andrews
photography by: Virginia Andrews
It comes from the depths of every tangle, an emphatic call, a cry, almost a meow.
But the sound, whether sharp as in “Cat!” or drawled as in “CAAaaatt,” is from no stray feline. Skulking in the bushes, perched at the edge of a snarl of viney cover, a seemingly demure gray bird is guarding his nest.
Catbirds are in the bird family Mimidae, which includes Thrashers and Mockingbirds. But instead of two-part repeated phrases, Catbirds sing a long stream-of-consciousness monologue of sounds one after another: whistles, chucks, squeaks, grunts, chatter, pure notes, and of course, the familiar mewing that warns intruders.
Each Catbird has a double syrinx, or voicebox. These two structures can be used independently of each other and at the same time, making two sounds at once. A Catbird can harmonize, so to speak, with itself. Its monologue is more improvisational than musical. Never quite the same, it can go on uninterrupted for as long as 10 minutes at a time: “Awr, er, ah, deedle, eh, chuck, tweet, squeeeek, em, click, kerr, shriek, wheeze, chip, peep, hoo, doodle,” and so on. The sounds are a little like baby talk, or an ill-tuned orchestra of two. They sing most actively early and late, though they can be heard at any time, day or night. Sometimes the male and female sing a soft duet between branch and nest.
Catbirds also pick up and repeat other sounds in nature. Listen carefully and you can hear them discuss what the Blue Jay, Red-tailed Hawk, Yellow Warbler, Mourning Dove, Eastern Towhee or other birds said. They will also pick up human sounds nearby: the garbage truck, the car lock, part of a cell-phone tune. But the casual approach to a hidden nest produces that warning meow that is so familiar it is almost the sound of summer.
Gray Catbirds nest in large numbers on Nantucket in the summer. They are neotropical migrants. Most have come from warmer climes, from Florida through Central America or some Caribbean island. They stay low to the ground, rarely building above six feet. But by blending in with the shadows they are often overlooked. Black cap and tail, dark gray back, lighter gray underparts: this coloration gives them the perfect camouflage for life on the Grey Lady.
They utilize dense vegetation along roadside edges or lawns. They are one of the most numerous of Massachusetts birds, occupying 98 percent of the Bay State. They don’t mind people. They have adapted to suburban landscapes. Apparently they survive the depredations of roaming domestic cats, and without raccoons, foxes, coyotes or other mainland predators, they have more sanctuary on Nantucket than in some other places.
Although doing well in New England, they have declined overall in the East and Southeast. But here at least they are literally sitting in the Catbird seat. Sitting pretty, that is: secure in their position.
One key to their abundance may be that Catbirds have learned to distinguish the eggs of the Brown-headed Cowbird from their own. Cowbirds are brood parasites. They lay their eggs in other birds’ nests, leaving their offspring to be raised by the unsuspecting parents. Pity the poor warbler that engages in a never-ending struggle to stuff food in the mouth of a cowbird chick twice its size.
Barely able to reach up to junior’s mouth, the unwitting host never seems to realize its own young have been murdered by the interloper, either in the egg or as nestlings. Cowbirds are specialists in what is known as “edge” habitat. They originally followed the great herds of bison across the plains. As the beasts were nomadic, it made sense for the birds to leave their young for others. But as development moved west, cowbirds moved east. With the demise of the buffalo and the rise of first agriculture and then suburbia, this type of habitat burgeoned. So did the Cowbirds.
Birds which fail to recognize alien eggs have a harder time surviving, as their reproductive energy goes to another species. Although the causes of loss are many, a large number of our songbirds have suffered from this type of predation. But for the canny Catbird, not so much. Without an innate sense the Catbird has nonetheless learned to recognize and destroy the eggs of this parasite
when they appear in its nest. They may poke a hole, push it out, or simply abandon the contaminated nest and build a new one somewhere else. This ensures that all their energy goes to feeding and raising their own young.
Like most birds, Catbirds consume and feed their young many insects: moths, caterpillars, spiders, the ant as well as the grasshopper, even beetles. But they also like fruit: shad, blueberries, mulberries, hollies, cherries and elderberries.
In the garden they can be a pest, even when consuming other garden pests. They like raspberries and blackberries, and they seem to have an ever-optimistic attitude about fruits they don’t seem to actually like but forever want to try, just in case. This is evidenced in the holes poked in nearly (but not quite) ripe tomatoes. It is as if the bird asked itself, “Would I like this?” “No.” “How about this one?” “No.” “This one?” “No.” “This...?” “No.” They can eat other seemingly
less digestible comestibles: the hard, dry fruit of multiflora roses, Oriental bittersweet, even poison ivy.
But this ability to eat many different foods enables some Catbirds to winter over even as far north as Nantucket. In a mild winter they can be found in protected spots, such as Lily Pond, or the small pocket marsh behind the Shipwreck & Lifesaving Museum.
Banding records have also shown them to be long-lived. The oldest on record was over 17 years of age. They are usually quite silent in winter, unless the sun warms them with a promise of spring, and then they may start to tune up, getting ready for another long summer of singing their kind of talking jazz. ///
Virginia Andrews writes the weekly “Island Bird Sightings” column for The Inquirer and Mirror and is a regular feature writer for Nantucket Today.