By John Hughes
Have you ever been walking in a riparian area and heard what sounded like a cat mewing in the thick understory? Every time this happens to my wife and me, we turn and look at each other, smile like kids, and say “catbird.” The Gray Catbird is one of many birds whose names are derived from their songs or call notes. In the case of the Gray Catbird, the mewing sound is a call note, and while it doesn’t really sound like a cat, barring perhaps a sick cat, it certainly reminds you of one.
The Gray Catbird is easily identified due to its coloration. Its overall slate gray appearance is not found in any other species. It has a black cap and tail with rufous-colored undertail coverts. For those familiar with its relative the Northern Mockingbird, they share a very similar profile. The Gray Catbird is 8.5 inches long with a wingspan of 11 inches, making it a bit smaller than the N. Mockingbird. Its wings are short and its tail is long; both are rounded in appearance.
The Gray Catbird is classified in the Order Passeriformes; Family Mimidae; Genus Dumetella; Species carolinenesis. There are 11 species in 4 genera in the United States found in the family Mimidae. With the Northern Mockingbird, Gray Catbirds share this family with the thrashers, most notably in Montana, the Brown Thrasher and Sage Thrasher.
Like many birds in the Family Mimidae, the Catbird has a large repertoire of songs and calls due to the structure of its syrinx (bird voice box). The syrinx is shaped like an upside-down Y located at the base of the trachea where it splits to form the bronchi. Membranes controlled by muscles vibrate to produce sound much the way human vocal cords do. Catbirds can produce sounds from the left and right side of the syrinx simultaneously, or use each side individually. This versatility produces a song described by David Sibley as “a rambling, halting warble with slow temp; distinctive mewing quality of low, hoarse notes with high, sharp chips and squeaks interspersed with little repetition and little mimicry.” Catbirds also use a Quiet Song, its normal song but lower in volume. The song is performed with the beak closed (or nearly so) during courtship, near the nest, or during territorial defense when an intruder is close. The Gray Catbird has three distinct call notes: the most common Mew Call, used year round during courtship, nest defense, and territorial chases; the Quirt Call, also used year round, which is a soft, low-pitched quirt, whurt, or quitt used as a low intensity alarm call and in flight during migration; and the Ratchet Call, also used year round, a high intensity alarm call (chek-chek-chek) used when chasing predators or intruders from a territory.
Dumetella means “dense thicket” and that’s where you will find the Gray Catbird. In Northwestern Montana, they are typically found in low-elevation, dense, shrubby riparian habitats. Flight is characterized by constant wing beats, and is typically short and low, just above the tops of shrubs or through small openings in the vegetation. They avoid flying across open spaces, traveling through shrubs using a combination of hops and short flights. They frequently flick their tails up and down and in a circular pattern.
Diet consists of insects and small fruits, shifting with the season, with fruits being more prevalent in fall and winter. They forage mainly on the ground using their beaks to knock leaf and ground litter aside in search of insects. They also forage in the vegetation, gleaning insects from leaves, and rarely will “fly catch.”
Courtship and breeding begins in early spring. Catbirds are monogamous and produce a three-layered bulky stick nest situated about 6 feet off the ground in the densest part of the vegetation. The female is mostly responsible for nest construction. Three or four turquoise green eggs are laid in the nest and incubated by the female. The male does not incubate eggs but occasionally brings food to the female. Both sexes take part in feeding the young and protecting the nest. Nest parasitism is attempted, primarily by Brown Cowbirds, but rarely successful. The Gray Catbird is one of only about a dozen species that can recognize an alien egg in its nest, an ability that is learned, not innate. Catbirds promptly remove Cowbird eggs from their nest, using their beaks to roll them from the nest or to skewer them. Breeding Bird Surveys conducted in the northeast indicate a decline in the number of breeding pairs while numbers of breeding pairs in other areas are stable or increasing.
In fall, Catbirds flock up and head for their wintering grounds in the southeastern United States and Neotropics. The majority of migration is at night. The Mew Call is given frequently during stopovers, especially during the early morning and at dusk. The Quirt Call is often used during flight, perhaps to maintain contact with fellow travelers. Migrants flying over the Gulf of Mexico often lay on extra fat to fuel them on their journey, while those migrating over land increase their lean body mass up to 150% for their trip.
My favorite places to observe Gray Catbirds are the shrubs along Tally Lake at the campground, and along the Stillwater River at Owen Sowerwine Natural Area. As the days get shorter and nights get longer, I look forward to spring when I will hear the familiar mew and smile and say, “CATBIRD!”