Meditations on mimics

By Kristen Lindquist | May 05, 2010
Photo by: Heather Gerquest

One recent morning as I was leaving for work I heard the distinctive call of a broad-winged hawk -- a piercing, high-pitched, two-tone whistle. The sound repeated several times. This was during the peak of broad-winged hawk migration, and I'd been looking forward to seeing my first one of the spring. Often in seasons past I've heard the call and stepped outside to see a broad-wing or two circling in the sky above Mount Battie. But the sky was empty today as far as I could see. Then it dawned on me: I was being duped by a blue jay.

And not for the first time. I've heard blue jays imitate broad-winged hawks, red-tailed hawks and ospreys. And this spring I heard a blue jay respond to the "beep-beep" of my car door opener more than once with a pitch-perfect imitation. A friend says she has heard a jay make a sound just like a sonar "ping." I'm not sure what the evolutionary advantage is to being such a successful mimic, but given that the blue jay's real specialty seems to be raptors, perhaps it's to mess with other birds, to scare them off a birdfeeder or their eggs or to otherwise distract them for some nefarious purpose of its own. Or perhaps it just enjoys playing with sounds. Jays are generally very verbal birds, possessing a canny intelligence. This one certainly played on my expectations that morning, as if it knew just what I was hoping to see and decided to tease me.

Two of our most formidable mimics, the gray catbird and the aptly named mockingbird, make their presence known this time of year. Both birds appropriately belong to the family Mimidae, and while their appearance may be plain -- both are relatively unmarked, gray birds -- their vocal talents are prodigious. On my annual May visit to Monhegan I have frequently heard catbirds singing, as it seemed, from every bush. During spring migration they seem to move through an area en masse. The catbird has shown up as a common species on my Beech Hill Preserve bird surveys, as well, singing in every shrubby corner. It gets its name from its call note, a whiny, cat-like "mew." Such a simple call belies the crazy intricacy of his song, which entwines strands of dozens of other birds' songs with improvised noises of his own.

A catbird can go on for 15 to 20 minutes at a stretch when so inspired. Thanks to the complexity and rapid change of phrase in his song, you never hear the same song twice. Even after coming across a dozen or more in the course of a day's birding, I'm never bored by the catbird, because I never know what's going to come out of his mouth. When listening to a catbird, or especially a mockingbird -- whose vocalizations are more distinct and reliably in sets of three to five -- it can be a fun challenge to try to pick out what birds are being imitated. With the mockingbird this test can be a special challenge because he knows many birds I don't. Once a fellow birder picked out the song of a buff-collared nightjar in a mockingbird's song. (I didn't know what that was, either.) And like my "beeping" backyard blue jay, he also imitates non-avian sounds -- car alarm, barking dog, squeaky wheel or whistling human.

The mockingbird's behavior and singing style reflect his brash personality. He readily swoops at those near his nest, flashing white wing-patches. And he sings loudly and long, sometimes into the wee hours of the night. A blast of nighttime birdsong might disturb some, but others, like vocalist Neko Case, find it soothing. In "Magpie to the Morning," she sings "Hear the mockingbird sing in the middle of the night. All of his songs are stolen ... Stole them from whip-poor-wills, screaming car alarms. He sings them for you special. He knows you're afraid of the dark."

Though not afraid of the dark, ornithologist Donald Kroodsma, who has studied birdsong for years, also appreciates the mockingbird's night singing. He has determined that the nocturnal soloists are as-yet unpaired males. Listening to one individual from midnight to 6:30 a.m., he estimated the bird knew about 100 different songs, from Carolina wren to phoebe to song sparrow. In his book "The Singing Life of Birds," he cites a Florida study in which some mockingbirds were found to have as many as 200 different songs. Another study indicates that birds seem to increase their song repertoire from one year to the next, learning more songs each successive year. Thus, a mockingbird that can show off a lot of different songs is an older and potentially more enduring mate.

As with me and my blue jay, Kroodsma was naturally led to wonder, "Why does a mockingbird mock?" He dismissed imitation as an easy way for the bird to expand its song base, because other species have many more songs on their internal playlist -- a catbird can have up to 400! In considering whether it's a warning to other species to stay away from either nest and/or feeding territory, he questions, "But why, then, a kingfisher rattle? Why a washing machine or a car siren, as other mockingbirds have been heard to sing? Is the mocker just hedging his bets by imitating broadly, making sure he has a song for all possible comers?"

Ultimately Kroodsma's theory is that the answer can be found in knowing what female mockingbirds really want. Something about the singing must resonate in a good way in the female's brain. And as for the male, Kroodsma adds, "I want to believe that he ‘enjoys' singing, that doing what he does so well satisfies some inner need for performing well." So if you're awakened by a mockingbird in the night, try to appreciate what you're hearing. Or if you can't, at least wish the bird well in finding a mate so he'll shut up soon.

Other birds act as mimics. Crows are well-known for imitating human sounds. And parrots, of course. The ubiquitous little starling has surprising vocal agility. I've had one wolf-whistle at me from a power line so convincingly that I was utterly confused when I turned around and no one was there. Was he, like so many guys on street corners, offering up his own misguided idea of "what women really want"? In any case, as with the blue jay in my yard, the many catbirds of spring, and the mockingbird down the street, he gained my appreciation for his imitative abilities. I bet he also had a little fun at my expense.

Kristen Lindquist is a published poet who works as the development director for Coastal Mountains Land Trust in Camden.

 


 

 

 

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