Mimic Thrushes

(This 1051st Buffalo Sunday News column was first published on May 15, 2011.)

Northern Mockingbird photo by Glenn Clark

I'm finally seeing once again three bird species that continue among my favorites. The catbird, thrasher and mockingbird are members of the family Mimidae and they are often called mimic thrushes.

The catbird is, of course, the most common and more familiar of the three: it is slate-gray with a black crown and, hard to notice, russet under-tail coverts.

The mockingbird is also gray, but a much lighter gray than the catbird. It shows plenty of white in its belly, outer tail feathers and wing bars. Those wing bars flash into large white patches when it flies or displays.

With its brown back and brown-streaked breast, the brown thrasher looks to me like a robin-sized song sparrow.

Catbirds and thrashers arrived among the late April migrants. Mockingbirds are permanent residents. Most of the thrashers move on but right now all three are here and a day's birding usually finds each species.

When I was a youngster the thrasher was a common bird of the countryside, but today their numbers in our region have dropped significantly. On the state-wide June Breeding Bird Surveys they averaged five per count in 1965; today they average less than one. The brown thrasher is fast becoming a rare breeding species here.

That's the bad news. The mockingbird represents the good news. In their 1965 "Birds of the Niagara Frontier Region", Beardslee and Mitchell describe the mockingbird as very rare. With many other southern species - cardinal, titmouse, Carolina wren and red-bellied woodpecker - it has extended its range northward with warmer weather. Today it is rated an uncommon bird here at any time of the year.

What is it about these species that makes them the favorites of so many birders? It is certainly not their coloration. Tanagers and orioles and many other species put them to shame in that department. No, it is their singing that so attracts us. Their family is well named because, in addition to each of them having extensive repertoires, they are wonderful mimics.

And the three species are easy to tell apart by their songs. The catbird doesn't repeat, the thrasher calls in pairs, and the mockingbird says each phrase three times.

Thus, if you hear a bird singing without repetition a variety of songs from a hedgerow, often but now always including an occasional meouw, you probably have a catbird.

If, on the other hand, it is repeating each phrase - cheery-up cheery-up, tweedle tweedle, chip-a-chip chip-a-chip and so on - you have a thrasher.

And three or sometimes more times means mockingbird.

My wife's father, James Theodore (Theo) Copeland, a lifetime teetotaler, knew the mockingbird's song by a bit of doggerel, designed, I am sure, to shock his wife and daughters:

Theo, Theo, Theo,

Get dressed, get dressed, get dressed;

Go to town, go to town, go to town;

Get drunk, get drunk, get drunk;

Puke, puke, puke.

In his rich southern accents that line is drawled into pea-uke, pea-uke, pea-uke. And the verse ends:

Shame, shame, shame.

I can think of no more charming way to remember the mockingbird's thrice repeated phrasing, but no rhyme can convey the full repertoire of this versatile songster.

What acoustic engineers have found about the mockingbird has startled even these experienced scientists. Some of the mockingbird's copies are so close to the song of the bird it is imitating that electronic analysis cannot distinguish the copy from the original.

And the number is quite extraordinary. One was recorded by the Cornell Lab imitating 30 species. And here locally Willie D'Anna, Patrick O'Donnel, and Betsy Potter found one mimicking 27 species a few years ago. But the all-time record seems to have been established in 1924 when C. W. Townsend reported a mockingbird that mimicked 55 species in one hour!

Here is a sampling of the species these mimics have imitated:

Catbird: blue jay, flicker, tree frog and, of course, house cat.

Thrasher: phoebe, wood thrush, crested flycatcher and red-winged blackbird.

And the reining champion mockingbird (in many cases including many different songs and calls for each species): ruby-crowned kinglet, olive-backed thrush, black duck, pheasant, mourning dove, red-shouldered hawk and kestrel, cuckoos, kingfisher, whip-poor-will, towhee, jay, crow, starling, meadowlark, chipping and field sparrows, junco, towhee and rose-breasted grosbeak.