THRASHERS & MIMIDSMimidae The Mimids are a New World family composed of the thrashers, the mockingbirds, and the New World catbirds. They are particularly known for their vocalizations, many of which include fantastic mimicry of other birds and outdoor sounds (thus "mimids" for mimickers). There is almost nothing so joyful as the song of a California Thrasher (left) in an early spring morning among fragrant California chaparral. This particular bird was in full song at the moment this shot was taken, yet the bill is barely open! Pouring out were dead-on replications of flickers, kestrels, wrentits, and many other sounds, but they appeared effortless. What a contrast to, say, a Grasshopper Sparrow which puts its full heart and wide-open beak into his spring song -- a tuneless barely audible buzz!

Except when perched up and singing, the California Thrasher and many others in this family are very difficult to see as they skulk in the undergrowth. The abundant eastern North American Gray Catbird (right) is a skulker, but can sometimes be more easily seen in migration or its wintering grounds (as here in the Florida everglades). It, too, has a complex fluty song but it is named for its mewing call note. Almost all the thrashers (except the Mockingbirds which we'll discuss next) prefer dense thickets and undergrowth, making them difficult to locate (the same can also be said for mockingbirds in the genus Melanotis -- the Blue M. caerulescens & Blue-and-white M. hypoleucus mockingbirds of Mexico).

While thrashers and catbirds have wonderful vocalizations, perhaps the best known of all the mimids are the mockingbirds. There are 16 species called "mockingbirds" but it is the nine of these in the genus Mimus that are best known for their songs. The Bahama Mockingbird (left) is restricted to arid scrub in the Bahamas & Jamaica, but our Northern Mockingbird M. polyglottos is widespread in the southern U.S. Its Latin name translates to "many-throated mimic" and its song is a constant sound in lightly-wooded open country in the spring (suburbs to magnolia gardens to southwestern deserts). With the opening of California to human development, Northern Mockingbirds spread north throughout the Central Valley and into the Bay Area by the mid-1900s (Arnold 1980) and they have now reached the far northwest in the state.

Some mockingbirds sing all night long -- numerous complaints from insomniacs -- and aggressively defend their nest-sites from hawks, jays, cats, dogs and unwary people! This bird is such a fine mimic that one can often determine what other species are around by identifying each rendition. I recall a time some years back when I first recognized a crossbill invasion was starting because the local mockingbird starting incorporated the "kip" notes of Red Crossbills! Bent (1948) quotes T. Gilbert Pearson who wrote that the mockingbird "revels in the glory of his vocal strength, and shouts his ringing challenge to the tree, the flowers, the very sky itself... However, it is at night that the Mockingbird is at this best. If he is the music-prince of the grove by day, he is the song-king of the lawn on moonlight nights!"

Four species of mockingbirds are in the genus Nesomimus and are restricted to the Galapagos Islands. This is the more widespread Galapagos Mockingbird (right), but the three others are endemic to one or two tiny islets each. These Galapagos birds are extremely unwary and bold, eagerly checking out humans for potential tidbits and sometimes landing on camera lens or boots! Given this behavior, several species have suffered from the introduction of non-native predators (rats, cats) and special efforts are underway to save some species from extinction.

Another cool thing about some of the northern mimids is their migration, which leads to navigation errors and vagrants. Eastern North American species such as the Gray Catbird or Brown Thrasher Toxostoma rufum occasionally turn up in California, where I live, and the widespread Great Basin species -- the Sage Thrasher (below) -- sometimes makes it to the coast in fall or winter. The young bird photographed below was hanging out among farm equipment and a fenceline at a local sewer pond...

Since mimids are New World species, and nearly all of them are found in North & Central America, I've done pretty well in finding a good selection. I recall that when I first started birding enthusiastically as a college freshman, I really craved a trip to Arizona to search for the fine thrashers shown in my Golden Guide field guide: Curve-billed T. curvirostre, Bendire's T. bendirei, LeConte's T. lecontei, and Crissal T. crissale. Today, of course, I've had many experiences with these species and now revel in successful efforts for such specialties as Ocellated Thrasher T. ocellatum (restricted to oak-pine highlands in or near the state of Oaxaca, Mexico) or the Cozumel Thrasher T. guttatum (endemic to Cozumel I. off the Yucatan Peninsula, Mexico) or the endangered White-breasted Thrasher Ramphocinclus brachyurus (found only on the Lesser Antillean islands of St. Lucia and Martinique). Two other localized species are shown below: the Black Catbird (below left) -- restricted to coastal Yucatan Pen. & Cozumel Island -- and the Pearly-eyed Thrasher (below right) of the Caribbean (found from s. Bahamas/Hispaniola to the Lesser Antilles). The latter species seems to fill the "jay" niche in the Caribbean, being omnivorous (look at that bill!) and searching out other bird's nests for eggs or fledglings.

It was in the Caribbean islands of St. Lucia, St. Vincent, and Dominica that I encountered perhaps the strangest thrashers of all -- the two species of tremblers. This is the Brown Trembler (left), striking a characteristic stance with cocked tail. I had expected to find them in the undergrowth, like other thrashers, but these are arboreal specialists. They use their long thin bills to probe bromeliads and leaf-clusters in the canopy. The Brown Trembler prefers wet rain forest; the Gray Trembler Cinclocerthia gutturalis of St. Lucia & Martinique also extends into dryer woods. Both have the very odd habit of quivering their wings while at a perch -- "trembling" as it were -- but otherwise remaining remarkably unobtrusive. Their arboreal, probing activities reminded me of some long-billed foliage-gleaners in South America, but their trembling behavior was altogether unique. I really thought there was no way I'd get a photo of these canopy dwellers, but a pair was nest-building in the eaves at the entrance station/cafe at the "Emerald Pool" on Dominica, and I noted the birds used the same perch to fly to and from the hidden nest site. So I upturned a restaurant chair to use as a tripod and managed a few shots. The birds were entirely oblivious to hordes of tourists, brought by vans from their cruise ships, pouring into the entrance booth or eating at the cafe just below their nest.

The taxonomic relationships of the Mimidae are comparatively settled. They are biochemically related to starlings, and Sibley & Monroe (1990) emphasized this by placing them simply as a "tribe" among the starling family (Sturnidae). Morphological analysis confirms a closer relationship to starlings than to thrushes & allies (Beecher et al. 1953). The 7th ed. A.O.U. Check-list (1998), quite properly, place these distinctive birds in their own family but next to starlings. All authorities now appear to agree that there are 34 biological species among the mimids.

Photos: The California ThrasherToxostoma  redivivum was singing in chaparral at Ft. Ord, Monterey County, California, on 29 Dec 1994. The Gray Catbird  Dumetella carolinensis was in Everglades Nat'l Park, Florida, on 8 Jan 1999. The Bahama Mockingbird  Mimus  gundlachii was on San Salvador I., Bahamas, on 18 May 1983. The Galapagos Mockingbird  Nesomimus parvulus was on Santa Cruz I., Galapagos, on 25 Sep 1989. The Sage Thrasher  Oreoscoptes montanus was a vagrant to Salinas, Monterey County, California, on 14 Oct 1996. The Black Catbird  Melanoptila glabrirostris was on Cozumel I., Mexico, on 2 Sep 1979. The Pearly-eyed Thrasher  Margarops fuscatus was on the prowl at Cinnamon Bay, St. John I., U.S. Virgin Is., on 28 Aug 1979. The Brown TremblerCinclocerthia ruficauda was at the entrance to the "Emerald Pool" in the central highlands of Dominica on 24 Mar 2000. All photos © 2000 Don Roberson; all rights reserved.

Bibliographic note:

There is no "family book" of which I'm aware, so I gleaned information from Bent (1948) and my own experiences (some mentioned in Roberson & Tenney 1993). The Handbook of the Birds of the World series has not reached this family, but one suspects it will provide an outstanding overview in due course. An outstanding set of tapes of all the thrashers & mimids of the world is Hardy et al. (1987).

Literature cited:

American Ornithologists' Union. 1998. Check-list of North American Birds, 7th ed. A.O.U., Washington, D.C.

Arnold, J. R. 1980. Distribution of the mockingbird in California. West. Birds 11: 97-102.

Beecher, W. J. 1953. A phylogeny of the oscines. Auk 70: 270-333.

Bent, A. C. 1948. Life histories of North American nuthatches, wrens, thrashers, and their allies. U. S. Nat. Mus. Bull. 195. Smithsonian Instit., Washington, D. C.

Hardy, J. W., Jr., J. C. Barlow, and B. B. Coffey, Jr. 1987. Voices of all the Mockingbirds, Thrashers & their Allies: Family Mimidae. Cassette tape. ARA records, Gainesville, FL.

Roberson, D., and C. Tenney, eds. 1993. Atlas of the Breeding Birds of Monterey County, California. Monterey Pen. Audubon Soc., Carmel.

Sibley, C. G., and B. L. Monroe, Jr. 1990. Distribution and Taxonomy of Birds of the World. Yale Univ. Press, New Haven, CT.




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