Mockingbirds are a group of New World passerine birds from the Mimidae family. They are best known for the habit of some species mimicking the songs of other birds and the sounds of insects and amphibians,^[1] often loudly and in rapid succession. There are about 17 species in three genera. These do not appear to form a monophyletic lineage: Mimus and Nesomimus are quite closely related; their closest living relatives appear to be some thrashers, such as the Sage Thrasher. Melanotis is more distinct; it seems to represent a very ancient basal lineage of Mimidae.^[2][3]

Species in taxonomic order

• Brown-backed Mockingbird, Mimus dorsalis
• Bahama Mockingbird, Mimus gundlachii
• Long-tailed Mockingbird, Mimus longicaudatus
• Patagonian Mockingbird, Mimus patagonicus
• Chilean Mockingbird, Mimus thenca
• White-banded Mockingbird, Mimus triurus
• Northern Mockingbird, Mimus polyglottos
• Socorro Mockingbird, Mimus graysoni
• Tropical Mockingbird, Mimus gilvus
• Chalk-browed Mockingbird, Mimus saturninus
• Hood Mockingbird, Mimus macdonaldi
• Galápagos Mockingbird, Mimus parvulus
• Floreana Mockingbird or Charles Mockingbird, Mimus trifasciatus
• San Cristóbal Mockingbird, Mimus melanotis
• Blue Mockingbird Melanotis caerulescens
• Blue-and-white Mockingbird Melanotis hypoleucus

Darwin and mockingbirds

The Chilean Mockingbird, Mimus thenca

When the survey voyage of HMS Beagle visited the Galápagos Islands in September to October 1835, the naturalist Charles Darwin noticed that the mockingbirds Mimus thenca differed from island to island, and were closely allied in appearance to mockingbirds on the South American mainland. Nearly a year later when writing up his notes on the return voyage he speculated that this, together with what he had been told about Galápagos tortoises, could undermine the doctrine of stability of species. This was his first recorded expression of his doubts about species being immutable, which led to him being convinced about the transmutation of species and hence evolution.^[4]

The mimids are the New World family of passerine birds, Mimidae, that includes thrashers, mockingbirds, tremblers, and the New World catbirds. As their name (Latin for "mimic") suggests, these birds are notable for their vocalization, especially some species' remarkable ability to mimic a wide variety of birds and other sounds heard outdoors.

Description

There are over 30 species of mimids in two larger and some 10 small or monotypic genera. They tend towards dull grays and browns in their appearance, though a few are black or blue-gray, and many have red, yellow, or white irises. They range from 20 to 33 centimetres in length, and 36 to 56 grams in weight.^[1] Many mimids have a rather thrush-like pattern: brown above, pale with dark streaks or spots below. They tend to have longer tails than thrushes (or the bigger wrens, which they also resemble) and longer bills that in many species curve downward (Clement & Perrins 2003).

They have long, strong legs (for passerines) with which many species hop through undergrowth searching for arthropods and fruits to eat. Their habitat varies from forest undergrowth to scrub, high-altitude grasslands, and deserts. The two tremblers live in the atypical habitat of rain forests in the Lesser Antilles, and the Brown Trembler has the particularly atypical behavior of foraging while clinging to tree trunks (Clement & Perrins 2003).

All known species build somewhat messy, bulky twig nests in dense growth, in most species on the ground or no more than 2 meters up. They usually lay 2 to 5 eggs that hatch in 12 or 13 days, which is also the length of time the chicks stay in the nest. Breeding usually starts in the spring or early in the rainy season, and many species can have two or even three broods per year. Most failures to fledge young are due to predation. Pairs often stay together for more than one breeding season (Clement & Perrins 2003).

In the history of science

This section requires expansion.

Contrary to often-held belief, the Nesomimus mockingbirds may have played at least as great a role as Darwin's finches in inspiring Darwin's work on his theory of evolution (Curry 2003).

Systematics

Outside the family

Phylogenetic analyses have shown that mimids are most closely related to starlings (Sibley & Monroe 1990, Zuccon et al. 2006). These and oxpeckers (and the Philippine creepers if they are not outright but highly apomorphic starlings) form a group of Muscicapoidea which originated probably in the Early Miocene - very roughly 25-20 mya^[2] - somewhere in East Asia (Zuccon et al. 2006). This is evidenced by the Asian-SW Pacific distribution of the most basal starlings (and Philippine creepers) and the North American range of the basal mimids.

They are sometimes united with the starlings in the Sturnidae as a tribe Mimini as proposed by Sibley & Monroe (1990). This makes the expanded Stunidae a rather noninformative group and is probably due to the methodological drawbacks of their DNA-DNA hybridization technique.

Within the family

The mockingbirds with some thrashers seem to form one major clade, while the two other groups and the remaining thrashers seem to form the another, but the basal branching pattern is not well resolved. The tremblers, again, are a monophyletic lineage. The latter, however, are embedded in a paraphyletic catbird-Caribbean thrasher assemblage which consists of many rather basal lineages.(Hunt et al. 2001, Barber et al. 2004)

For detailed information on the evolutionary relationships of the different mimid lineages, see their articles.

Mockingbirds:

• Genus Mimus - typical mockingbirds (some 10 species, includes Mimodes)
• The former genus Nesomimus, now part of Mimus^[3] - mockingbirds of the Galápagos Islands (4 species)
• Genus Melanotis - blue mockingbirds (2 species)

New World catbirds:

• Genus Dumetella - Gray Catbird
• Genus Melanoptila - Black Catbird

Thrashers:

• Genus Oreoscoptes - Sage Thrasher
• Genus Toxostoma - typical thrashers (11 species)
• Genus Ramphocinclus - White-breasted Thrasher
• Genus Allenia - Scaly-breasted Thrasher (formerly in Margarops)
• Genus Margarops - Pearly-eyed Thrasher

Tremblers

• Genus Cinclocerthia (2 species)

References

• Barber, Brian R.; Martínez-Gómez, Juan E. & Peterson, A. Townsend (2004): Systematic position of the Socorro mockingbird Mimodes graysoni. J. Avian Biol. 35: 195-198. doi:10.1111/j.0908-8857.2004.03233.x (HTML abstract)
• Clement; Peter; Perrins, Christopher (2003): Mockingbirds. In: Perrins, Christopher (ed.): The Firefly Encyclopedia of Birds: 534–535. Firefly Books. ISBN 1-55297-777-3
• Curry, Robert L. (2003): Darwin and the mockingbirds of Galápagos.
• Hunt, Jeffrey S.; Bermingham, Eldredge; & Ricklefs, Robert E. (2001): Molecular systematics and biogeography of Antillean thrashers, tremblers, and mockingbirds (Aves: Mimidae). Auk 118(1): 35–55. DOI:10.1642/0004-8038(2001)118[0035:MSABOA]2.0.CO;2 HTML fulltext without images
• Sibley, Charles Gald & Monroe, Burt L. Jr. (1990): Distribution and taxonomy of the birds of the world: A Study in Molecular Evolution. Yale University Press, New Haven, CT. ISBN 0-300-04969-2
• Zuccon, Dario; Cibois, Anne; Pasquet, Eric & Ericson, Per G.P. (2006): Nuclear and mitochondrial sequence data reveal the major lineages of starlings, mynas and related taxa. Molecular Phylogenetics and Evolution 41(2): 333-344. doi:10.1016/j.ympev.2006.05.007 (HTML abstract)

Footnotes

1. ^ McClure, H. Elliott (1991). Forshaw, Joseph. ed. Encyclopaedia of Animals: Birds. London: Merehurst Press. pp. 183–184. ISBN 1-85391-186-0. 
2. ^ The seemingly precise dates of Zuccon et al. are not based on material evidence but on a crude estimate; a general Early Miocene age agrees with the phylogeny of other Passeri however.
3. ^ American Ornithologists' Union, "Changes since 1 March 2005"

Thrashers are a New World group of passerine birds related to mockingbirds and New World catbirds. Like these, they are in the Mimidae family. There are 15 species in one large and 4 monotypic genera.

These do not form a clade but are a phenetic assemblage. It is rather likely than not — though by no means robustly supported — that the Sage Thrasher is a basal lineage among a group also consisting of mockingbirds and Toxostoma thrashers. The Caribbean thrashers occupy varying positions in an assemblage consisting of them, the tremblers, and the New World catbirds. Here, the White-breasted Thrasher appears to be quite basal though it is impossible to place it anywhere with certainty, whereas the Pearly-eyed Thrasher is probably quite close to the tremblers.(Hunt et al. 2001, Barber et al. 2004)

Their common name describes the behaviour of these birds when searching for food on the ground: they use their long bills to "thrash" through dirt or dead leaves. All of these birds eat insects and several species also eat berries.

Taxonomic list

Genus Oreoscoptes

• Sage Thrasher, Oreoscoptes montanus

Genus Toxostoma – typical thrashers

• Brown Thrasher, Toxostoma rufum
• Long-billed Thrasher, Toxostoma longirostre
• Cozumel Thrasher, Toxostoma guttatum – possibly extinct (2006?)
• Gray Thrasher, Toxostoma cinereum
• Bendire's Thrasher, Toxostoma bendirei
• Ocellated Thrasher, Toxostoma ocellatum
• Curve-billed Thrasher, Toxostoma curvirostre
• California Thrasher, Toxostoma redivivum
• Crissal Thrasher, Toxostoma crissale
• Le Conte's Thrasher, Toxostoma lecontei
• Vizcaino Thrasher, Toxostoma arenicola

Genus Ramphocinclus

• White-breasted Thrasher, Ramphocinclus brachyurus

Genus Allenia – formerly in Margarops

• Scaly-breasted Thrasher, Allenia fusca
  • Barbados Scaly-breasted Thrasher, Allenia fusca atlantica – extinct (c. 1990)

Genus Margarops

• Pearly-eyed Thrasher, Margarops fuscatus

References

• Barber, Brian R.; Martínez-Gómez, Juan E. & Peterson, A. Townsend (2004): Systematic position of the Socorro mockingbird Mimodes graysoni. J. Avian Biol. 35: 195-198. doi:10.1111/j.0908-8857.2004.03233.x (HTML abstract)

• Hunt, Jeffrey S.; Bermingham, Eldredge; & Ricklefs, Robert E. (2001): Molecular systematics and biogeography of Antillean thrashers, tremblers, and mockingbirds (Aves: Mimidae). Auk 118(1): 35–55. DOI:10.1642/0004-8038(2001)118[0035:MSABOA]2.0.CO;2 HTML fulltext without images