Ant Thrush And Bush-shrikes

23rd December 2010

  Picture of Ant Thrush (Thamnophilus)  This little bird, not so big as a Skylark, is very beautiful, notwithstanding its curious figure, with a disproportionately long bill, short tail, and strong legs, and absence of bright coloration, for the black, rich brown, sienna, buff, grey and white which its plumage presents, are most harmoniously contrasted or blended.  It is a native of the northern parts of South America, and Buffon received it from Cayenne through Manoncour, the little we know of its habits being due to the latter. 

It is a mark of Buffon's insight that he at once recognized in this species, and several others allied to it, obtained from the same source, a perfectly distinct group of birds which he designated Fourmiliers from their feeding (as he was told) chiefly on Ants (Mr. Bates (Nat. Amazon, ii. p. 357) says that the first signal given to the pedestrian of meeting with a train of Foraging Ants (Eciton) is the twittering and restless movement of small flocks of Ant-Thrushes in the forest, and that if he disregards their warning he is sure to be attacked by the ferocious insects). 
  
The systematists of Buffon's time (apart from Boddaert and Hermann), were perhaps not so perceptive, and referred these birds to the Thrushes or some of them to the Shrikes. Their distinctness was at last recognized, and they were duly regarded as forming a Family, Formicariidae, and by Mr. Sclater (Cat. B. Br. Mus. xv. pp. 176-328) in 1890, was divided into 3 subfamilies - Thamnophilinae, often known as "Bush-Shrikes," containing at that time 10 genera and at least 80 species; Formicariinae, the true Ant-Thrushes, including in them the Formicivorinae, by Swainson called "Ant-Wrens" (Zool. Journ. ii. p. 146), which Mr. Sclater had formerly recognized (P. Z. S. 1858, pp. 232-254) , and thus enlarging the Formicariinae so as to comprise 18 genera and more than 130, species; while the third subfamily Grallariinae included 5 genera and over 30, species.

Swainson did not know that his genus Formicivora had been anticipated by Temminck, who in 1807 (Cat. du Cab. p. 92) used the name Formicivorus, in a sense equivalent to Boddaert's Formicarius. The group separated by Swainson was called Eriodora by Gloger in 1827, which name therefore apparently ought really to have been adopted for it.

In reality but few of these birds have an outward resemblance to Shrikes, Thrushes, or Wrens, and all belong to quite a different division of Passeres.  In 1847 Johannes Muller and Professor Cabanis justly placed them among their Clamatores, and subsequently Garrod showed their Mesomyodian structure.

In modern times the Thamnophilidae have been separated off into a family of their own, whilst the Formicariidae family now contains a total of 7 Genera. Birds from both the Thamnophilidae and Formicariidae family are generally known as antbirds.

The Formicariidae are one of the most characteristic families of the Neotropical Region, abounding in the forest-districts of its middle portion, becoming less numerous in Central America, and still scarcer in the southern parts, only just reaching the plains of La Plata. They are mostly small birds of sober hue, some not bigger than Wrens; but members of the Genera Batara and Grallaria attain the stature of a Jay. The last named of them has much the appearance of a Pitta-a distinct group to which the name "Ant-Thrush" has also been applied. The Grallaria have very small tails and hop around in a thrush-like way.

The large family Thamnophilus, containing over 200 species, is one of the most important of the so-called "Bush-Shrikes", and many of its members are remarkable for the diversity in plumage between the two genders, that of the cocks being black or black banded with white, while that of the hens is rufous; but in some other groups the black or black-and-white plumage is common to both sexes.  Of this genus several species inhabit British Guiana, at least three occur in Trinidad, and at one in Tobago has been given the amusing name of the Qua-qua or Cata-bird (Ann. N H. xx. p. 331). Their presence in these two islands offers one of the many strong proofs of their fauna belonging to that of continental South America, since no member of the Family is found in the Antilles proper.

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