Extinct Birds Part 31

_Ocydromus dieffenbachi_ Gray, Voy. Ereb. and Terr., Birds p. 14, pl.

15 (1846).

_Hypotaenidia dieffenbachi_ Bonaparte, C. R. XLIII, p. 599 (1856).

_Cabalus dieffenbachi_ Sharpe, Voy. Ereb. and Terr., Birds p. 29, pl.

15 (1875), id., Cat. B. Brit. Mus. XXIII p. 47 (1894).

_Nesolimnas dieffenbachi_ Andrews, Novit. Zool. III. p. 266, pl. X, figs 3-15 (1896).

Adult: "General colour above, brown, banded on the mantle and scapulars, and spotted on the upper back with ochreous buff, these buff markings being margined with black, which takes the form of broad bars on the mantle; lower back and rump uniform brown; upper tail coverts brown, barred across with light rufous and black; lesser wing coverts like the back; median and greater coverts, as well as the primary coverts and quills, light chestnut, barred with black, the inner secondaries spotted and barred with ochre and black, like the back; tail feathers brown, mottled with chestnut near the base; crown of the head and nape uniform brown, followed by an indistinct patch of chestnut on the hindneck; lores dull rufous, surmounted by a broad line of bluish grey, extending from the base of the nostrils to the sides of the nape; rest of the sides of the face bluish grey, extending on to the lower throat; this grey area of the face separated from the grey eyebrow by a broad band of dark chestnut, which extends from the lores through the eye along the upper part of the ear-coverts; chin and upper throat white; lower throat black, barred across with white; fore neck and chest ochreous buff, banded rather narrowly with black, this pattern of colouration {126} extending up the sides of the neck to the chestnut on the ear coverts; lower breast and abdomen black, banded with white, the light bars on the flanks and vent feathers being tinged with ochreous; under-tail coverts broadly banded with black and ochre; under-wing coverts and axillaries blackish, barred with white; under surface of quills chestnut, with broad black bars.

Wing 4.8 inches, culmen 1.35, tail 2.7" (Sharpe).

Habitat: Chatham Islands.

The type and only known specimen is that in the British Museum.

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CABALUS HUTTON.

_Cabalus_ Hutton, Trans. N.Z. Inst. Vol. VI p. 108, pl. XX (1874--Type and unique species _Cabalus modestus_).

Captain Hutton characterized his new genus as follows: "Bill longer than the head, moderately slender and slightly curved, compressed in the middle and slightly expanding towards the tip; nostrils placed in a membranous groove which extends beyond the middle of the bill, openings exposed, oval, near the middle of the groove. Wings very short, rounded; quills soft, the outer webs as soft as the inner, fourth and fifth the longest, first nearly as long as the second; a short, compressed claw at the end of the thumb.

Tail very short and soft, hidden by the coverts. Tarsi moderate, shorter than the middle toe, flattened in front, and covered with transverse scales; toes long and slender, inner nearly as long as the outer, hind toe short, very slender, and placed on the inner side of the tarsus; claws short, compressed, blunt.

"The bird is incapable of flight, and the stomach of the specimen, dissected by Dr. Knox, contained only the legs and elytra of beetles."

Captain Hutton also adds, l.c., a valuable description of the skeleton.

One species known.

CABALUS MODESTUS (HUTTON).

(PLATE 28.)

_Rallus modestus_ Hutton, Ibis 1872, p. 247. (Mangare, Chatham Islands.)

_Cabalus modestus_ Hutton, Trans. New Zeal. Inst. VI p. 108. (The genus _Cabalus_ established.)

_Rallus dieffenbachii_ juv. Buller, B. New Zealand, Ed. I pp. 179, 180; Ed. II p. 121 (1888).

_Cabalus dieffenbachii_ (part., juv.!) Sharpe, Cat. B. Brit. Mus. XXIII p. 47 (1894); corr. p. 331.

_Cabalus modestus_ Forbes, Bull. Brit. Orn. Club. No. IV. p. XX (Dec.

1892); Salvadori, op. cit. V p. XXIII (Jan., 1893); Forbes, Ibis 1893, pp. 532, 544, pl. XIV, fig. 4, egg; Sharpe, Cat. B. Brit. Mus. XXIII p.

331 (1893); Buller, Suppl. B.N.Z. I p. 45, pl. III (1905).

_Ocydromus pygmaeus_ Forbes, Nature XLVI, p. 252 (1892--nomen nudum!

cf. Ibis 1893, p. 544).

Captain Hutton (Ibis 1872, p. 247) described this interesting species as follows: "Olivaceous brown, bases of the feathers plumbeous; feathers of the breast slightly tipped with pale fulvous, those of the abdomen and flanks with two narrow bars of the same colour; {128} throat dark grey, each feather slightly tipped with brown. Quills soft brown, the first three faintly barred with reddish fulvous, fourth and fifth the longest. Tail very soft and short, brown. Irides light brown, bill and legs light brown.

Length 8.75 inches, wing 3.15, bill from gape 1.4, tarsus 1, middle toe and claw 1.4.

_Young._ Uniform brownish black.

A single specimen and young from Mangare; also a specimen in spirits."

The author knew perfectly well what he was doing when he described this excellent species. Sir Walter Buller afterwards (B. New Zealand, Ed. I, pp.

179, 180) declared "after carefully comparing it with the type of _Rallus dieffenbachii_, and submitting the matter to the judgment of other competent ornithologists, I have no hesitation in considering it the same species, in an immature state of plumage." (_Sic!_) Unfortunately, Dr.

Sharpe, in the Catalogue of Birds XXIII, repeated Buller's error, and, on Plate VI, figured _Cabalus modestus_ under the name of _Cabalus dieffenbachii_, though the latter is not congeneric with _C. modestus_, and must be called _Nesolimnas dieffenbachii_, while the third form included in _Cabalus_ by Dr. Sharpe, viz. _sylvestris_ of Lord Howe's Island, must also be separated genetically from _Cabalus_.

Formerly _Cabalus modestus_ inhabited Great Chatham Island, as Dr. Forbes proved by bones found by himself at Warekauri, but when the species was discovered it existed there no more, though being plentiful on the little outlying island of Mangare. Unfortunately even there it is evidently extinct now, this island being overrun with cats and rats, besides which, according to Buller, the original vegetation has been ruthlessly burnt down for the purpose of sowing gra.s.s-seed, as even this bleak little island has been claimed by an enterprising sheep-farmer. Fortunately a good many specimens have been secured by the late W. Hawkins. I have fifteen in my museum, and there are specimens in the British Museum, in Liverpool, and one in Cambridge. Henry Palmer failed to get specimens when he visited Mangare.

I have also the egg described and figured in the Ibis by Dr. Forbes. It measures 40 by 21.4 mm., and is creamy white, with faint pale reddish and purplish roundish spots.

Habitat: Chatham Islands, east of New Zealand.

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OCYDROMUS MINOR HAMILTON.

_Ocydromus sp._ Hamilton, Trans. N.Z. Inst. XXV, p. 103 (1893).

_Ocydromus minor_ Hamilton (nec. Forbes) l.c.

This species is nearest allied to _sylvestris_ Scl., which has quite erroneously been placed in the genus _Cabalus_ by Dr. Sharpe; _sylvestris_ will have to form the type of a new genus, but until the skull of _minor_ is known I prefer to leave the latter temporarily in _Ocydromus_.

The present species is known from two pelves, seven femora, six tibiae, and five metatarsi, as well as the front portion of a sternum. The measurements all show that _minor_ was a slightly larger form than _sylvestris_, but owing to having a much shorter tibio-tarsus it must have been a much stumpier bird.

_Minor._ _Sylvestris._

Pelvis extreme length 65 mm. 62.5 mm.

Pelvis extreme breadth 28 " 25 "

Femur length 64 " 63 "

Tibio-tarsus length 93 " 98 "

Tarso-metatarsus length 53 " 51 "

Sternum greatest width 24.5 " 24.5 "

Habitat: Middle Island, New Zealand. Extinct.