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A History of the Birds of New Zealand.

Phalacrocorax Brevirostris. — (White-Throated Shag.)

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Phalacrocorax Brevirostris.
(White-Throated Shag.)

  • Phalacrocorax brevirostris, Gould, P. Z. S. 1837, p. 26.

  • Graclus brevirostris, Gray, Voy. Ereb. and Terror, Birds, p. 20 (1844).

  • Carbo flavagula, Peale, U. S. Expl. Exp. p. 270 (1848).

  • Halieus brevirostris, Bonap. C. R. xliii. p 577 (1856).

  • Microcarbo brevirostris, Bonap. Consp. Av. ii, p. 178 (1857).

  • Carbo brevirostris, Cass. U. S. Expl. Exp. p. 375 (1858).

  • Phalacrocorax finschi, Sharpe, App. Voy. Ereb. and Terr. p. 35 (1875).

Native name.—Kawau-paka.

Ad. suprà nitenti-niger, interscapulli plumis medialiter sordidè cinerascentibus: scapularibus et tectricibus alarum cincrascentibus conspicuè velutino-nigro marginatis: remigibus et rectricibus nigris, canescente paullò lavatis: frontis nuchæque plumis elongatis, loris cum supercilio distincto, facie laterali guttureque toto albis: subtùs nitenti-niger: rostro flavicante, culmine et apice brunnescentibus: pedibus nigris: iride saturatè brunneè.

Juv. omninè nitenti-niger: pileo et collo postico brunneo lavatis: gutture et facie laterali paullò cinerascentibus: tectricibus alarum minimis brunneo marginatis.

Adult. General plumage glosay black, slightly tinged with green on the upper surface; a line of white extends from the nostrils over the eyes, and, spreading into a patch beyond, covers the cheeks, throat, and a large portion of the fore neck, often varying, however, in extent in different examples; wing-coverts and scapulars shining greyish black, bordered with satiny black; quills and tail-feathers black, with polished shafts. Irides deep chocolate-brown; naked skin in front of the eyes and bordering the pouch greenish yellow; bill bright yellow, changing to black on the ridge and towards the hook; legs and feet black. Total length 24 inches; extent of wings 34; wing, from flexure, 9·5; tail 7·5; bill, along the ridge 1·5, along the edge of lower mandible 2·4; tarsus 1·25; longest toe and claw 3.

Obs. Some specimens exhibit a few short filamentous white feathers on the posterior sides of the head.

I have an adult bird exhibiting a seasonal change of plumage from a rusty or brownish black to the glossy black, and without any indication of white on the throat or fore neck. This specimen would seem to favour the view held by some collectors that there is a small Black Shag in New Zealand distinct from P. brevirostris. For the present, however, we must treat it as a melanoid variety of the common species. In some examples of this bird there is a tendency in the underparts to change to white, and as a rule the extent of white on the throat and fore neck is uncertain and variable. On this account Dr. Finsch seems inclined to unite the species with P. melanoleucus (Trans. N.-Z. Inst. v. p. 211). But I have never seen a specimen exhibiting the “frill” or lateral and occipital crcata which are characteristic of the last-named species. Birds in full nuptial plumage have the feathers of the vertex lengthened, so as to form a slight crest.

Young. Entire plumage glossy black, inclining sometimes to greyish white towards the base of lower mandible; sides of the head, fore neck, and breast tinged with brown; mantle and upper wing-coverts greyish black, with velvety borders and brownish tips. The bill has the upper mandible dark brown, with yellow edges and tip, the lower mandible bright yellow, with wavy brown marks in the centre; legs and feet jet-black. Bare membrane around the eyes and at base of lower mandible flesh-colour.

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Nestling. Covered with thick down of a jet-black colour; forehead and fore part of crown and a broad space round the eyes and across the chin perfectly bare and of a pale blue, changing to purplish flesh-colour towards the base of lower mandible. The feathers come first on the back and flanks, the quills and tail-feathers also making an early appearance. The newly-hatched chick is almost wholly bare; and in its next state it is sparsely covered with short, smoky-grey down, looking as if it had been singed in the fire, the head and neck being still bare and resembling the leather of a black kid glove. Down the abdomen there is a line of white which widens out near the vent.

Fledgling. The fully-fledged nestling is all black, but, in some specimens, immediately below the gular sac, which is greenish yellow, there are a few narrow white feathers interspersed among the black.

Varieties. Although the plumage described above is undoubtedly that of the adult, this species appears to exhibit a dimorphic phase. In almost every flock (say of a dozen) a bird will be observed having the throat, fore neck, and entire under surface pure white. Between this extreme form and the normal white-throated bird every intermediate condition of plumage may from time to time be met with, although the vast majority of these birds have merely white throats. My series presents the following gradation:—

No. 1. Entirely black (young bird).

No. 2. White-throated as described above (both sexes alike).

No. 3. The white extends down the fore neck and terminates sharply on the crop.

No. 4. The white extends further and is mixed irregularly with the black on the breast, the former preponderating.

No. 5. Has the abdomen also largely marked with white.

No. 6. Has the entire under surface white with a few widely scattered black feathers.

No. 7. Has the well-defined black and white plumage, as described above.

I think it is the safest course to account for this variation on the theory of dimorphism, because the two forms interbreed; whilst, as fixing the normal plumage, I may mention that on visiting one of their nesting-colonies I found the breeding-birds (of both sexes) in the ordinary white-throated plumage, without a single exception.

A specimen in the British Museum, with a very white throat, has the plumage of the underparts largely tipped with pale brown.

Mr. Sharpe’s P. finschi is undoubtedly only an albinoid form of P. brevirostris. I have examined his type in the British Museum, which was in the collection of New-Zealand birds brought home by the Antarctic Expedition. It is in the pied plumage described above, with the following differences:—The frontal feathers, which are somewhat lengthened, are pure white; on each wing there is a large subtriangular patch of white, covering the median coverts; the white is pretty even on both wings, but on one of them it extends to the outer web of one of the longer coverts, and there is likewise a white feather among the scapulars, thus betraying the albinism. But what places the matter beyond all doubt is the existence of another example in the British Museum, more recently received from Wellington, in which the white markings are considerably extended. In this example the white alar patch is again present, although appreciably larger in one wing than the other; the scapulars on both sides are almost entirely white, so also is the middle portion of the back, whilst there are numerous white feathers scattered through the black plumage covering the shoulders; on the crown the black is reduced to a small irregular patch, whilst on the nape there is a disconnected stripe of black, the rest of the neck being pure white. It is apparent, at a glance, that this is a case of albinism; and by labelling this also P. finschi, Mr. Sharpe practically admits that his supposed new species will not stand.

Another example of the pied form in the British-Museum collection has the feathers covering the shoulders and the median upper wing-coverts narrowly margined with brownish white, outside the velvet border, imparting a lively effect to the plumage of the upper surface.

Note. At Whakatane, in the month of January, 1886, I saw a flock of seven, five of which were in the ordinary white-throated state. Of the remaining two, one was entirely black, the other had white underparts and a conspicuous spot of white on each wing. This at once raised a doubt in my mind (now confirmed) as to the specific value of the bird referred to by myself in the following note:— “Mr. W. T. L. Travers, who has page 170 just returned from the Hot Springs, informs me that, in Lake Tarawera, he observed a small Shag, differing apparently from P. brevirostris, being of inferior size and marked with white on the wings. He was unable to obtain a very close inspection, but it seems not unlikely that this is the bird described by Mr. Sharpe under the name of P. finschi.” (Trans. N.-Z. Inst. vol. ix. p. 336.)

The White-throated Shag, which appears to be confined to New Zealand and the Chatham Islands, frequents the freshwater rivers and lagoons in all parts of the country. Like some of its congeners it is social or gregarious, obtains its subsistence by diving, and roosts at night on the branches of trees overhanging the water. Its food consists chiefly of eels and small fish; but I have also found the stomach filled with freshwater shrimps.

It has a habit of swimming, for a yard or two at a time, with its head just under the surface as if foraging for food under water.

It is met with more or less on all parts of the coast, but there are some localities which it specially affects. One of these is the Porirua harbour near Wellington. Latterly the progress of the Wellington and Manawatu railway-works has interfered with the quietude of the place, but for nearly thirty years past I have been accustomed to see them when riding or driving along that road. They congregate at the little rocky points, in parties of three or four, and sometimes from 15 to 20— some sitting bolt upright, others with their “banners unfurled,” and others preening their feathers in the sunshine. The white throat is very conspicuous as the bird turns its head from side to side, and the occasional presence of a white-vested individual among those wearing the black livery always has a picturesque effect.

It is very strong on the wing, and often ascends to a considerable height in the air, and then sails in wide circles. On these occasions, owing to its narrowness of body and length of neck and tail, it has very much the appearance, when seen from below, of a flying cross.

It is active in all its movements and often exhibits an unusual amount of intelligence amounting almost to ratiocination. For example: I remember once standing on the bank of the Waikato river, near the Aniwaniwa rapids—at the point where the stream is so narrow that in ancient times a war-party bridged it with a fallen tree—when I observed one of these little Shags rise from the water and take its silent course up the stream, skimming low along the surface. It passed a little jutting rock, suggestive of a Shag station, and after proceeding some yards further seemed to change its mind, dropped suddenly into the water, deliberately swam back, and mounted the stone, where it remained some time sunning its outstretched wings.

I have remarked that it has a special fondness for waterfalls and loves to disport itself in the vapoury spray. On the 23rd of October I paid a visit (by no means the first) to the Huka Falls, near Taupo, one of the finest sights of its kind in all the Southern Hemisphere. Here the whole volume of the Waikato river (after a course of fifty miles from its source in the Ruapehu mountains), confined within stone walls scarcely thirty feet apart and forming as it were an immense sluice-box, comes plunging down the steep channel with terrific velocity till it shoots over a precipice of forty feet in a magnificent cascade, discharging about 240 million gallons of water every hour into a basin of seething foam. Nothing can be more beautiful or picturesque than the view which is obtained of this unique waterfall from below, on the Wairakei side of the river. The fine spray caused by the madly plunging volume rises in a vapoury mist high above the basin, and the slanting rays of the sun upon this produces ever-changing rainbows of exquisite beauty. Descending the bank, I entered the little rocky cavern known as Ethel’s cave*, the arched roof of which is densely covered with, Lomaria, Adiantum, and other hanging ferns of great beauty, whilst the entrance is protected and page 171 shaded by a group of luxuriant tree-ferns (Dicksonia squarrosa) growing up from the very edge of the water, their fronds almost interlaced by their close contact and their stems laden with the withered growth of a former season, hanging around them like a well-wrapped Maori toga. Seated in this cool and enchanting spot, and listening to the delicious song of the Zosterops, I gazed long and with insatiable delight on the Huka Falls; and not the least interesting feature to me was this, that a dozen or more of these little Shags (or “River Crows” as they are sometimes called) kept passing and repassing through the misty spray, and up and down the surging “sluice-box,” apparently for the sheer delight of the thing, or else in silent wonderment.

On another occasion I was standing, with a party of tourists, admiring the beauties of the Wairere waterfall near the Taheke. In this unique fall the whole volume of water plunges over two ledges in succession, increasing its velocity at the lower one, and forming in the stream below a swirl of considerable force. And the effect is greatly heightened by the peculiar situation of the waterfall, both sides being closed in by dense overhanging woods, the undergrowth being so luxuriant that the pendent ferns dip their waving fronds in foaming water. While standing at the very edge of the lower bank, holding on to a convenient branch and gazing on the beautiful scene, a White-throated Shag swept past us, within a yard or two, and, passing the fall, disappeared in the woods beyond. I mention this in illustration of the habits of this bird, which seems to be quite as much at home in woodland stream as on the sea-shore.

Dr. Finsch says (Trans. N.-Z. Inst. vol. vii. p. 235):—“Although omitted in Dr. Buller’s work there can be no doubt that Mr. Peale collected a Shag in the Bay of Islands, which, like Graucalus chalconotus, Gray, has not yet been observed since. This species, G. purpuragula, Peale, seems to be very near if not identical with G. stictocephalus, Bp.=sulcirostris, Brandt.”

I still omit Phalacrocorax purpuragula from our list, because I feel persuaded that Peale’s specimen was only P. brevirostris in the black garb of immaturity. The Australian P. stictocephalus, with which Dr. Finsch is inclined to unite it, has a very close resemblance to the young of our bird, being not much larger, and only distinguishable by its blackish-brown bill, a brighter lustre in its dark plumage, and the presence on each side of the head of numerous narrow linear specks of white.

Large numbers are sometimes congregated in their roosting-place; and when disturbed or alarmed they rise into the air simultaneously and course about in a confused manner, resembling at a distance a flight of Rooks.

On one occasion I visited their roosting-place in the evening in order to watch their behaviour on assembling. On the banks of the Rangitikei river I found a number of them crowding together on the branches of a small kahikatea tree overhanging the water, and about twenty more performing gyrations high in the air, apparently surveying the ground before descending to roost for the night. Those already on the branches were very shy, and on our approach slipped away on the wing noiselessly and with the swiftness of an arrow. They do not breed in these roosting-places, but retire further up the streams, where they are less likely to be molested.

One of my brothers visited a breeding-place in the centre of a large “negro-head” swamp in the South Island, but the odour was so intolerable that he could not be induced to go there again. He found some hundreds of these Shags breeding together in a colony, the nests being placed close together on the clumps of “negro-head” standing out of the water.

Like the Black Sea-Shag, they retire to the “negro-head” swamps and to the lakes of the interior for the purpose of breeding, establishing themselves in large colonies, and returning to the same shaggery year after year. The low scrub fringing the shores of a lake or lagoon is the site usually selected; and the nests are constructed of broken twigs, dry flags, and rushes loosely placed together to the thickness of several inches, with sometimes an upper layer of soft dry grass.

In the Lake district there are shaggeries of considerable magnitude which are much valued page 172 by the natives, each colony of nests having its own proprietor, who exercises all the rights of ownership, visiting the ground at the breeding-season for the purpose of collecting the young birds, which are potted in the usual manner and are considered a great dainty. Captain Mair accompanied one of the Shag parties to the Tauranga river, at Lake Taupo, and saw 400 young birds collected in the course of a single day. Both the White-throated and the small Black Shag, he states, breed together in these localities, although apparently never pairing.

I visited one of these colonies at Matapiro (in the Hawke’s Bay district) on Jan. 29, and found nests in every stage of breeding. We saw naked young birds just extruded from the egg, looking like little leathery sacs of a flesh-brown colour, their sensitive young bodies full of tremor even in the strong sunlight; in other nests were young birds a stage more advanced, the whole surface of the body, with the exception of the head, blackened like the skin of a negro; in some nests two such little “niggers” were lying side by side with two unhatched eggs; in others, again, the black skin was covered with a dense, short growth of sooty-black down, the whole of the head and cheeks being entirely bare and flesh-white, darkening on the nape and then passing into black, with a gradual development of down on the neck, the bill and feet being black. In the most advanced state, the young birds had a thick-set growth of short down right up to the crown of the head, where it presented a well-defined outer margin, the whole covering being sooty black, with a sprinkling of white down along the margins of the wings, upon which the quill-feathers were just appearing; the naked skin of the crown, sides of the face, cheeks, and chin perfectly smooth and of a clean flesh-white, excepting only a narrow line of dark brown passing from the base of the upper mandible through the eyes, and becoming still narrower behind; bill and feet perfectly black.

In association with the nests of this species were two belonging to the Black Shag, and presenting a far more substantial appearance. One of these was empty; the other contained two young birds, of large size and covered with thick black down, the bare skin on the sides of the face, cheeks, and chin being bright lemon-yellow. These birds craned up their lanky necks as we approached them with a snare at the end of a long rod, took the situation in at a glance, clambered over the sides of the nest, and tumbled hurriedly into the stream below, thus beginning a new epoch in their lives!

In the Canterbury Museum there are two nests of the White-throated Shag, differing entirely in their construction. One of them is very compact, rounded in form, with a diameter of more than a foot, and a thickness of five inches, presenting only a slight depression for the eggs, and composed of weeds, grasses, and dry flags, on a foundation of broken twigs. The other is formed entirely of broken twigs, with the leaves attached, closely interlaced together, with a deep cavity for the eggs, the whole being securely placed in the fork of a small tree; it is, in fact, a compact structure, of a round symmetrical form, and very firmly put together. Each of these nests contains three eggs, all of which have the surface much soiled.

The eggs of this species exhibit much variety in shape and size. I have now before me a large series of specimens from my son’s collection, varying from the typical ovoid to a narrow elliptical form. The former measures 2 inches in length by 1·15 in breadth, and is of a clear pale green, with only a thin yellowish film over a portion of its surface; the latter measures 1·7 inch in length by 1·2 in breadth, and is of a paler green, thickly incrusted in places with chalky matter and stained over a great part of its surface to a dark yellow colour. Between these extremes there are numerous individual variations. An example received from Mr. Walter Shrimpton is both small and elliptical in form, measuring 1·8 inch in length by 1·1 in breadth; it is greenish white, with a faint gloss, the coating of chalky matter on the surface being thin and even.

* So named in honour of Mrs. Howard Vincent, who was the first lady to explore it.