A History of the Birds of New Zealand.
Sterna frontalis, Gray, Voy. Ereb. and Terr., Birds, p. 19 (1844).
Sterna albifrons, Peale, U. S. Expl. Exped., Birds, p. 279 (1848).
Sterna atripes, Ellman, Zool. 1861, p. 7473.
Sterna longipennis, Finsch, J. f. O. 1867, p. 339.
Native name.—Tara; “Sea-Swallow” of the colonists.
Ad. ptil. æstiv. suprà albicanti-cinereus, remigibus cano lavatis, primarii primi pogonio externo nigro, pennis minoribus ad apicem latè albis, reliquis intùs versùs apicem albis: caudâ albâ: capite et nuchâ nigris, fronte et facie laterali albis: subtùs albus: rostro nigro, ad basin brunnescente: pedibus rufescenti-brunneis: iride nigrâ.
Ad. ptil. heim. similis ptilosi æstivæ, sed fronte albâ latiore et vertice plus minusve albo vario.
Juv. capite cinerascenti-nigro, albido vario: suprà dilutè cinereus, obscurè-nigricante fasciatus et notatus: tectricibus alarum minimis nigricantibus.
Adult in summer. Crown of the head and nape black; a band immediately over the bill, the lores, and cheeks pure white; back and upper surface of wings pale ashy grey; the rest of the plumage pure white; the breast and sides of the body often suffused with a delicate rosy tint, which fades after death. Irides and bill black; legs and feet reddish brown. Length 16 inches; extent of wings 33; wing, from flexure, 11; tail 7 (the middle feather 3 inches shorter); bill, along the ridge 1·6, along the edge of lower mandible 2·25; bare tibia ·4; tarsus ·6; middle toe and claw 1·1.
Adult in winter. Differs in having the white frontal band more extended, and the black crown mope or less varied or spotted with white.
Young. Forehead, crown of the head, and nape greyish black, obscurely spotted or mottled with white; the whole of the back, the feathers composing the mantle, and some of the larger wing-coverts dark silvery grey, varied with white, and handsomely mottled and barred with dusky or greyish black; the smaller wing-coverts uniform greyish black, except along the edge of the wing, where they become white; underparts silky white, as in the adult. The barred character is most conspicuous on the scapulars and long inner secondaries; and both these and the tail-feather have crescent-shaped markings near the tips.
Nestling. Covered with buffy-white down, tinged with fulvous on the head and neck, and mottled with grey on the back.
Fledgling. Feathers of the back and the scapulars greyish white, with broad crescentic marks of black; wing-coverts prettily variegated with black; the down on the back buffy white, mottled and marbled with dark grey; wing-feathers (half an inch in length) silvery grey, broadly margined with white.
Obs. I have noticed in a bird so young that it was unable to fly the same roseate tint mentioned in the description of the adult.
Some years ago, when exploring among the shoals and sand-banks of the great Kaipara heads or basin, I observed thousands of these birds; and in this wild and unfrequented part of the coast they were so fearless that they coursed about our boat within a few feet of our heads, and the discharge of a gun among them only tended to increase their apparent interest in us.
This species of Tern breeds in large colonies, as many as 200 or more being sometimes associated together. My son Percy observed in December a vast crowd of them on a small rocky island near the Taranaki Sugar Loaves. This is a favourite breeding-ground, and the birds were so closely packed that from the deck of the steamer they presented the appearance of a fall of snow. On one occasion the crew of the ‘Hinemoa’ landed at this place, and collected several bucketsful of the eggs.
On the small island of Motiti I found a large community of them occupying one end of it, and the Red-billed Gull the other, the two nesting-places being as far apart as possible. On the high intervening ground Larus dominicanus had established a breeding-place, as already mentioned.
On its nesting-ground being invaded this Tern shows fight in a very determined manner, coming in a bee-line for the intruder’s face, till within about a couple of feet, and then darting off at a sharp angle with a snapping cry of remonstrance. Captain Fairchild has known them even bolder, and has had his hat knocked off by the rapid action of their wings. By the end of February the young birds have joined the general community on the sand-banks, but they may be easily distinguished by the dark plumage of their upper surface and by their more sibilant cry. The eggs are deposited on the bare rock, often within reach of the sea-spray; and, as a rule, there are two eggs to each nest. They are usually of an elegant ovoido-conical form, measuring 1·9 inch in length by 1·3 in breadth; and they present great beauty and diversity in their colouring. The ground-tint varies from a clear greyish white to a delicate greyish green, and from a pale yellowish brown to a dark cream-colour. They are marked and spotted with purplish and dark brown in every variety of character: some have the entire surface studded with clear rounded spots, occasionally confluent; others have the marks broad and irregular; while in some examples they are spread into large dark biotches, covering a great portion of the surface. Some specimens are freckled all over with light brown, and splashed at intervals with darker brown; others have a smudged appearance, as though an attempt had been made to obliterate the markings. In the Canterbury Museum there is a curious example, having the entire surface covered with marbled veins of dark brown; and another (collected by Mr. Fuller on the Waimakariri beach) is of a delicate pinkish-brown tint, with a broad zone of confluent spots towards the larger end, and numerous scattered specks of a rich reddish-brown colour.
Sterna antarctica, Wagler, Isis, 1832, p. 1223.
Hydrochelidon albostriata, Gray, Voy. Ereb. and Terr., Birds, p. 19, pl. 21 (1844).
Sternula antarctica, Bonap. C. R. xlii. p. 773 (1856).
Hydrochelidon albistriata, Bonap. C. R. xlii. p. 773 (1856).
Sterna cinerea, Ellman, Zool. 1861, p. 7473.
Hydrochelidon hybrida, Finsch, J. f. O. 1867, p. 347.
Ad. æstiv. suprà saturatè cinereus, uropygio conspicuè albo: capite summo nuchâque nigris: lineâ faciali a rostri basi directè per regionem paroticam ductâ, albâ: genis et corpore subtùs toto pulchrè cinereis, subcaudalibus albis: remigibus extùs cinerascentibus, intùs albis, scapia albis, primario primo extüs nigricante: caudâ dilutè cinereâ, rectricibus versùs basin albis, rectrice extimâ ferè omninô albâ, versùs apicem cinerascente: rostro lætè flavo: pedibus lætè flavis, unguibus saturatè brunneis: iride nigrâ.
Ad. hiem. similis ptilosi æstivæ, sed fronte et pileo cinerascenti-albis, nigro variis.
Juv. pileo summo et laterali saturatè cinerascentibus: lineâ a basi rostri per oculum ductâ et ad torquem nuchalem angustam conjunctâ, nigricante, albo variâ: tectricibus alarum, scapularibus et secundariis intimis brunneo subterminaliter notatis: rostro nigro, versùs apicem brunnescente: pedibus sordidè flavis.
Adult in summer. Top and sides of the head and nape velvety black; from the gape a broad streak of white passes under the eyes, and is continued to the nape, forming a border to the black plumage; upper and lower tail-coverts pure white; the rest of the body beautiful pearl-grey, darker on the upper surface; wing-feathers darker grey, with white shafts, the first primary margined on the outer web with dusky black; tail-feathers dark pearl-grey, the outermost ones inclining to white, and all of them white on their under surface. Irides black; bill bright yellow, sometimes shaded with brown towards the base of the upper mandible; legs and feet bright yellow, the claws dark brown. Total length 12 inches; wing, from flexure, 10·25; tail 4·5 (middle feather 1·75 inch shorter); bill, along the ridge 1·1, along the edge of lower mandible 1·5; tarsus ·6; middle toe and claw 1; hind toe and claw ·2.
Adult in winter. Differs only in having the forehead and crown greyish white, mottled with black.
Young. Top and sides of the head dark ash-grey; the lores, a mark beyond the eyes (sometimes the vertex), and a narrow nuchal collar obscurely mottled with black; throat whitish; upper wing-coverts, scapulars, and long inner secondaries with a subterminal mark of brown, and with paler tips; the rest of the plumage as in the adult. Bill black, inclining to light brown towards the base; legs and feet dull yellow.
Younger state. Crown and nape greyish brown mottled with black; a small spot of black in front of the eyes, and a larger one behind covering the ears and spreading outwards; plumage of the upper parts much darker than in the adult; upper wing-coverts, scapulars, and inner secondaries blackish brown, darker towards the end and terminally margined with dull ochreous yellow; tail-feathers blackish brown in their apical portion and narrowly tipped with white; underparts clouded with grey; throat, part of fore neck, and under tail-coverts pure white. Bill brown, changing to yellow towards the base of lower mandible.page 71
This handsome Tern is very common in every part of the South Island, but is not so plentiful to the north side of Cook’s Strait.
In the Canterbury Province it is particularly abundant, frequenting all the river-courses, and often spreading far over the plains. Within a few miles of the city of Christchurch I have observed it, in large flights, following the farmer’s plough and picking up grubs and worms from the newly turned earth. I once saw a Hawk swoop down amongst a flock occupied in this manner and single out a bird for pursuit, but the active Tern easily evaded its enemy and then returned to its occupation behind the plough. It also frequents the cornfields and pastures, and, by devouring caterpillars and other insect pests, proves itself a valuable friend to the agriculturist.
It is remarkably active on the wing, performing very rapid evolutions, and often chasing its fellows in a playful manner and with much vociferation. When resting on the ground, the members of a flock stand closely packed together, and may be seen constantly stretching their wings upwards in the peculiar manner already noticed in treating of Sterna frontalis.
There is a spot of great beauty on the Waikato river where the Karapiro creek empties its placid waters into the turbulent stream of the “tua-whenua.” The place I refer to is just below the bridge on the outskirts of the township of Cambridge—the furthest point on the river navigable for steamers. Immediately below this bridge there is a rocky obstruction in the bed of the river which causes an eddy of considerable force and velocity. The basin below is comparatively smooth, the river widening again at this point; and the banks, clothed with rank verdure, rise abruptly on both sides of the Waikato. Beyond are the well-kept homesteads of the settlers and far away in the background the rugged outlines of Maungakawa and Pukekura. In this picturesque spot, for the best part of a fine Sunday afternoon in spring, my thoughts absorbed “with the fairy tales of science and the long result of time,” I watched a pair of these birds disporting in the air. For hours together they coursed up and down this little reach in the river, never once dipping to the stream—indeed the water was too rapid at this point to allow of surface fish being found there: high above the water, now with a winnowing Pigeon-flight, now hovering a moment in the air—rising and falling with the play of their changeful fancy—coursing first up stream to near the bridge, then wheeling round; sometimes skimming low at the place where the rapids were boiling over their rocky bed, as if to take a closer observation, and then, on reaching the bend in the river, sharply wheeling back again; and so on and on, now higher now lower, regulating their more rapid actions by a dexterous movement of their swallow-tails, and at every turn showing the snowy whiteness of their tail-coverts and their lovely coral bills. So these pretty fairy beings for hours together, without a rest and apparently for sheer enjoyment, continued to beat the air with their pointed pinions, seldom uttering a sound except when in close proximity to each other, and then ke-e was the simple watchword.
From watching these aerial performers in their fantastic flight till the sun had declined and its shadows had vanished, I ascended the high bank overlooking the river and witnessed one of those gorgeous sunsets on the Pirongia range for which this part of the North Island is so justly celebrated. No artist’s brush can depict the glory nor human tongue describe the splendour of this sunset display. Presenting to the eye mountains of burnished gold in a sea of matchless colours and brilliant effects, the illusion lasts but a little while and then melts away in ever-varying coruscations of golden light till the sky is bathed in a soft grey twilight, to be quickly succeeded by the shades of night. Even Mr. Procter, the famous astronomer, declares that although in the sunset displays of America and Australia he has seen colours more striking, yet “for combined beauty and grandeur” the sunset which he once witnessed in New Zealand surpassed anything he had ever seen.
From Hamilton Bridge, lower down the river, on a subsequent occasion, I watched a pair of these Terns engaged in the more serious business of fishing. Here, again, nothing could be more pretty than the arrowy flight of this bird up and down the stream. Skimming near the surface and page 72 almost touching the water, it would ever and anon poise itself in the air for a few seconds, as if to take steady aim, and then drop upon its finny prey—a small kind of Galaxias. Immediately on capturing this it would sweep upwards so as to have some play in the air as the little fish fell from its beak and had to be caught again in the right position for swallowing. Up and down the open reach these birds kept up this untiring flight for hours together, their lively grey and white plumage shown off to the best advantage against the dark banks and deep waters of the Waikato.
On one occasion, however, when travelling in the Lower Waikato, I observed a very considerable flock in a meadow quite close to the railway-line, where several ploughs were at work. I have also met with smaller flocks at Onehunga, Maketu, Hastings North, and at the mouths of the Rangitikei and Wanganui rivers.
Mr. Kirk writes that the local name of this bird, in the neighbourhood of Cape Kidnappers, is the “Plough-bird” or “Plough-boy,” given on account of the persistent manner in which it follows the farmer’s plough for the purpose of picking up the grubs and worms that are exposed in this operation.
On the habits of this species far inland, Captain Mair has sent me the following interesting note:—“During the calm summer evenings in December, 1879, I observed hundreds of these little birds flying round the clumps of black birch trees which here and there dot the course of the Takiahuru stream, running through the Murimotu-karioi plain on the S.E. base of Ruapehu mountain. My curiosity being aroused, I climbed to the top of one of these trees, just after sunset, and obtained a close view of these birds hovering round the trees, and ever and anon darting hither and thither, very much in the zigzag manner in which bats pursue their prey. I found that the birds were chasing small moths, beetles, &c., and now and then when a large green beetle came booming along in its flight from the plain seeking a resting-place in the trees, a score of these pretty little birds would dart after it, uttering soft plaintive cries, till one more lucky than the rest carried off the prize. Both in that month and in the preceding one I found numbers of the young of this species lying, or squatting, on the sand-banks far up the course of the Whangaehu river.”
Like the other Terns * this species breeds in colonies, placing its eggs (usually two in number) on the bare ground, without any attempt at forming a nest. It defends its breeding-place with a considerable amount of spirit, darting towards the intruder’s head, and uttering at the same time its harsh cry. The eggs are of an elegant ovoido-conical form, measuring 1·6 inch in length by 1·2 in breadth; and they present a considerable amount of diversity in their colouring and markings, varying from a pale yellowish brown to a dull olive, and marked over the entire surface with blackish brown, the spots being generally more numerous at the thicker end, but sometimes confluent in the middle, forming an irregular blotched zone. A specimen in the Canterbury Museum has the ground-colour of a pale greenish white, minutely speckled all over, but particularly at the thick end, with purplish brown; another (collected on the 22nd of October) has the entire surface covered with small round spots. One of the specimens in my son’s collection is somewhat ellipto-conical in form, measuring 1·9 inch in length by 1·25 in breadth, and is of a pale cream-colour, thickly and irregularly spotted with blackish brown, in different shades, over the entire surface.
Sterna tschegrava, Lepechin, N. Comm. Petrop. xiv. p. 500 (1769).
Sterna caspia, Pallas, N. Comm. Petrop. xiv. p. 582 (1769).
Sterna megarhynchos, Meyer and Wolf, Taschenb. deutsch. Vögelk. ii. p. 457 (1810).
Thalasseus caspius, Boie, Isis, 1822, p. 563.
Hydroprogne caspia, Kaup, Natürl. Syst. p. 91 (1829).
Sylochelidon balthica, Brehm, Vög. Deutschl. p. 769 (1831).
Sterna schillingii, Brehm, tom. cit. p. 770 (1831).
Sylochelidon caspia, Brehm, tom. cit. p. 770 (1831).
Helopus caspius, Wagler, Isis, 1832, p. 1224.
Thalassites melanotis, Swains. B. of W. Afr. ii. p. 253 (1837).
Sylochelidon strenuus, Gould, P. Z. S. 1846, p. 21.
Sylochelidon melanotis, Bonap. C. R. xlii. p. 772 (1856).
Sterna melanotis, Hartl. Orn. Westafr. p. 254 (1857).
Sterna vulgaris, Ellman, Zool. 1861, p. 7472.
Thalasseus imperator, Coues, Pr. Phil. Acad. 1862, p. 538.
Ad. ptil. æstiv. suprà dilutè cinereus, uropygio et supracaudalibus albis: caudâ albâ: tectricibus alarum dorso concoloribus: remigibus extùs canescentibus, primariis versùs apicem saturatioribus, scapis albis, pennis minoribus et secundariis dorsalibus pallidè cinereis: pileo et nuchâ cristatä nigris: facie laterali a narium basi ductâ cum collo laterali et corpore subtùs toto albis: rostro lætè corallino, flavo vario, versùs apicem brunnescente, spice ipsâ corned: pedibus nigricanti-brunneis: iride nigrâ.
Ad. ptil. hiem. similis ptilosi æstivæ, sed pileo albo minutè nigro striolato.
Adult in summer. Forehead and upper part of the head, described by a line from the posterior edge of the nasal groove, on each side, passing immediately under the eyes, and meeting in an acuminate point below the occiput, satiny black; back, rump, and upper surface of wings and tail delicate silvery grey; primaries darker grey, with white shafts; the rest of the plumage pearly white. Irides black; bill beautiful coral-red, mixed with yellow, and shaded with brown near the tips of both mandibles, which are horn-coloured; legs and feet blackish brown. Length 22 inches; extent of wings 53; wing, from flexure, 16·25; tail 6·25 (middle feather 1·5 shorter); bill, along the ridge 2·6, along the edge of lower mandible 3·6; bare tibia ·5; tarsus 1·75; middle toe and claw 1·5.
Adult in winter. Differs in having the black plumage of the head largely spotted with white, especially on the forehead and lores.
Obs, At the breeding-season this bird has the plumage suffused with an extremely delicate roseate hue, which fades away after life is extinct, but does not wholly disappear from the preserved skin.
Young. Has the vertex and crown similar to the adult in winter, but the white preponderating, and the coronal cap extending halfway down the cheeks; the primaries are sooty grey, and the wing-coverts greyish brown with paler edges. Bill reddish brown.page 74
Note. Dr. Elliott Coues, in his “Review of the Terns of North America” (Proc. Phil. Acad. l. c.), makes the following remarks on the synonymy of this species:—“The proper specific appellation of the Caspian Tern is not ‘caspia, Pallas,’ but ‘tschegrava, Lepechin,’ which latter name is proposed in the same work in which Pallas calls the bird ‘caspia,’ but has priority by several pages. As, however, the word is not only barbarous, but exceedingly cacophonous, and especially as caspia has become so well established by common consent, I do not think it would be expedient to supersede Pallas’s name in view of the very slight priority of that of Lepechin.”
The history of this fine Tern has already been so fully written that I deem it almost sufficient to record here that it occurs all round the New-Zealand coasts, where its habits are the same as in other parts of the globe. It inhabits the Palæarctic and the greater part of the Nearctic Regions, also the African, Indian, and Australian coasts. It is a rare summer visitant to the eastern and southern shores of England.
It is usually met with in pairs; but I have occasionally observed parties of five or more resting on the sands near the mouths of our tidal rivers. It subsists entirely on small fish, for which it plunges into the water with considerable force; and at certain seasons it is accustomed to follow the shoals of sprats far up the river-courses, where it may be seen hovering lightly over the water in pursuit of its finny prey, and occasionally alighting to rest on a jutting stump or projecting point of rock. I have seen one capture a small flounder, and kill it by battering before swallowing it. It often makes several feints at the water before dropping into it; but the bird never misses its aim, and on rising again with a fish usually takes a wide sweep on the wing whilst stowing it away in its capacious crop. I have observed that, on the wing, this species does not move its head to and fro in the manner of the smaller Terns, but carries it vertically, with its powerful beak pointing downwards. “When resting on the ground the apparently disproportionate head gives the bird an ungainly appearance; but this disappears the moment the wings are expanded; and the flight, which is generally performed in wide circles, may be described as very easy and graceful. It is less active, however, on the wing than the smaller Terns. Nevertheless it appears to have the most perfect self-control; for example, I observed one pursuing a direct flight up a river-course, at a high elevation, when it met another coming in the opposite direction at a lower level. Moved by some sudden impulse it abruptly and quickly wheeled right-about, dropped to the lower plane, and succeeded in overtaking the other bird. Writing of it, the Earl of Pembroke says: “The Tern, if the sea be smooth, has a neat little way of picking up small morsels from the surface, and, if necessary, makes a very respectable Gannet-like splash; never, however, as far as I have seen, immersing himself, and always keeping his wings in motion to get him up again.” Its ordinary cry is harsh and unmusical, consisting of a loud rasping note, not unlike the low cry of the domestic Goose; at other times it utters a long peevish squeal or whistling cry, fairly represented by the syllables queeâ-queeâ. When resting on the sands it is habitually silent, but always utters its guttural cry when preparing to take wing.
The breeding-season of this species extends from November to January. The young birds, however, follow their parents up to the end of March, settling down with them on the sands, quivering their wings as if impatient of attention, and making an incessant squealing or whining cry. The eggs, usually two in number, are deposited on the bare sand, a slight hollow in the surface meeting the requirements of a nesting-place. They are ovoido-conical in form, measuring 2·7 inches in length by 1·9 in breadth, and varying from creamy white to a delicate greenish-white tint, the whole surface marked with spots and blotches of dark brown, intermixed with pale splashes of purple, these markings being most numerous at the thicker end. It should be mentioned, however, that, as in the case of other Terns, the eggs present some variety both as to size and colour; there is a specimen in the Canterbury Museum (of a pale yellowish-brown tint, thickly marked and spotted with dark brown) which measures only 2·4 inches by 1·6.
(Little White Tern.)
Sternula nereis, Gould, P. Z. S. 1842, p. 140.
Sterna parva, Ellman, Zool. 1861, p. 7473.
Sterna nereis, Pelz. Verh. zool.-bot. Gesellsch. Wien, xvii, p. 818 (1867).
Sterna minuta, Finsch, J. f. O. 1867, pp. 337, 347.
Ad. ptil. æstiv. suprà dilutè cinereus, tectricibus alarum dorso concoloribus: remigibus intùs albis, extùs cano lavatis, primariis duobus externis extùs nigricantibus, scapis albis, pennis minoribus versùs apicem albis, secundariis intimis dorso concoloribus, dorso postico et uropygio cum supracaudalibus albis: caudâ albâ: pileo postico et nuchâ cum regione oculari et supraparoticâ nigris: fronte latâ, genis et facie laterali et corpore subtùs toto albis: rostro lætè flavido: pedibus flavis, unguibus nigricantibus: iride nigrâ.
Ad. ptil. hiem. similis ptilosi æstivæ, sed pileo summo albo nigro vario: nuchâ nigrâ.
Juv. fronte et pileo cinerascenti-albis fuscescente variis: lineâ crescente ab oculo postico circà nucham productà nigrâ: suprà dilutè cinereus, plumis versùs apicem fasciâ irregulari brunneâ transnotatis: rostro flavicantibrunneo: pedibus sordidè flavis.
Adult in summer. Forehead and along the base of upper mandible white; spot in front of each eye, crown of the head, and nape black; throat, fore neck, and all the under surface silvery white; hind neck, shoulders, back, and upper surface of wings delicate silvery grey, darker on the primaries; rump and tail, with the upper and lower coverts, pure white. Irides black; bill bright yellow; tarsi and toes yellow, the claws darker. Length 9 inches; wing, from flexure, 7·5; tail 3 (median feathers 1 inch shorter); bill, along the ridge 1·25, along the edge of lower mandible 1·35; tarsus ·6; middle toe and claw ·7.
Adult in winter. Differs in having the crown of the head white, mixed with black, darkening outwards, the nuchal collar being entirely black.
Obs. In some examples the first primary is margined on the outer web with black; in others it is of a uniform dark grey.
Young, Forehead and crown greyish white, mottled with dusky; from the eyes a crescent of greyish black, which encircles the occiput; the plumage of the upper parts silvery grey, mixed with white, and many of the feathers with an irregular wavy mark of dark brown near the tip; the smaller wing-coverts greyish brown; underparts white, as in the adult. Bill yellowish brown; feet dull yellow. The tail is less acuminate at the sides than in the fully adult bird.
This is the smallest of our Terns, and is the southern representative of the Sterna minuta of Europe. It is tolerably common on all our coasts, and occurs also very plentifully along the shores of Western Australia.
It is very active in its movements, flies high, turns in the air with facility, and dips into the water after its prey in a very adroit manner. When resting on the sands it appears, owing to the page 76 shortness of its tarsi, to be actually lying on its breast; but it seldom remains long in this position, being far more restless than the other species. Rising silently, it mounts in the air, and having marked out a fishing-ground, hovers first to one end of it and then to the other, repeating the circuit with the most regular precision. It is less sociable than the other Terns, never assembling in flocks, but always associating in pairs, usually hunting together in silence but with an occasional call-note, sounding like crek-crek. Sometimes four are seen in company, but this only represents a family party, the additional members being the young birds of the year.
During the breeding-season it is very clamorous, especially when its nesting-ground is invaded or even approached. It deposits its eggs on the bare shingle, without any attempt at forming a nest, merely selecting a natural depression suited to its own size; and the colour of the eggs harmonizes in a remarkable manner with their surroundings.
There is nothing more interesting in the study of oology than the systematic way in which the colouring of eggs (and particularly those of sea-birds) is adapted to their natural environment.
Captain Mair has furnished me with a remarkable instance of this law of assimilative colouring for protective purposes. In December, 1875, he visited the Rurima Rocks, in the Bay of Plenty, and found large numbers of Larus scopulinus breeding there. In some localities the nests—roughly formed and lined with feathers—were placed in the thick masses of wild spinach or in the midst of “sand-fire.” In all such cases he observed that the eggs which these nests contained were splashed over their entire surface with large green blotches, thus assimilating their colour to the surrounding vegetation; whilst other eggs (belonging to the same species), deposited on the white sand in the immediate vicinity, had a totally different appearance, being of a light stone-colour, and so marked as to harmonize exactly with their sandy surroundings.
It is difficult, however, to account for the very intricate marking that distinguishes the eggs of Larus bulleri from those of its near allies, the breeding-habits of these birds not being, so far as I am aware, in any way dissimilar. An egg of the last-named species in my son’s collection is of a creamy stone-colour, with a broad irregular inky zone near the larger end, splashed on its edges with umber-brown, the rest of its surface marked, in a very eccentric way, with widely-spread hieroglyphics of the same dark colour. Possibly these markings are intended to simulate minute fragments of seaweed.
But assuming this protective resemblance to be a chief factor in determining the natural colours and markings on the surface, it is indeed very curious to observe how sometimes the eggs in one nest, produced at short intervals and all subject alike to the same conditions as to their future safety, differ from one another in their coloration. There can be no doubt that the colouring of birds’ eggs, which is chiefly due to animal matter deposited on the surface of the shell and capable of being rubbed or scratched off, must be to a large extent influenced by the state of the producer’s health and by any special sensations to which the bird may be subjected shortly before the extrusion, for it is well known that, even in the case of many birds that produce highly-coloured eggs, the hard shell is found to be perfectly white only the day before it is laid. Even Mr. Hewitson, who, in his ‘Eggs of British Birds’ (Intr. p. viii), declines to admit the general rule that the varied and beautiful hues which adorn the eggs of birds are given as a protection against discovery and destruction, is constrained to say:—“That there are several instances in which the eggs of birds are admirably adapted to and closely resemble in colour the ground upon which they are deposited, I have frequently found, much to my annoyance, when in search of them; and these are just the instances where such protection is most necessary, and where contrasting colours would lead to detection; such is the case amongst those birds which, making little or no nest, deposit their eggs, for the most part, upon the bare ground, or the shingle of the sea-beach, and leave them uncovered on the least alarm.”
This species usually lays two eggs; these are of a regular oval form, measuring 1·4 inch in length by 1·05 in breadth, and are of a yellowish white, the whole surface marked with obscure spots of purplish grey.
(White-Winged Black Tern.)
Sterna fissipes, Pallas, Zoogr. Rosso-Asiat. ii. p. 338 (1811).
Sterna leucoptera, Meisner u. Schinz, Vög. d. Schweiz, p. 264 (1815).
Hydrochelidon leucoptera, Boie, Isis, 1822, p. 563.
Viralva leucoptera, Steph. Gen. Zool. xiii. p. 170 (1825).
Hydrochelidon nigra, Gray, Gen. of B. iii. p. 660 (1846).
Ad. ptil. æstiv. suprà niger, niger, dorso et scapularibus paullò fumoso lavatis: dorso postico et uropygio albis: caudâ albâ: tectricibus alarum minimis albis, medianis et majoribus pulchrè cinereis: remigibus nigris, primariis interioribus canis, secundariis nigris dorso concoloribus: facie laterali et corpore subtùs toto nitidè nigris: crisso et subcaudalibus albis: subalaribus nigris, extùs albo notatis: rostro nigro: pedibus pallidè rubris: iride nigrâ.
Ad. ptil. hiem. suprâ dilutè cinereus, collo postico nigricante notato: tectricibus alarum dorso concoloribus, quibusdam minoribus versùs basin brunnescentibus: remigibus nigricantibus, scapis ochraceis, primariorum pogonii interni dimidio albo, secundariis cinereo lavatis: rectricibus suprà cinereis, externis albicantibus angustè albido limbatis: facie et collo lateralibus torquem interruptum collarem formantibus: subtùs omninò albus: rostro nigro, versùs basin rubescente: pedibus flavidis.
Adult in summer. Head, neck, and all the under surface shining black; the whole of the scapulars, and the back, smoky black; upper wing-coverts dark grey, becoming white towards the edge of the wing; first two primaries greyish black, with white shafts, and broadly marked with white on their inner webs; the rest of the primaries dark silvery grey, smoky on their inner webs; secondaries sooty grey, the inner ones darker; rump and tail, with upper and lower coverts, pure white. Irides and bill black; legs dull red. Total length 8·5 inches; extent of wings 21; wing, from flexure, 8; tail 2·75; bill, along the ridge ·9, along the edge of lower mandible 1·25; bare tibia ·25; tarsus ·75; middle toe and claw 1; hind toe and claw ·2.
Adult in winter. Forehead, sides of the head, and all the under surface pure white; occiput, ear-coverts, nape, and hind neck greyish black; upper surface of back, wings, and tail dark grey; the small wing-coverts shaded with brown; the primaries sooty black, with white shafts; the secondaries with dark shafts, and tinged more or less with grey.
I know of only one instance of the occurrence of this beautiful Tern in New Zealand. On the 12th of December, 1868, Mr. D. Monro shot a pair of them on the Waihopai river-bed in the provincial district of Nelson; and one of these is now in the Colonial Museum. They were in full summer plumage, and were associating with a large breeding-colony of Sterna frontalis; but whether they were actually nesting themselves, Mr. Monro was not able to ascertain. He mentions, however, that there was only a single pair of this species in the flock, and that they uttered at intervals a harsh croaking note.
This Tern has likewise been discovered in Australia since the publication of Mr. Gould’s ‘Handbook’; and, as it is unquestionably the same form as that inhabiting the Palæarctic Region, the species enjoys a wide geographical range.
(The Little Noddy.)
Anous cinereus, Gould, P. Z. S. 1845, p. 104; id. B. Australia, vii. pl. 76 (1848).
Procelsterna albivitta, Bp. Compt. Rend. xlii. 1856, p. 773.
Sterna cinerea, Schlegel, M. P.-Bas, Sternæ, p. 38 (1863).
Anous albivittatus, Finsch, P. Z. S. 1877, p. 776.
Pelecanopus pelecanoides, Gray, List B. Brit. Mus. pt. iii. p. 180 (1844).
Ad. suprà dilutè cinereus: pileo cum collo postico et corpore subtùs toto albis: tectricibus alarum dorso concoloribus pallide brunneo paullò lavatis: primariis schistaceo-cinereis: secundariis conspicuè albo terminatis: caudâ omninò schistaceo-cinereâ: rostro nigro: pedibus nigricanti-brunneis, palmis sordidè flavis.
Adult (N.-Z. example). Head, neck, and underparts generally pure white; upper surface delicate French-grey, fading away to nothing on the hind neck, and deepening to dark ash-grey on the quills and tail-feathers; the outer web of the first primary blackish brown; the inner webs of all the primaries whitish on their anterior margin; the shafts dark brown above, whitish at the base, and entirely white on the under surface; the secondaries with a conspicuous terminal margin of white. Bill black; legs and feet blackish brown, with yellowish webs. Length 11·5 inches; wing, from flexure, 8; tail 4·25; bill, along the ridge 1, along the edge of lower mandible 1·4; bare tibia ·25; tarsus ·85; middle toe and claw 1·25.
Obs. On a comparison of this species with the more northerly Anous cæruleus, Mr. Howard Saunders remarks (P. Z. S. 1878, p. 212):—“A. cæruleus is smaller than A. cinereus, Gould, and is darker all over, especially on the underparts, which are blue-grey, whereas in A. cinereus they are nearly white. The differences are too great to be explained away as being due to age, and I admit the distinctness of the two species; but they are very closely allied. The fact of their being found in such close proximity within so limited an area is very remarkable.”
The unique New-Zealand example of this bird was obtained at Cape Maria Vandieman in the early part of 1882. Mr. Robson, to whose kindness I am indebted for the skin, furnished me with the following account of it:—“After a heavy S.W. gale my sons were going through some large flax bushes and came upon this Tern in the middle of one of them. It was still living, but so much exhausted that it could only flutter a short distance, so that it was secured without difficulty. I may add that another was observed on the wing, one very calm day, there being very little doubt about the dientification.”
Dr. Crowfoot says of this species (Ibis, 1885, p. 265):—“These Grey Terns, called by the Norfolk-Islanders the ‘Little Blue Petrel,’ are fairly numerous during the breeding-season. They lay their eggs on Phillip and Nepean Islands and the neighbouring rocks. The eggs are usually placed on inaccessible ledges, but often on the sand, sometimes not many feet above the sea, but usually from 80 to 2000 feet. They make no attempt at a nest, and lay only one egg, which is the most easily broken of all the sea-birds’ eggs found on these islands. The eggs much resemble those of the other species of Noddy, but the ground-colour is rather darker, and the spots are numerous, small, and more generally distributed over the whole surface than in the eggs of the other species. They measure on an average 1·6 inch in length by 1·12 in breadth, and vary but little either in size or in markings.”
* Respecting Sterna frontalis Mr. Percy Seymour writes to me:—“On the 22nd November I examined about a thousand nests of this species on Tomahawk Island, Otago Peninsula. Eggs two and three in number. This cannot be accounted for, as. Mr. Potts suggests, by supposing that more than one bird laid in one nest. In one instance two very peculiar eggs were found in the same nest; they were of a pinkish colour, and spotted with red, very unlike the other eggs of this species. It is altogether outside the bounds of probability that the only two eggs of this description, out of more than two thousand eggs altogether, should by a coincidence have been laid by two different birds. A few of the nests contained only one egg each, but in these-cases the eggs were usually fresh, while in the other nests they were more or less incubated.”