Bird Life on Island and Shore
I. Porangahau—The Caspian Tern
I. Porangahau—The Caspian Tern.
Although the winter movements of littoral and lacustrine species are largely dependent on weather conditions, yet probably during the whole dead season there may in varying numbers be found on the Porangahau dunes, lagoons, beaches, and river-bed, Caspian Tern, Pied Stilt, Wrybill, Godwit, Pied Oyster Catcher, Redbill, Kittywake, Black Shag, Grey Duck, Black - backed Gull, Banded Dottrel, Sea Swallow, and perhaps Little Tern. Three times during 1910 these beaches were visited by J. C. M'Lean and myself, or by myself alone. In October we found 1 pair of Caspian Tern, 5 or 6 pair of Pied Stilt, 12 or 14 pair of Wrybill in several small parties, 3 pair of Godwit, 7 or 8 pair of Pied Oyster Catcher, a page 2 couple of pair of Redbill, a few Kittywakes, and a few Black-backed Gulls. On snags embedded in mud, Black Shag were conspicuous; about the open sands rested armies of Grey Duck, well out of reach of marauders.
At that date the pair of Caspian Tern were the only two birds out of the lot definitely purposing to build. Probably they had just settled down; probably, too, the additional pairs noticed later were due to arrive within a few days. The Black-backed Gulls were doubtless residenters; the remaining species were in all likelihood made up of wandering parties, one of them, the Godwit, rarely, if indeed ever, breeding in New Zealand; another, the Wrybill—not believed to nest in the North Island. Watching the last-named feeding in the gleaming sands freshly uncovered by the retreating tide, it was interesting to speculate as to whether the sweeping scythe-like action in feeding, a skimming of the surface of the wet sand, had helped to modify the remarkable crooked bill of the species, or had been adopted in consequence of it.
A month later in the year during a second visit to these delightful beaches we found Wrybill and Godwit gone, Caspian Tern sitting, and Redbills courting.1page break page break page 3
The Black-backed Gulls had selected their breeding sites. The Kittywake colony, though not intending immediately to lay, were yet annoyed at approach to their future nesting quarters, and in clouds swooped upon us with angry cries.
Ability “to look before and after” has been claimed as the special prerogative of man, proud man; but I can find no sharp line of demarcation. Doubtless he can recollect further back and foresee more clearly, that is all. We and our fellow-mortals, the beasts of the field, are digged alike from the same pit. There is no sudden break in nature. When it may seem so to our purblind eyes, we are no wiser than the child who marvels at the change from shell to chick. The Kittywakes of Porangahau foresaw the use to which that particular bit of beach was shortly to be put, as clearly as the architect when selecting the site of his future edifice.
Before proceeding further with remarks on the Terns, Gulls, and Kittywake haunting these dunes and shores, a few sentences may be devoted to the topography of the locality. The Porangahau River flows throughout its last reaches betwixt steep banks cut out of soft marl rock. Attempting page 4 to reach the sea, it is often forced, like many another New Zealand river, for some considerable distance to flow parallel to a banked beach, through whose loose shingle it percolates and filters. Not infrequently during heavy storms from the east, with even this escape blocked by high seas, the river waters are dammed back, and stored in a sort of reservoir or lagoon created by sand bar in front and dry land behind, such lagoon, however, always in the end breaking out, and the river again opening a fairly straight temporary gap. Normally the lagoon is daily filled and emptied by tides that pass up and down the tortuous, indefinite, ever-shifting, shallow course of the stream. On either side of the river mouth extend for miles narrow coast lines of sand and shingle.
Thus although on the southern shore natural conditions favour the birds, yet the northern is chosen. Sea-birds breeding about this river estuary have been driven by settlement from the naturally safer to the naturally less secure locality; it is but an example of one of the many factors that throughout modern New Zealand lessen, season by season, the numbers of shore birds. The Caspian Tern, Sea Swallow, and Kittywake of this beach thus have the restricted choice of building beneath the crest of the beach, thereby risking the overwhelming of their colonies by specially heavy seas, or of planting their nests on the lagoon's edge, thereby hazarding its rise by the inrush of the ocean. Some of the birds elect the one danger, some the other. One great Ternery extends beneath the crest of the beach, another along the edge of the lagoon. The opinions of the three pair of Caspian Tern also appeared to differ as to which spot was the less perilous, one pair page 6 nesting near the lagoon, the other two pair beneath the crest of the beach. The Kittywake plumped for the lagoon edge, and, as we shall see, suffered the fate of those who carry their eggs in the one basket.
The nest of the Caspian Tern is a rough-and-ready structure, built sparingly of such sea wrack and flood débris as may lie handy. The eggs, three in a clutch, are laid in November, their ground colour stone-grey, with deep umber markings set chiefly on the thicker end; over the whole surface there are markings also of a fainter hue of brown.
During our third or fourth day on the beach an egg hatched in the nest opposite the screen. This youngster enjoyed the terrific never-ceasing blast no more than we did ourselves. Whenever by the exigencies of plate removal or shifting of camera the hen was temporarily put off her nest, the chick would utter a sorrowful little wailing bark. Instantly on the return of her parent, like a rabbit skurrying to burrow, it would scramble again beneath its mother's breast for warmth page 8 and comfort. During the feeding of this chick by the male, it was the hen's custom to retire a yard or so distant, as if taking pleasure in seeing her offspring fed. There was an indescribable air of sober benevolence in the act very pleasant to contemplate. The chick becoming clamorous and no food forthcoming, I have seen the hen, as if to deprecate its annoyance, put the extreme tip of her bill into its little gaping throat.
Many breeds learn to tolerate the stranger within their gates; the Caspian Tern is not amongst the number. I may say at once that we were never in doubt as to the big Tern's feelings towards us. Frankly, they were those of implacable spleen. Throughout our acquaintance there was no movement that did not call forth shrieks and screams; almost every picture taken reveals the species scolding open-mouthed. The sight of us was an abiding exasperation to the fierce birds, our connection one long enduring duel. Certainly they failed to drive us off the beach by their remonstrances, but then, on the other hand, they did not themselves budge a foot; more than once they distinctly worsted us.
As pointed out, indeed, nearly every photograph portrays the Caspian Tern in belligerent mood, yet not a nest was deserted. It is satisfactory to be able to state that all the eggs known to us hatched safely. On the Porangahau beach that season there were added to the sum total of New Zealand shore birds six young Caspian Terns.
1 No more striking example perhaps could be cited of the dangerous adaptability of the feeding habits of birds than that of the Redbill—Hæmatopus unicolor. Our three tame specimens of this breed, free, of course, and with the run of Tutira Lake, its shores and marshes, would habitually share with tame Pukeko fragments of hard biscuit and wheat as fed to poultry.