Bird Life on Island and Shore
IX. The Bittern
IX. The Bittern.
The swamps and marsh land of Petane have for years supported a few pair of Bittern. From the beach road between the township of that name and Napier, one or more may sometimes be seen by those who know how and where to look. More often, wading furtively along the mud channels, or standing with bills pointing straight to the sky, they pass undetected. In the latter position, by the huge majority of wayfarers, they are regarded as snags.
The second Bittern's nest discovered was built within twenty yards of a road over which a big traffic rolled. At a slightly greater distance stood several cottages, so that proximity to settlement does not seem to repel the Bittern; perhaps, indeed, as in the case of the Banded Rail, the household cat may assist in the preservation of the species. The site of this nest was dry, the nest itself well hidden on all sides, concealed even from above by a growth of tall stiff rushes. Its construction, too, like that of the first found nest, was careless, the material used being such as grew about the immediate vicinity—rushes, flood-borne twigs, and dried grass. The five eggs, uncovered by the retreating bird, were of a pale olivaceous blue, unusually smooth on the surface, and somewhat blunt-ended. Over both nest and eggs was a distinct sprinkling of scurf from the body of the incubating bird. It was evidently anxious to return, and after our retirement we could observe from afar its cautious reconnoitring and approach. The eggs were much incubated, but even under these conditions it was over an page 92 hour and a quarter before they were again covered by the suspicious bird. Observation of this nest too was relinquished, proximity to the road making it unlikely that we should succeed in obtaining the necessary seven or ten days' quietude.
Our beats in searching these swamps, rush brakes, or samphire flats, were three-quarters of a mile or so in length. Throughout this covert the birds would run like pheasants before us, only rising when forced into the open. Though primarily a frequenter of marsh and swamp and unapt to rest elsewhere, yet on occasion these birds will alight on the sides of open-grassed hill elopes.
I am inclined to ascribe the remarkable snag-like elusive attitude so often to be noted in the Bittern as assumed in the first place, not for purposes of concealment, but in order to offer a minimum of resistance to the storms of his hunting-grounds—storms alike unavoidable and recurrent. page 94 Only in the second place perhaps has the attitude been utilised to mislead and beguile. This belief is based on an incident once witnessed by me at Tutira, where half a dozen hens and a rooster had been caught in the open by a sudden sharp sunlit downpour of warm rain. In their tepid tropical shower-bath, before my astonished gaze they stretched themselves into what seemed twice their natural length, the rooster specially transmogrifying himself into one long line from beak to tail, a line exactly adjusted to the slant of the almost vertical downpour. Other species, then, when so minded, can assume the Bittern pose. In that bird only has it become habitual when immobility is desired. Devised originally to deflect the rains of the open marsh, of the unsheltered fen, the posture has at length become used on any occasion requiring statue-like stillness.
About estuaries, swamps, and marsh lands the booming of the Bittern may be listened for in early October. Breaking through the roaring frog chorus may be heard the occasional “sphittock” of the Shoveller Duck, the long cheep of the Banded Rail, the rapid purr of its smaller relative the Swamp Rail, the petulant cry of the wakeful Pukeko, the wing vibration of flighting Grey Duck, but most remarkable of all the deep sibilant drum of the Bittern, its fainter inhalation, and then again the resonant musical boom.
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