MARINE NATURE NOTES

Otago Daily Times, Issue 22824, 7 March 1936, Page 2

MARINE NATURE NOTES

Written for the Otago Daily Times. By David H. Gbaham, F.R.M.S., F.Z S. SEA BIRD FOR IDENTIFICATION. MACKEREL GULL. A dried specimen of a red-billed sea gull has been sent to me by a Port Chalmers resident to whom I am indebted for the information that he and many others have always known this small gull as the Cape pigeon. He has asked me to describe the distinctive colourings of the two birds and to say whether the gull is useful or otherwise. Quite a number of people in Otago have fallen into the error of associating the red-billed gull with the Cape pigeon, which is a totally different bird both in its ijolourings and habitat. The red-billed gull ia known throughout New Zealand us the mackerel gull, with its red bill, white head, white breast, red legs and feet; it is not found far from land. The Cape pigeon, as a rule, is not found near land; it is longer than the gull, has a sooty brown head, a black bill and dark brown legs, back, white spotted with black, so my-correspondent will have no difficulty in distinguishing one bird from another, except that the young gull is mottled with brown on the back and wings. I have often stood and studied these mackerel gull, both at Dunedin and as far north as Spirits Bay. To me they are one of the most amusing birds to watch — fascinating and full of interesting study; their antics, their attitude to each other, their watchfulness of human beings or dogs are most artful. I have seen a terrier dog almost frantic in attempting to catch a gull which kept only just a safe enough distance to elude capture and yet keep the dog pursuing. It is interesting to observe with what jealousy they view, and with what boldness they attack, any of their kind who may be engaged in devouring the choicest morsels, and to hear the favoured ones with the curious chuckling noises they make in their anxiety to despatch these lest they should lose them to another bird. I have seen scores of these gulls flying swiftly up and down and around from all quarters, shrieking and literally calling for food. When my mate began to clean a fish and started to throw it overboard, the sea round the stern of the moving launch was almost covered with gulls, and I have seen them on the wing so abundant as to cast a shadow over the launch. It is amazing to stand steering and watch the gulls nimbly dodging and swooping down and catching the pieces of fish offal in the air. Sometimes when I was coming back from Cape Saunders, nearing the Otago Heads, not a gull would be seen, but once anything was thrown overboard only a few minutes would elapse before we were surrounded with shrieking birds, all in motion like pieces of white paper in a whirlwind. Their flight is swift and lively, and it makes an interesting study, this flying at all angles. Then at times I have seen them bo glutted with food as to reduce their power of speed, in which case they rest till the advancement of digestion restores their wonted powers; then they return to the feast with the same gusto as before. As often as not the successful gull is so -harassed by his own kind and larger gulls that the coveted morsel is dropped, and in a twinkling there is a mad rush of wings and a wild scramble with much squawking from all the other gulls endeavouring to secure the prize before it sinks below the surface. And so it goes on till all the offal is eaten; then they fly to some headland to clean and preen their feathers. It is at one of these places when the gulls have congregated that a great deal of amusement can be obtained. It may sound ridiculous to my readers, but with no stretch of imagination the author has often seen them indulging in what appears to me as " I m the King of the Castle." The highest part of a heap of rocks, or an anchored boat serves ae the " castle," and one may watch for long enough at these gulls having turns in pushing one another off the highest part. The one on the top will extend hie neck and utter loud, derisive calls, challenging the others to fight. In a second a bird with sufficient courage will fly straight to the "king' (challenger) and either secure the " castle or swoop past. Ae often as not the challenger flies to meet the foe, and while it is so doing the neaest gull takes possesIn all these gatherings there is at least one bossy or bad-tempered bird which struts about squawking and attempting to peck those within reach, but rarely catching them. Then when all is quiet they find repose by standing with heads down on one leg as if "at attention,' and continue in this attitude till some disturbance takes place. When these birds leave one part for another distant part their flight is strong, buoyant, direct, and unwavering, but on ordinary occasions it is somewhat devious. They walk and run with the greatest of ease, and not ungracefully. It is a quite common occurrence to see scores of these birds at the Otago Heads or the Kaik, attempting to drag some fish or other animal matter out of the receding tide. In such a work a red cod or other fish is soon torn to pieces and eaten; there is no quarter given, and each one expects to be pursued if he is fortunate enough to tear off a morsel. One bird with a piece too big to swallow flies off to evade pursuit, and if he happens to have more speed than the others will liy direct, while another will attempt to head him off, the bird with the extra weight being gradually worn down and forced to relinquish the much-coveted morsel, when another takes up the piece, and the same performance again takes One would expect such clean, daintylooking birds to be capricious in their choice of food, rather than to be, as they are, scavengers that delight in eating disgorged and putrid fish or in feeding at the mouth of some large drain or creek which drains either a soap factory, tannuery, or by-product plant. In some pans these gulls while waiting i°r the tide to go out will loiter about the anchored boats and launches or on some shed or building, making themselves a nuisance to all owners of craft. ~,.•.„, Very few are able to estimate the services rendered by these dainty birds. Dairy and agricultural farmers have come to regard them as efficient exterminators of myiads of grub-producing insect, whose larvra are a scourge to the crops or grass. I have often watched them following the plough, or, while cultivation was in progress, devouring grass grubs, and on pastures cleaning up tne Australian crickets, which arc a curse in some parts of the Waikato. They often fly some two miles to where grubs or crickets are to be found, hunt for an hour and return to their favourite haunt near the shore, enlivening the beaches and harbours by their irregular movements. The mackerel gull, lays its eggs on almost bare ground, with a few bits ot dry grass or seaweed, in river beds, On the shores of cliffs, and even on solitary rocks in the Otago Harbour. The eggs are yellowish grey, marked with grey and dark brown. There must be a good deal ot intelligence in the mackerel gulls and the birds' habits or traits ren.iy observation. I find it abundantly clear that rhythm plays an important part in their behaviour in regard to tides. 11 anyone takes notice he will see. as I have seen, these gulls always at their feeding grounds before the tide is out, waiting lor dead low water to gather " the early worm " left by the slack water. .