IN TOUCH WITH NATURE

Star (Christchurch), Issue 10440, 20 April 1912, Page 8

IN TOUCH WITH NATURE

NOTES ON NATURAL HISTORY IN NEW ZEALAND. (By J. DRUAIMOND, F.L.S., F.Z.S.) The origin and purpose of birds' migrations is attracting more attention as time passes, and it is probable that, with extensive and systematic work, some definite knowledge will be obtainable on this elusive but very fascinating subject. In New Zealand, native birds undertake strange migrations. It has been noted on many occasions that a species may be present in large numbers in a district one season, and after that it may absent itself for a decade. The most obvious theory is that tho birds, in these movements, are influenced by the conditions of the food supplies, nocking where forest berries are ripe and plentiful, and deserting places where tho shrubs and trees have not fruited well. Observations, however, have shown that the theory is not quite satisfying. There is often in the birds' minds something besides a craving for the best food supplies. .An illustration of this was afforded two years ngo, when ffintails were exceptionally plentiful in city and suburban gardens in Christehurch and Dunedin, although the flies and other insects upon which they feed were not unusually plentiful. Hundreds of fautails. apparently, deserted their haunts on tho banks of streamlets and in forest glades to visit gardens in towns and cities, where they had seldom been seen before. Outside the ranks of the landbirds, of course, there are the godwit, the knot, and the sandpiper, which come to New Zealand rrom distant lands, 'and the two cuckoos, which come as regularly as the seasons. Up to the present time inquiries into the movements of these birds have been mainly directed along the lines of speculation and theory. Very few hard facts have been recorded, and a letter from Mr A. Landsborongh Thomson, secretary of the Aberdeen University Birdmigration Inquiry, suggests that some steps of a more practical nature might bo taken in the dominion. Mr Thomson is a son of Professor J. Arthur Thomson, Professor of Natural History at the Aberdeen University, and the author of a large number of not-able scientific works, including, "Outlines of Zoology," "Evolution." " Heredity." and " The Biology of the Seasons." In his letter Mr Thomson says:—"We should be very glad indeed to see you and others who aro on the spot, and are cognisant of the conditions, take np the bird-marking method adopted by our Inquiry. Anything we can do in the way of advice we shall bo only too glad to do." From the information supplied, I learn that the object of the Inquiry is to collect definite information by placing rings on the feot of a large number of birds. It is hoped that % this is done reports will be received of the subsequent movements of a proportion of the marked birds. The rings arc placed on young birds found in tho nests, or on old birds that can be caught without being injured. As the rings are made of aluminium, and are very light, they do not inconvenience the birds. Most of the marking is done in Scotland, and circulars have been widely distributed, requesting any person who captures, kills, or receives news*' of the marked birds to communicate with the Natural History Department of tho University, sending particulars of the locality in which the bird was found, the date, and the number on the ring.

Mr Thomson states- that different methods of marking have been suggested or tried. Amongst these are parchment tied under the tail with silk, thin metal discs'glued to the tail-fea-thers, and indelible stamns on the same feathers. All these methods, however, are clumsy, and are useless as a means of identification after the next moult. Obviously, for convenience and permanence, marks on the feet are best. In early attempts, brass wire or silk ■thread was twisted around a bird's foot, but an inscription of some kind is necessary, and it has been found that nothing is better than an aluminium ring, which is light and durable, and is easily stamped and worked. Information in regard to the capture of a marked bird depends upon the address stamped on the ring. Some rings bear only the marker's initials, but this method is unsatisfactory on account of the difficulty the person who captures the bird may experience in finding the headquarters of the inquiry movement, and it almost completely prevents records being returned from a great distance. Many birds have been found with rings bearing insufficient addresses, but news of their discovery has not been sent to the marker because he could not be found. In the first systematic scheme attempted, young woodcock on the Duke of Northumberland's at Alnwick, Northumberland, bore rings with the letter "N " and fipjures representing the year. A more elaborate method of marking was adopted by the American Bird Banding Association, whose rings have an identification number and the words "Notify 'The Auk.' New York." In the movement with which Professor Thomson and Mr Thomson are associated, the words "Aberdeen University " and a number nro placed on each ring, but on the smaller sizes, used for small birds, the words are contracted to "Aberdeen Univ."

In ringing the birds, the Inquiry has the help of a large number of ladies and gentlemen, who have volunteered their services. Most of them live in Scotland, but some are in England, Wales, and Ireland. A few systematically undertake bird-catching in the winter months, relying chiefly on clap-nets, automatic cage-traps, and other harmless appliances. Many birds, notably gulls on the shore, have been caught at night by means of acetylene cycle lamps, which dazzle and bewilder them. JEach'co-operator is supplied with a list of the common species for which the sizes of rings may be used. With the rings, the Inquiry sends schedules on which particulars of marked birds are recorded. When the schedules are returned to the Inquiry, the particulars they contain are copied into a large ledger. In the present stage of the work no attempt is made to form conclusions. Amongst the results obtained may be mentioned a wigeon duckling, marked on Loch Brora, Scotland! on June 19, 1009. and caught in a duck decoy in Grovingen, North-'east-orn Holland, on September 3, in the same year. A number of young lapwings were marked in the north-east of Scotland in the summer of 1910. Four were caught in Ireland at the end of 1910 or the beginning of 1911, and one was caught at Oporto, Portugal. A song thrush, marked in a nest at Aberdeenshire on June 4, 1910, was ?hot at Loir a, Portugal, on November 6. in the same year. A starling, marked at Edinburgh on March 20. 1911. was four.d si I Saltdalen. Norway, just above the Arctic Circle, on ApVil'2o, 1911. In New Zealand there is an objection to interfering with the rare native birds, but there seems to be no reason why, later on, an attempt should not be made to obtain information in this way in regard to the movements of species that are not protected.