NATURE OBSERVATION

Forest and Bird, Issue 56, 1 May 1940, Page 10

NATURE OBSERVATION

(By R. H. D. Stidolph.)

THE NEED FOR ACCURACY IN FIELD WORK

A BIRD-LOVER enjoys every minute of a day spent among the birds in the open, and if the art of observing wild life is tackled in an intelligent way many observations of value may be recorded. In New Zealand, where almost all native birds are protected, it is the most logical pursuit for those whose enthusiasms for our birds finds expression in a desire to become better acquainted with the ways of their feathered friends. A careful observer never causes any distress to, nor unduly disturbs, any bird but is content to watch them and record their habits, working so quietly that on many occasions the birds may be quite unaware of his presence. It is under such conditions that true insight into a bird’s habits is to be gained. Moreover, even dwellers in cities and towns, if they keep their eyes open and their ears tuned into bird calls, may often see something of more than usual interest. It must not be assumed that a city dweller is ill-placed for making observations of that kind. As a case in point, how many of the hundreds of thousands of people who visited the Centennial Exhibition during the birds’ breeding season noticed that both the starling and the sparrow had been quick to seize the opportunity of finding suitable places for nests inside the Exhibition buildings? Every care must be taken when making a record that it is correct in every particular. To ensure this it is necessary to be positive of the identity of the bird and to record only exactly what takes place. The value of a record is at once destroyed if mere assumption is allowed to appear as an event of fact. It is far better to refrain from putting forth any observation if there is any doubt as to its correctness. It is essential always to place

first and foremost the safety of the bird. Never do anything tljat imperils the safety of a bird or its nest. Do not under any circumstances touch a nest or the eggs, as some birds will readily desert them if they are handled, and in any case it is quite unnecessary to interfere with them. In making an examination of a nest, a mirror fixed on to the end of a stick is of great assistance and enables the contents of a nest to be seen without jeopardising the safety of the structure by climbing to it, especially when the nest is placed on a thin branch. If you are watching a nest, do so from a convenient distance, so that your presence does not disturb the adult birds; and if you find the birds will not return, even when you are a safe distance away, retire altogether rather than endanger the young or eggs. Remember that as a bird lover and a bird observer your job is to check vandalism and to save the birds from any injury.

Apart from the breeding habits, many valuable observations of the habits of birds may be made; but the best work is obtained when you work to a definite plan and in collaboration with other bird watchers. For instance, concentrate on one particular area or one particular species. Take careful and full notes of everything you see, such as the first arrival of a bird, how many birds inhabit the area, when they start to sing, when the breeding season starts and ends, their behaviour in respect to territorial rights and to other species, how they are affected by the weather, how many broods are reared in a season, and a thousand and one other points that arise, and at the end of a year a valuable mass of data is accumulated. The same thing extended over a number of seasons allows comparisons and deductions to be made that may be of considerable value. Although much good work can be accomplished without binoculars, a good pair of glasses is almost indispensable. They enable an observer to see many intimate little happenings in a bird’s life that would otherwise be missed and in many cases to identify positively a bird that under ordinary circumstances would not be possible. Prismatic binoculars of six or eight magnification are the most suitable for general all-round work. It is as well to remember that laboratory work, unless supported by accurate field observations, loses much of its value. It is possible in some cases to be misled by placing reliance on laboratory conclusions to the exclusion of other evidence. Similarly, a casual observer may make a gross mistake, as is evidenced by an instance in which a poultrykeeper in Australia, seeing a hawk perched in a tree over his chicken runs, at once concluded that the hawk had designs on his poultry. The bird was shot but when its stomach was opened up the crop was found to be crammed full of large caterpillars and grubs. Because a bird is seen in a wheat field crop it must not be concluded that the bird is feeding on the grains; it may be destroying injurious insects that threaten the very existence of the wheat. These instances emphasise the great need for care in making bird observations and at the same time give some idea of the scope offered in the field for accurate work. No native or introduced bird in New Zealand has been studied systematically and there is an almost virgin field of investigation open for bird observers

in this country who have the time and inclination to undertake work on these lines. One of the most important aspects of bird observation work is that which concerns itself with recording evidence of the depredations of enemies, such as stoats, ferrets, weasels, cats, rats, dogs, or opossums. Unfortunately, a mass of misstatements exist about many incidents of bird life, one of the most glaring of which, in recent months, being that the hedgehog had wrought so much devastation among the skylark as to cause this bird’s almost total disappearance in some areas. As a matter of fact, in areas known to the writer where the hedgehog is quite common, the skylark remains one of the most numerous of introduced birds.' No one denies that the hedgehog destroys the eggs and young of ground-nesting birds, but the extent of this destruction is a matter which provides a good example for investigation by careful bird observers. The depredations of the weasel tribe among birds have been established beyond doubt; but who had heard of the pukeko being able to hunt and destroy these bloodthirsty little animals until a week or two ago a resident of Charleston, near Westport, reported that the pukeko actually did tackle and vanquish these animals? Here again is another avenue for investigation by birdobservers. Is this a common trait of the pukeko or an isolated case? Are there other birds that give the ferret tribe equally short shrift? The replies to these and many other vital questions can be supplied by birdobservers.