NATURE NOTES

Evening Post, Volume CXXX, Issue 72, 21 September 1940, Page 9

NATURE NOTES

(By E. H. D. Stidolph.)

BIRD SONG

ARE SOME SPECIES SINGING

LESS?

Are some species of birds introduced to New Zealand singing less than formerly? A friend remarked to the writer a week or two ago that in his opinion the blackbird is not singing as much now as it did years ago, and by a strange coincidence, a letter from Mr.,J. Morris, of Charleston, Westport, which came to hand a day or two later^ raised the same question. The latter correspondent observed: "In regard to the blackbird I think, during the past thirty years, this bird has been singing less and less each year. I think if young bh'd-lovers take a hint from this statement, in the years to come they may see the day when the blackbird has ceased to sing altogether. Forty-five years ago I consider the blackbird sang more often, louder, and better than it' dbes today, and that in this period its notes have certainly altered considerably. The song thrush is as good as ever. .< . The skylark and the goldfinch of today do not appear to sing as often as they, did years ago. Opinion, on this subject from bird-lovers may prove interesting." SUBJECT OF MANY ASPECTS. A proper study of bird song raises innumerable points that require eluci- . dation, an object that can be achieved only after some years of patient observation and recording. There are no end of aspects touching this subject, bearing on the normal song • period; the effect of weather conditions; the variation, if any, between majted and unmated birds^ whether song occurs in hours of daylight or darkness or both; whether it is imitative, what phases it contains, whether it is uttered from the same perch or series of perches, whether from the ground or in flight, 'the relation to nesting and to territory, the reaction to members of the same or opposite sex, and many other, points that arise ta an inquiring mind. Anyone making an investigation would do well to confine the scope .of inquiry to one or two species, records of which would be required for several years before , any conclusion could be reached. Probably the most explicit way in which the data accumulated can be presented is by a graph. In Britain more and more attention has been given in recent years to a study of bird song in its relationship to the life of birds generally, but much more information has to be collected before any definite conclusions can be reached. SILENT MALES?: < In an interim report on the British i Trust for* Ornithology's inquiry into the song periods of certain, species, it was- suggested that some males never sing. Referring to this matter in a recent issue of "British Birds," a writer points out that though some individuals seem to sing rarely or not at all, to confirm this it is necessary to listen in the bird's territory for an hour before dawn till one 7 or two hours after sunset. Song-periods in the breeding season, he states, should be considered in conjunction with the male's breed- . ing activities,, especially,.,if relative song-periods of species! are studied, for not only may the period be prolonged by records obtained entirely from unmated males or from those who have failed to complete or begin the cycle, but also the song-persistency of unmated or unsuccessful males may vary from species to species. . This observer, after giving some data retentive'to the singing of the song thrush and the blackbird, gives a summary of his investigations, which suggest, he states, that males which are biologically most efficient, because of that efficiency are relatively silent. Thus, especially when a male is holding an isolated territory and has a mate, the epigamic and territorial stimuli for song are so slight that he may rarely sing during the hours of full daylight. NOTES IN COMMON. Some attention to bird song in New Zealand has been paid by Mr. Johannes C. Andersen, who has devoted a volume to this subject. Although the greater part of his book is occupied with notes about the songs of native birds, reference1, is also made to the songs of certain introduced species, including the blackbird, which, with the song thrush, Mr. Andersen reminds us, is considered the best singer of its family. He observes that the blackbird and the song thrush have so many notes in common that he is unable to say, from the song alone, the singer is a thrush or a blackbird. Moreover, as the blackbird nearly always secludes himself when singing in a thicket, Mr. Andersen says he.has rarely seen this species singing and in consequence he is unable to record any of that bird's practice notes. Owing to the similarity in some of the notes of these two? birds and to the more retiring habits of the blackbird, it is possible that it actually sings more than is thought to be the case, especially as, in marked contrast, the song thrush almost invariably selects a prominent perch from which to sing. It can be appreciated, therefore, that the study of bird' song is one that needs to be taken up carefully and systematically in order to eliminate the possibility of wrong conclusions. NOISY BLACKBIRD. There is no question that the blackbird is seldom heard singing, though, -as has been pointed out, there is considerable variation among individual birds. However neglectful it may be of its song, it is, all the same, at certain periods of the year, one of the noisiest birds of our gardens, especially when' about to retire for the night. On these occasions a^ blackbird is sometimes a very noisy bird, giving voice to a series of loud cacklings or a continuous muttering of "mik." The clamour of its alarm note is known to all residents, even to the most' unobservant. Occasionally, it is to be heard in the dead of night, when the bird has apparently been disturbed in its roosting place. In New Zealand, as elsewhere, the song thrush is an indefatigable singer and easily carries oft' the honours compared with its near relative. To the writer, the blackbird has always appeared a casual singer, not seeming to care very much about its vocal efforts, whereas the song thrush seems to put vital energy into its song, which ring's out far and wide. Perhaps some readers of this column may have views on the points raised regarding the belief that the blackbird ' in New' Zealand is .losing its inclination to sing. _____________