COBBLER OR TAILOR?
The disagreement between the popular and the scientific name of the tailor-bird (Orthotomus sutorius) must, I suppose, be attributed to the fact that the average ornithologist is not learned in the Classics. I freely admit that I did not notice the discrepancy until it was pointed out to me. Orthotomus sutorius means, not the tailoring, but the cobbling Orthotomus. It was, I believe, Forester who, considerably over a century ago, gave the bird the specific name which it now possesses, or rather the allied name, sutoria. If he wrote this in mistake for sartoria, the error was a stroke of genius, since the bird should certainly be called the cobbler rather than the tailor. The so-called sewing of the nest is undoubtedly a great performance for a little bird that does not possess a workbox. Nevertheless, if the dirzie who squats in the verandah did not work more neatly than the tailor-bird he would soon lose his place. Orthotomus sutorius does not sew leaves one to another, it merely cobbles them together, much as the "boy" cobbles together the holes in his master's socks.
When last I wrote about the tailor-bird, I had honestly to admit that I did not know how the bird did its work.
My attitude towards its sewing was then that of the child who sings -:
Twinkle, twinkle, little star, How I wonder what you are !
To-day I can boast with the learned astronomer -:
Twinkle, twinkle, little star, Now we all know what you are ! for I have found out how the bird does its sewing.
Some months ago Mr. G. A. Pinto, a very keen ornithologist, informed me that a tailor-bird built regularly every year in the verandah in front of his drawing-room window. He told me that he had never thought of watching the stitching operation, and was much surprised when I informed him that, so far as I knew, no one had ever observed the complete process. He said that as the bird would undoubtedly begin building shortly, he would follow the whole process from the other side of the window. He was as good as his word. It is thanks to his patient watching that I am in a position to pen this article. Towards the end of May the hen tailor-bird began "prospecting" for a likely site, for the hen alone works at the nest, and selected a Dracaena plant on the left-hand side of the entrance to the verandah. One of the leaves of the plant was so curved that its terminal half was parallel with the ground. Upon this she commenced operations. The first thing she did was to make with her sharp little beak a number of punctures along each edge of the leaf. In this particular case the punctures took the form of longitudinal slits, owing to the fact that the veins of the Dracaena leaf run longitudinally. In leaves of different texture the punctures take other shapes. Having thus prepared the leaf, she disappeared for a little and returned with a strand of cobweb. One end of this she wound round the narrow part of the leaf that separated one of the punctures from the edge ; having done this, she carried the loose end of the strand across the under surface of the leaf to a puncture on the opposite side, where she attached it to the leaf and thus drew the edges a little way together. She then proceeded to connect most of the other punctures with those opposite to them, so that the leaf took the form of a tunnel con¬verging to a point. The under surface of the leaf formed the roof and sides of the tunnel or arch. There was no floor to this, since the edges of the leaf did not meet below, the gap between them being bridged by strands of cobweb. This was a full day's work for the little bird, and more than sufficient to disqualify her for membership in any trade union.
She next went on to line with cotton this cul-de-sac which she had made in the leaf. She, of course, commenced by filling the tip, and the weight of the lining soon caused the hitherto horizontal leaf to hang downwards, so that it eventually became almost vertical, with the tip pointing towards the ground. When lining the nest the bird made a number of punctures in the leaf, through which she poked the lining with her beak, the object of this being to keep the lining in situ. It was Mr. Pinto who first called my attention to these punctures in the body of the leaf. He informed me that he had never seen a tailor-bird's nest in which the lining did not thus project through holes in the leaf, and that when searching for such nests he always looked out for this. My subsequent observations have tended to confirm his statement.
All this time the edges of the leaf that formed the nest had been held together by the thinnest strands of cobweb, and it is a mystery how these can have stood the strain. However, before the lining was completed, the bird proceeded to strengthen them by connecting the punctures on opposite edges of the leaf with threads of cotton. Her modus operandi was to push one end of a thread through a puncture on one edge and the other end through a puncture on the opposite edge of the leaf. The cotton used is soft and frays easily, so that that part of it which is forced through a tiny aperture issues as a fluffy knob, which looks like a knot and is usually taken for such. As a matter of fact, the bird makes no knots; she merely forces a portion of the cotton strand through a puncture, and the silicon which enters into the composition of the leaf catches the soft, minute strands of the cotton and prevents them from slipping.
Every one must have noticed how brittle a dead leaf is. This brittleness is due to the silicon which is deposited in the epidermis of the leaf. When the leaf is green the silicon is not so obvious; it is nevertheless there. Some leaves take up more silicon than others; grasses, for example, contain so much that many will cut one's hand if roughly plucked. I imagine that the tailor-bird usually selects for her nest a leaf or leaves in which there is plenty of silicon. Thus the bird does not make a knot as is popularly supposed, nor is there any necessity for her to do so. Sometimes the connecting threads of cotton are sufficiently long to admit of their being passed to and fro, in which case the bird utilises the full length.
I may mention that when the nest, the building of which I have attempted to describe, was about three parts finished, Mr. Pinto noticed that the bird had ceased to work at it. He was surprised and disappointed. He then discovered that the little builder was at work on a Dracaena plant on the right-hand side of the entrance to the verandah, not two yards distant from the first nest. He was much astonished at the strange behaviour of the bird, and still more so when, the next day, she had resumed work at her first nest, which she completed, leaving the second unfinished at the stage when the punctures had been made and the edges of the leaf drawn together by strands of cobweb. Presently an explanation of the bird's unusual behaviour occurred to him. His dog which, ordinarily, is chained up at one end of the verandah, was, on the day the tailor-bird left her first nest, fastened up in the middle of the verandah, so that the bird while working at her nest would be within its reach. She evidently objected to this, so began a new nest; but next day, when the dog had been removed, she returned to her more advanced nursery. This accident of chaining up the dog for one day in the middle of the verandah was particularly fortunate, for it enabled me to examine carefully a nest in an early state of construction.
This account must, I fear, close with a tragedy. When the little cobbler had been sitting on her eggs for about ten days one of the garden coolies broke them, out of mischief, and thought he had done a clever thing. He is now a sadder if not a wiser rascal!