Page:The British Warblers A History with Problems of Their Lives - 4 of 9.djvu/41

 at daybreak. Arriving at my hiding-place, I noticed that something unusual had happened to the nest, and upon examination found that it was very much tilted on one side. In removing the vegetation the previous evening I had carelessly cut away one of the supports, with the result that the weight of the parent bird brooding had brought about a tragedy. I did not then notice that the young were in a state of collapse, so placing some small leaves in the nest as an experiment, I returned to my hiding-place to await the result. As a rule the parents exhibit great anxiety when the nest is in any way interfered with, or even approached, but what impressed me in the present instance was a complete absence of any such excitement. The female arrived with food and gave it to a young one; she then picked up and dropped some of the leaves, but finally left them alone. After a short time the male arrived, fed one young one and carried away a leaf after making some attempt to swallow it. Then followed a long pause, but at last the male returned with food, and settling upon the side of the nest attempted for some considerable time to make the young respond, but without effect. Closer examination then revealed the fact that the young were quite cold and in a state of collapse; and all, in fact, with one exception succumbed while I was still there watching them. The parents now disappeared altogether, but next morning the female was again brooding, and the one young bird had completely recovered, although the dead bodies had not been removed. Returning to the nest a few days afterwards, I found that the birds had deserted and left the solitary offspring to its fate.

Throughout this episode the complete absence of excitement on the part of the parents was remarkable; it seemed as if their anxiety was solely proportionate to the responsiveness of their offspring. For if such an emotion as affection had been present, in no matter how rudimentary a phase of development, it would have revealed itself by an increase, rather than by a decrease, of anxiety with the gradual collapse