The food-stand has shown me what sparrows are and what they can do. When I set it up I had no wish to feed sparrows, and could not bear to see them devouring all before them in the greedy, systematic way that they have. So I set my wits to work to see if I could not contrive something by which they might be baffled without depriving the tits of their food. It proved more than I could do to prevent any of the sparrows getting any of the food, but I was able to make it more difficult for them, so difficult that only a few could manage it. They differ very much individually: some are far bolder and more enterprising than others, but I have found that some sparrows can do almost anything that a tit can do in the way of acrobatic performances, though not, of course, with the same easy grace. I tried many devices. I had seen somewhere that if food were suspended from a pliable twig only tits would venture to attack it. It didn't take long to prove the fallacy of this idea. The swinging of the net made not the slightest difference to the sparrows; they alighted on it just as readily as if it had been lying on the ground. Then I tried hanging the net at one end of a stick and a movable weight at the other. The stick acted as a balance, and the net went down directly a bird settled on it. This instability frightened the sparrows for a long time, but in the end they got quite used to it. It was the same with many other contrivances that I tried, they answered their purpose for a time, it may be altogether as far as most went, but in every case sooner or later some sparrows learnt to overcome every difficulty, and it struck me that each successive year they seemed to do so more easily, as though they turned the experience of one year to good account in the next. In 1899 I made an apparatus like a windmill, with four arms, and food in a kind of little box at the end of each. The arms, of course, went down directly a bird touched them. This for a long time was effectual, and I had begun to flatter myself that I had solved the problem, but during a hard frost some one or two sparrows overcame their fears and managed to get the fat, and when once they saw it might be done with safety many others learnt the trick. I then complicated the idea into a wheel, with eight arms, and food only at the extreme point of each. This answered so far that no sparrow seemed able to get at the fat from the revolving arm itself as they hung on to it (an easy feat for the tits), but they used to hover opposite the ends of the arms and pick out the food. (Robins did this also.) Independently of its effect in discouraging the sparrows, the wheel afforded much amusement by the antics it imposed upon the tits as they went round and up and down on the arms.