418 THE ZOOLOGIST. 



possible sign of its strong wish to take its partner's place on the 

 nest. All this while, however, the sitting bird sat on, and it 

 was not till the petitioner had made several voyages right in to 

 the bank, that it at last came off, and I saw it slide down the 

 steep place, just pushing its body forward, to do so, without 

 rising. After the slide both birds were, for a few moments, 

 hidden behind the two large stones I have spoken of, then one 

 swam out, and the other, shortly afterwards, leapt up the bank 

 and took its place on the nest. I again noticed that it stood 

 over the nest before sinking down on it, and it reached it, I am 

 sure, in this attitude. The bird that had been relieved, or 

 rather importuned into leaving, now swam out a little from 

 the islet, and began to preen itself, flap its wings, and so on, 

 before diving off (as I supposed it would do, after having sat all 

 the night), when all at once, and to my great surprise, I saw the 

 one that had but just commenced sitting, and had seemed so 

 much to want to, swimming out from the stones, and keeping 

 the pair, now carefully distinct, which was easy, I can say as a 

 certainty, that when, in another few minutes, the nest was once 

 more occupied, it was not by this same one again (as under 

 the circumstances one might have expected it would be), 

 but by its partner, whose place it had taken only for a quarter 

 of au hour, or, to be accurate, seventeen minutes. I suppose it 

 was the female, and that she can hardly keep away from an egg 

 now well on towards hatching, but no one who had seen the 

 male pleading, as it were, to be allowed to go on, could have 

 thought that, of his own initiative, he would have come off 

 again so soon. He did not go right away, however, but was still 

 in evidence at 9, when I had to leave, though at some distance 

 out in the lake. In spite of his short turn, it is plain that he, 

 as well as the female, is very interested in the incubation. I 

 have mentioned that, for a moment or two before the first 

 change, both birds were out of view, so that it cannot be actually 

 proved that the one who then came off the nest did not 

 immediately go back on to it again, in which case there would 

 not have been a change upon it at all. This introduces what 

 may be called a scientific doubt, but, like a good many scientists 

 now-a-days, I have disregarded even graver ones in more impor- 

 tant matters — thought-transference, for instance, und dergleichen. 



