THE MALE RUBY-THROAT. 147 



been near by. After this I went to the edge 

 of the wood, where I could keep an eye 

 upon both trees without being myself con- 

 spicuous. The sentinel spent most of his 

 time in the ash, visiting the apple-tree but 

 once, and then for a few minutes only. I 

 stayed an hour and a half, and came away 

 no wiser than before. The nest, if nest 

 there was, must be elsewhere, I believed. 

 But where? And what was the object of 

 the male's watch? 



My curiosity was fully roused. I had 

 never seen or heard of such conduct on the 

 part of any bird, and the next forenoon I 

 spent another hour and a half in the clear- 

 ing. The hummer was at his post, as he 

 always was. We had never to wait for him. 

 Soon after my arrival he flew to the apple- 

 tree, the action seeming to have no con- 

 nection with my presence. Presently he 

 went back to the ash, and drove out of it 

 two intruding birds. A moment later two 

 iiumming-birds were there, and in another 

 moment they flew away in a direction op- 

 posite to the apple-tree. Here, then, was 

 a real clue. The birds were probably our 

 sentinel and his mate. I made after them 



