THE PERCHING BIRDS. 67 



and bobbing motion of the head. Every movement 

 suggested an aquatic life ; and while so engaged the 

 only sound they make is a single, short, sharp chirp 

 when alarmed. But there are occasions when all 

 this is changed. In the early summer it finds time 

 to leave the water's edge and go deeply into the 

 swamps, where the undergrowth is almost impene- 

 trable. It moves amid this tangle with the same 

 ease that marked its progress on the pebbly beach 

 or over the yielding mud-flat. But when in the 

 woods it does something more than merely chirp. 

 In an extensive tide-water swamp, where I have often 

 found these birds, I have heard them sing, seldom in 

 light of day, but often in the gloaming. Clear, flute- 

 like notes in rapid succession were poured forth, then 

 shriller and wiry ones, and these followed by a trill 

 that slowly died away. The song is not always the 

 same, and probably no two individuals perform it 

 quite alike. To my hearing, it bears no resemblance 

 to the evening song of the oven-bird. The nests of 

 the two water-thrushes are always on the ground, 

 and those of the short-billed species that I have seen 

 were composed almost wholly of dried sphagnum 

 and lined with fine grass. 



A family of warbler-like birds, yet with character- 

 istics quite their own, that are strictly arboreal, and 

 so, naturally, insect-eaters, are the plainly colored, 

 but neat, active, musical Vireos, or Greenlets. The 

 facts that they are greenish-olive above and yellow 

 or yellow- white below, and have rather stout, hooked 

 beaks that seem better adapted than a warbler's bill 

 for holding on to big insect game, these points will 



