348 Mousley, The Singing Tree. [j u u i y 



(Dendroica coerulescens ccerulescens) in my experience are certainly 

 incessant singers, but the Black-throated Blue differs in many 

 respects from the other two, as he seems to affect denser foliaged 

 trees, and usually sings higher up and is what one might call not a 

 home bird, as I have generally found him to sing much further away 

 from the nest than any of the other Warblers. Still in his case if 

 you are familiar with the sites usually selected for nesting, the 

 'singing tree' or trees will always give you a clue; the only thing 

 you must do is to be somewhat more elastic with regard to the 

 magic circle. In the case of a nest I found this year I could see 

 from the nature of the ground beneath the 'singing trees' that a 

 radius of twenty yards failed to bring me within any site at all 

 likely to hold a nest, the ground being much too open; but by 

 doubling this distance I came within some very dense under- 

 growth, and this I knew from experience was just the very sort of 

 ground a female Black-throated Blue Warbler would be likely to 

 select. I therefore measured out forty yards, but even this was 

 not quite enough, for the nest was eventually found at fifty yards 

 from the nearest 'singing tree,' and ninety yards from the furthest. 

 I mention this case in order to show that there are times when 

 experience and a little common sense must be displayed if good 

 results are to be expected. 



In conclusion it may be stated that in the case of birds that sing 

 in the air such as Prairie Horned Larks, I have found their nests 

 by constantly noticing the male frequenting a certain observation 

 post, usually consisting of a large stone or boulder, although in 

 one case it was actually a tree (see 'Auk,' vol. XXXIII, 1916, 

 p. 285), and from there measuring out the required distance and 

 then walking quietly over the ground, looking well ahead for the 

 female to slip off the nest. Of course it may be necessary to repeat 

 this proceeding several times before she is eventually found at 

 home, but in the meantime there is always the off chance of the 

 nest being discovered quite irrespective of the female whilst quarter- 

 ing the ground. This method can be adopted equally well with 

 Spotted Sandpipers (.let i 'tis macularia) as I found two nests, one in 

 1914 and the other in 1915, the observation post of the male in 

 each case being a heap of stones in a field adjoining ' the marsh.' 



