424 YELLOW-BELLIED FLYCATCHER. 



ground. Alder swamps which are so filled with undergrowtli that it is dillicult to force 

 . one's way through them, are the favorite resorts of these Flycatchers. It is extremely 

 J difficult to detect the presence of these little birds in such places, not only on account of 

 the luxurious vegetation, but. principally Ijecause they are extremely ([uiet, the only note 

 which they utter during the nugrations being a plantive pea given only at intervals and, 

 so low as to be inaudible a few yards distant. I have frequently entered a swamp in 

 which I was certain some of these Flycetchers had taken refuge and have, at first, been 

 iniable to find a single specimen, but upon remaining quiet for a moment, I would hear the 

 low peas in all directions. Guided by the sound of the nearest, I would proceed cautious- 

 ' ]y in.its direction and after a moment's search, would see tht; bird as he sat on some low 

 twig, occasionally launching outward for a short distance to catch a i)assing insect which 

 1 his keen eye had informed him was especially palatable. As long as 1 remained perfectly 

 Still, the Flycatcher would persue his vocation:^ but upon my making t'le slightest move- 

 ment, he would observe me and, giving a quick, upward flirt of liis tail, would tUt 

 ,. silently but with marvelous celerity among the bn»\vn stems of t'le alders, and skillfully 

 wending, his way. through the labyrinth of twigs, vines, and leaves, lie would nlmo.^t in- 

 stantly dissappear. 



' • Although the Yellow-bellied Flycatchers are not sluggish liirds, yet when couqiared 



with the allied species, they appear somewhat inactive. This is due, however to the fict 



that there is little need of them leading a bustling life. The orchards which are the 



I chosen doiUfiius of the Least Flycatchers are also the resorts of hundreds of other l)irds and 



consequently the Flycatchers must keep wide-awake in order to gain alivehood ilnd — they 



do it, as I have endeavored to show. Traills have a less disputed field but still there are 



.enough other avian inhabitants of the locality in which they lintla home to make insects 



itplerably scarce, so these birds cannot be idle; while as I have already described, the x\ca- 



idians usually live in localities where many .species of the feathered tribe are abundant. 



With the birds under consideration, this is quite different tor they occupy spots where but 



few others occur and where insects abound ; tlius they are not obliged to lead a very active 



.'life . and therefore their habits have become decidedly modified l)y the circumstances in 



■which th6y are pLiced. 



The lives which the memliers of this genus lead have apparently had .'<ome ellect on 

 their physical organization. Thus we find that the Least Flycatcher is not oidy the best 

 flier, but it also has th6 best devopment of laryngeal nuiscles, con.secjuently has the most 

 Variety of notes, it bein'g txnderstood, howevef that this partial development does not al- 

 ways mean that the voice of the posse.ssor is the most musical. Next in order follow 

 Traills, difleX'ing. but slightly from the one last desciibed, and then comes the Acadian 

 with weaker laryngeal muscles, for the broncho-trachealis is but slightly developed and 

 consequently the twittering notes are giv^n less fre(juently than by the two preceeding; 

 last in the list conies the Yellow-bellied Plycatcher. The low and shnvly given pea and 

 a gravely randered ke-lick, the first as a single note and the second repeated only at long 

 intervals, are the only sounds wdiich lever heard them utter for they make no attempt at 

 the twittering song. I was not surprised, however, when, upon examining the larynx, I 



