THE ACADIAN FLYCATCHER. 323 



THE Bmpidonaces, or Gnat-kings, (as the Greek name signifies), as a 

 group, ofifer peculiar difficulties to the student of birds. Altho separated into 

 many species, the distinctions are so fine and the birds in the hand really look 

 so much alike, that their identification is for a long time, in the experience of 

 every one, involved in doubt and confusion. In the West, indeed, where the 

 habitats of these birds are not yet clearly defined, and where the commonest 

 species has earned the name dMcilis (difficult), the effort to keep up with the 

 little Flycatchers is almost maddening. ' 



The keys to an acquaintance with the four species' which occur in our 

 state, are to be found in the notes, or characteristic cries, which each bird utters, 

 and in the character of the haunts which each affects. The species under con- 

 sideration is the least known of the four. It is found only during migrations, 

 when it is very quiet and very secretive. I have never positively identified it 

 within the state and it appears to be known to only two or three observers. 

 Dr. Wheaton, who was perhaps better acquainted than any one else with the 

 Yellow-bellied Flycatcher, says of its range : "It is seldom found perched near 

 the extremity of limbs watching for or capturing flying insects, but it is gener- 

 ally seen in the midst of a low thicket or fence row, and at the first intimation 

 that it is an object of observation, seeks further concealment by hiding near the 

 ground and remaining motionless. None of the family are such adepts at con- 

 cealment, its habits in this respect resembling those of the Connecticut and 

 Mourning Warblers." 



The ordinary note of this bird is described as "an abrupt pse-ek, almost in 

 one explosive syllable," in which case it cannot be so unlike the familiar cle-otip 

 note of the Acadian Flycatcher. It has, however, a more distinctive call — 

 "a soft, mournful whistle consisting of two notes, the second higher pitched 

 and prolonged, with rising inflection, resembling in a measure chu-e-e-p" (J. 

 Dwight, Jr.). Dr. Wheaton records having heard this longer note on two 

 occasions, but it is rarely heard during the migrations. 



No. 142. 



ACADIAN FLYCATCHER. 



A. O. U. No. 465. Empidonax virescens (Vieill.), 



Synonym. — GreEn-crestbd FlycatchBr. 



Description. — Adult : Upper parts, olive-green, olive, or olive-gray ; wings 

 and tail fuscous ; the wing-barring and edging according to the pattern of the 

 preceding species, but not so yellow — rather inclining to buflfy or gray ; tip of wing 



1 For practical purposes the northern refinement B. traillii alnorum may be disregarded. 



