THE ACADIAN FLYCATCHER. 323 
THE Empidonaces, or Gnat-kings, (as the Greek name signifies), as a 
group, offer 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 difficilis (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. 
y AGADIAN. FLYCATCHER. 
y 
A. O, U. No. 465. Empidonax virescens (Vieill.). 
Synonym.—GREEN-CRESTED FLYCATCHER. 
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 buffy or gray; tip of wing 
1 For practical purposes the northern refinement E. traillii alnorum may be disregarded. 
