Brewster on the Prothonotary Warbler. 157 
a simple peet, tweet , tweet, tweet, given on the same key throughout. 
Often when the notes came from the farther shore of a river or pond 
we were completely deceived. On more than one occasion, when a 
good opportunity for comparison was offered by the actual presence of 
both birds at the same time, we found that at the distance of several 
hundred yards their notes were absolutely undistinguishable ; nearer 
at hand, however, the resemblance is lost, and a ringing, penetrating 
quality becomes apparent in the Warbler’s song. It now sounds like 
peet, tsiveet , tsweet, tsweet, or sometimes tweet, tr-meet, tr-sweet , tr-siveet. 
When the bird sings within a few yards the sound is almost startling 
in its intensity, and the listener feels inclined to stop his ears. The 
male is a fitful singer, and is quite as apt to be heard in the hot 
noontide or on cloudy days, when other birds are silent, as during 
the cool morning and evening hours. The ordinary note of alarm 
or distress is a sharp one, so nearly like that of the Large-billed 
Water Thrush ( Siurus motacilla) that the slight difference can only 
be detected by a critical ear. When the sexes meet a soft tchip of 
recognition common to nearly all the Warblers is used. Jn addition 
to the song above described the male has a different and far sweeter 
one, which is reserved for select occasions, — an outpouring of the 
bird’s most tender feelings, intended for the ears of his mate alone, 
like the rare evening w’arble of the Oven-Bird ( Siurus auricapillus). 
It is apparently uttered only while on the wing. Although so low and 
feeble as to be inaudible many rods away, it is very sweet, resem- 
bling somewhat the song of the Canary, given in an undertone, with 
trills or “ water-notes ” interspersed. The flight during its delivery 
is very different from that at all other times. The bird progresses 
slowly, with a trembling, fluttering motion, its head raised and tail 
expanded. This song was heard most frequently after incubation 
had begun. 
In general activity and restlessness few birds equal the species 
under consideration. Not a nook or corner of his domain but is 
repeatedly visited through the day. Now he sings a few times 
from the top of some tall willow that leans out over the stream, 
sitting motionless among the yellowish foliage, fully aware, per- 
haps, of the protection afforded by its harmonizing tints. The next 
moment he descends to the cool shades beneath, where dark, coffee- 
colored water, the overflow of the pond or river, stretches back 
among the trees. Here he loves to hop about on floating drift-wood, 
wet by the lapping of pulsating wavelets ; now following up some 
