BLACK-BILLED CUCKOO. 
Black-billed The Black-billed Cuckoo is distinctly a 
puekop more musical bird, although his song em- 
CoccyZzus ery- 
throphthalmus braces but two well-defined tones only ona 
L. 11.75 inches Of which is commonly prominent. In 
May 15th appearance he resembles the foregoing 
species, with a few minor differences. Upper parts 
brown-gray with a greenish iridescence ; the tail feath- 
ers not black and only narrowly tipped with white; 
under parts dull white ; bill entirely black. The nest is 
similar to that of the preceding species, but the egg is a 
deeper tone of green-blue. This bird is also a wholesale 
destroyer of the tent caterpillar ; he is distributed farther 
north than the preceding species. 
The most distinct feature of this Cuckoo’s song is the 
rhythmic recurrence of the rest. This is a thing as 
easily recognized by the unmusical as the musical lis- 
tener. When one hears a series of rhythmically inter- 
rupted monotones coming up from the meadow, there 
can be no doubt about the singer, it is the Black-bill ! 
No other bird sings exactly that way. I can perfectly 
demonstrate the principle by a series of dots to repre- 
sent the notes, thus: 2. «2 «2 ec e+ e+ But the 
bird does not always stick to couplets, «2. +--+ ses 
nor does he particularly favor triplets, ..+-+ o-+. e+e 
nor is he unmindfu! of the fact that even in music ‘* va- 
riety is the very spice of life” 2. «se «ee e+ cee ees 
It is apparent, then, that however irregular the number 
of the notes, the principle of rhythmic pause remains 
irrefragable. So perfectly timed is this pause, that upon 
22108 Andante, Uae Ritarde pes 
3 
i] : 
ye ET ee id Dd ae Ba Oe ee 
Nba o> lea oigede tte acteeetteeaU 
irae ep ee 1 ee ee ee 
a 6 a ee ee OR a ES 
setting the metronome to the song the bird will be 
found singing with almost mechanical accuracy. There 
is also another well-marked feature of the Cuckoo’s song. 
Listen attentively to the quality of a single tone and it 
will at once become apparent that it is accompanied by 
an undertone (properly an overtone) of a more or less 
17 
