32 Bird-Song : and New Zealand Song Birds 
a narrow slit, the membranous edges “giving” as the sound 
passed: it was not a whistle, or vocalized whistle, like the other 
notes. On this day, too, the 22nd May, a downward interval 
was added, the vocalization again changing,— wee-oo (6) • and 
in (7) a combination took place, of pairs like (1) and an interval 
like (3), the interval containing three semitones instead of two 
m 
e 
e - e . e . e.e.oo 
£> 
* slur 
tlk * *oo.it tik . too.it * wee.tee . tiu ~° 
«/ wee . too . it wee . too . it 
These notes were true whistles, full and rich in quality; they 
gave no trace of localization. The slower notes of (8) were also 
whistles, the higher notes, vocalized, somewhat resembling (5), 
in that they sounded as if forced through a narrow aperture, 
the last four quickening to a vibrato. It is the varying from 
whistle to vocalized note, and the wide range of varied vocaliz¬ 
ation that give the song of the thrush its great variety. At times 
the richness of the vocalization almost equals that of the human 
voice. On the 25th May, the familiar phrase (9) was commenced, 
and now the song developed rapidly; (10) and (11) were intro¬ 
duced, and many other combinations. Up till this day most of 
the new notes could be taken down, those noted being the ones 
most often heard. Combinations of three and four were intro¬ 
duced, but as the only time I had for noting them was during 
a few loitered minutes coming and going, the notes soon became 
too numerous for me to keep count of. The bird had more 
leisure for practice than I for observing;—he would be singing 
before breakfast-time, still singing on my return at luncheon- 
