caused by the change of shape in the singing aperture from 
that required for the i (ee) to that required for the oo so 
that the interval of the slur will under ordinary circumstances 
depend upon the vocalization, the purer the ee and oo sound of 
the tin ( tee-oo) being, the wider the interval, till the full differ¬ 
ence of natural vowel-pitch is made; as the alteration in the 
shape of the aperture brings the ee sound nearer oo, the interval 
becomes less. At Kapiti phrases were noted in January 1917 
consisting almost altogether of this vocalization, as in ( 2 )' 
The phrase was varied by the central very staccato tin being 
repeated a varying number of times, two, three, or more. Every 
phrase would be repeated twice or more, the three concluding 
notes being of a strange, mellow, bell-like quality, vocalized 
hoo-ee-oo, or hum, like the call of the liuia. Variations in the 
interval of the slurred tin have been noted as small as a semitone, 
and as much as an octave: at times no interval can be detected, 
as if the vocalization were simply tehoo. 
In the common phrase (1) the tiu tin may be dropped, and a 
continuation added as in (3), where a whistling opening is con¬ 
cluded with two deliberate bell-like notes. The whole was 
uttered in a second and a half, perhaps less. It must again be 
stated that all variants noted were heard more than once; in 
many cases they were heard scores of times before being finally 
recoided. The notes often vary in force, as shown in ( 4 ), where 
the pitch of the softly uttered e was very baffling. The phrase 
v as sung by a bird that came flying with the call tiu tiu tiu, 
and settled in a tree close by, beginning at once to search for 
insect prey. The song, taking a little over a second, was clear 
and bright, and as usual constantly varied in pitch. In the year 
this was taken, 1912, it was noticeable that at times the call was 
preceded by two very light notes, these taking the place of the 
opening tiu tiu. In (5) an extraordinary high note was intro¬ 
duced, it being dropped an octave at the close. In ( 6 ) the accent 
^as on the first note, and on the following odd notes right 
through. This was the common call on Kapiti in 1917, the notes 
I' 111 ? e ^ ear whistles, eight or ten to the second, the longer con- 
c uding notes being clear, open, and full, sometimes flute-like. 
