86 
ANIMAL CURIOSITIES 
Equally curious is the beak of the open- 
bill, which displays a cavity or gap between 
the closed mandibles, the utility of which is 
unknown. 
Although the different sexes of birds are 
often denoted by the varying colour of their 
plumage, yet in the huia bird of New Zealand 
we have an example in which the male and 
female may be distinguished by the form of 
the beak alone, that of the former being of 
an inconspicuous, short, thick, and slightly 
curved type, while that of the latter is both 
slender and long, and arched downwards in 
a very prominent manner. 
So far we have reviewed some of the more 
curious types of birds that arrest attention 
on account of the large size or unusual forma¬ 
tion of their beaks, but -there still remain to 
be mentioned certain members of the feathered 
folk in which the bill is nearly non-existent. 
Foremost among these is the night-jar, in 
which the beak is reduced to little more than 
a pair of knob-like excrescences situated at 
the front of the mouth. As, however, the 
bird feeds entirely upon insects and beetles 
which it captures on the wing as it flies with 
wide-open mouth, the lack of a more powerful 
beak is in no way detrimental to its welfare. 
Attention must also be drawn to a group 
