CONSPICUOUS COLOURS. 
227 
Co. 
Ap - XVI. 
r blackness can hardly serve in any case as a pro- 
e °tion ' tTT ‘ ’ ’ 
. 1 
s and in others in which both sexes are black, 
_ 1 1 _ , 
6 beak or skin about the head is brightly coloured, 
I)* 1 ' ^ le contras t thus afforded adds greatly to their 
e auty ; we see this in the bright yellow beak of the 
blackbird, in the crimson skin over the eyes of 
jj . black-cock and capercailzie, in the variously and 
th. 
.^ghtly-coloured beak of the Scoter-drake (Oidcmia), 
0 ,, red beak of the chough ( Corvus graculus, Linn.), 
bhe black swan, and black stork. This leads me to 
>ark that it is not at all incredible that toucans may 
^ e the enormous size of their beaks to sexual selec- 
° n > for the sake of displaying the diversified and vivid 
'pes of colour, with which these organs are oma- 
j, fJU ted . 62 The naked skin at the base of the beak and 
n d the eyes is likewise often brilliantly coloured; 
tlj, VIr - Gould, in speaking of one species , 63 says that 
„ e colours of the beak “ are doubtless in the finest 
most brilliant state during the time of pairing.” 
^ 6l ' e is no greater improbability in toucans being 
l ' u mbered with immense beaks, though, rendered, its 
as possible by their cancellated structure, for 
l! °bject falsely appearing to us unimportant, namely, 
e display of fine colours, than that the male Argus 
*>2 -w 
Ni’sfactDry explanation has fiver been offered of the immense 
b u ,) " n<1 r still less of the bright colours, of the toucan’s beak. Mr. 
St ti ^ • rile Naturalist on the Amazons,’ vol. ii. 1863, p. 311) slates 
baiifi y use tlieir h 0a k for reaching fruit at the extreme tips of the 
“M v * B ’ and likewise, as stated by other authors, for extracting eggs 
'V | hg birds from the nests of other birds. Bui, as Mr. Bates admits, 
“ tll| “can scarcely be considered a very perfectly-formed instru- 
di' 11 tor the end to which it is applied." The great bulk of the beak, 
til,. ?' vn ky its breadth, depth, as well as length, is not intelligible on 
s» if' v > that it serves merely as an organ of prehension. 
t&mphastos corinotus, Gould’s ‘ Monograph of Ramphastidso.’ 
Q 2 
