126 
SEXUAL selection: birds. 
“ having the whole of 
the feathers blue, while 
oth^! 
“ have the eiglit central ones tipped with bea' 1 
tit'" 
green, 
dations have 
It does not appear that intermediate 
een observed in this or the foil** 
In the males alone of one of the Austr 1 ' 1 
parrakeets “the thighs in some are scarlet, in ot )( 
“ grass-green.” In another parrakeet of the ^ 
cases. 
country “some 
individuals have the band across 
“ wing-coverts bright-yellow, while in others the s* , 
“part is tinged with red.” 34 In the United 
some few of the males of the Scarlet Tanager ( T an 
of 
rubra) have “a beautiful transverse band of gl°". 
in? 
“red on the smaller wing-coverts ;” 35 but this vai'i^!. 
pV3 t" 
preserv^! 
#1 
seems to be somewhat rare, so that its 
through sexual selection would follow only 
unusually favourable circumstances. In Bengal 
Honey buzzard (Pernis cristata) has either a £ * 
^ ' slig 11 * 
Off 
rudimental crest on its head, or none at all ; so 
difference however would not have been worth i 
had not this same species possessed in Southern 
crest formed of several 
“a well-marked occi 
“ duated feathers.” 36 A 
The following case is in some respects more int el 'i|, 
ing. A pied variety of the raven, with the head, j 
abdomen, and parts of the wings and tail-feathers " ^ 
is confined to the Feroe Islands. It is not v® r ) i |, 
rr 
erv 1 *, 
there, for Graba saw 
ten living specimens. 
during his visit from eig 
fit 
of 1 i 
Although the characters - m 
variety are not quite constant, yet it has been 
distinguished ornithologists as a J 
1 
by several distinguished ornithologists as a 
species. The fact of the pied birds being pursue 0 
A 156 ' 
M Gould, ‘ Handbook of Birds of Australia,’ vol. ii. p. 32 a u( 
Audubon, ‘ Omitbolog. Biography,' 1838, vol. iv. p. 389. _ 
3f ' Jordon, ‘ Birds of India.,’ vol. i. p. 108 : and Mr. Blyth, 
and Water,' 1868, p. 381. 
