1SG 
SEXUAL SELECTION: BIRDS. 
Part 
Although many young birds belonging to vari° 1 ' 
orders thus give us a glimpse of the plumage of t>® 
remote progenitors, yet there are many other birds, 
dull-coloured and bright-coloured, in which the vo 1 ® 
closely resemble their parents. With such species 
} r oung of the different species cannot resemble each 0®^ 
more closely than do the parents ; nor can they P rese ']{, 
striking resemblances to allied forms in their ad' 1 
state. They give us but little insight into the phi® 1 ?, 
of their progenitors, excepting in so far that when 1 j 
young and the old are coloured in the same gen® 1 
manner throughout a whole group of species, it is V t0 ' 
bable that their progenitors were similarly coloured- 
We may now consider the classes of cases or rU ^ 
under which the differences and resemblances, bet"’ 0 ^. 
the plumage of the young and the old, of both seS eS . ^ 
of one sex alone, may be grouped. Eules of this 
were first enounced bv Cuvier; but with the prOr 1 ’,:. 
of knowledge they require some modification and a®!’,^ 
fication. Tin's I have attempted to do, as far ‘ 
extreme complexity of the subject permits, from ® ^ 
mation derived from various sources; but a full eS 
on this subject by some competent ornithologhj { 
much needed. In order to ascertain to what ^ 
each rule prevails, I have tabulated the facts gi veIJ ., ( ;j 
four great works, namely, by Macgillivray on the 
of Britain, Audubon on those of North America, -T® j 
on those ol India, and Gould on those of Austral®' ^ 
may here premise, firstly, that the several cases or ^ 
jjOi 
► * JJ * 
raduate into each other ; and secondly, that when 
to resemble their parents, it 
young are 
said 
meant that they are identically alike, for their 
are almost always rather less vivid, and the t’ ea 
are softer and often of a different shape. 
