INTRODUCTION. Xlll 
Gulls, the Herons, and many other large birds, all of which are more or 
less conspicuous and make open nests. In most of these cases, however, 
the birds are well able to defend themselves and their nests from enemies ; 
but the more helpless species (as, for instance, the Sandpipers) seek safety 
for themselves in flight, relying wpon the protective tints of their eggs or 
young. I shall, however, return more specially to this group of birds 
when I treat on that part of the subject which concerns eggs and young 
birds. We now notice a small group of 
Birds in which the male is less brilliant than the female, and which 
nidificate in open nests.—The birds in this group are exceedingly few in 
number, but are nevertheless very interesting. Let us take, for instance, 
the Dotterel (Eudromias morinellus) ; although the differences between 
the sexes of this species are not very striking, they exist, and the female » 
‘is more showy than her mate: or, better still, take as examples several 
of the Phalaropes (Phalaropus), where the females are more brilliant 
in their nuptial dress than the males, the Common Cassowary (Casuarius 
bennettii) or the Emu (Dromeus irroratus), a Carrion-Hawk (Milvago 
leucurus) from the Falkland Islands, an Australian Creeper (Climacteris 
erythrops), and an Australian Goatsucker (Ewrostopodus albogularis), in 
all of which the females are of more decidedly conspicuous colours than 
the males, and the nests are open and exposed. Curiously enough we 
find in all these cases that the male bird performs the duties of incu- 
bation, and in several instances is known to show much more solicitude 
than the female for the young! We have, however, an exception to this 
in the African Ostrich, where the male is more showy than the female ; 
nevertheless he performs the duties of incubation (Sclater, Proc. Zool. 
Soc. 1863, p. 233). The Ostrich has few enemies; and this fact, together 
with that of its peculiar manner of nidification, is probably the reason 
that its plumes have had no check to their present development. It 
is also worthy of remark that the young of probably all these birds, 
instead of resembling the females, as is the case with most species, more 
closely resemble the males, a circumstance which seems to prove abso- 
lutely that sexual selection has been exclusively confined to the female in 
these cases. 
Having now treated of those birds which rear their young in open nests 
we pass on to the second great group, in which the nests are concealed, first 
on our list being 
Birds in which both sexes are brightly coloured and which rear 
their young in holes or covered nests.—QOne of the most striking 
instances in our, for the most part, dull-plumaged northern birds is that 
of the Kingfisher (Alcedo ispida). The male and female are exactly alike in 
colour, and both are adorned with the same refulgent dress. But how 
does Nature shield the sitting bird during the nesting-period ? Why has 
