holes in banks, rocks, or trees, or construct domed nests. If we take
the colours of the female goldfinch, bullfinch, or blackbird, as a
standard of the degree of conspicuousness, which is not highly
dangerous to the sitting female, then out of the above forty birds the
females of only twelve can be considered as conspicuous to a dangerous
degree, the remaining twenty-eight being inconspicuous. (18. I have
consulted, on this subject, Macgillivray s British Birds, and though
doubts may be entertained in some cases in regard to the degree of
concealment of the nest, and to the degree of conspicuousness of the
female, yet the following birds, which all lay their eggs in holes or
in domed nests, can hardly be considered, by the above standard, as
conspicuous: Passer, 2 species; Sturnus, of which the female is
considerably less brilliant than the male; Cinclus; Motallica boarula
(?); Erithacus (?); Fruticola, 2 sp.; Saxicola; Ruticilla, 2 sp.;
Sylvia, 3 sp.; Parus, 3 sp.; Mecistura; Anorthura; Certhia; Sitta;
Yunx; Muscicapa, 2 sp.; Hirundo, 3 sp.; and Cypselus. The females of
the following 12 birds may be considered as conspicuous according to
the same standard, viz., Pastor, Motacilla alba, Parus major and P.
caeruleus, Upupa, Picus, 4 sp., Coracias, Alcedo, and Merops.) Nor is
there any close relation within the same genus between a
well-pronounced difference in colour between the sexes, and the nature
of the nest constructed. Thus the male house sparrow (Passer
domesticus) differs much from the female, the male tree-sparrow (P.
montanus) hardly at all, and yet both build well-concealed nests. The
two sexes of the common fly-catcher (Muscicapa grisola) can hardly be
distinguished, whilst the sexes of the pied fly-catcher (M. luctuosa)
differ considerably, and both species build in holes or conceal their
nests. The female blackbird (Turdus merula) differs much, the female
ring-ouzel (T. torquatus) differs less, and the female common thrush
(T. musicus) hardly at all from their respective males; yet all build
open nests. On the other hand, the not very distantly-allied
water-ouzel (Cinclus aquaticus) builds a domed nest, and the sexes
differ about as much as in the ring-ouzel. The black and red grouse
(Tetrao tetrix and T. scoticus) build open nests in equally
well-concealed spots, but in the one species the sexes differ greatly,
and in the other very little.
Notwithstanding the foregoing objections, I cannot doubt, after reading
Mr. Wallace s excellent essay, that looking to the birds of the world,
a large majority of the species in which the females are conspicuously
477