170 
SEXUAL SELECTION: BIKDS. 
PAS*' 
as conspicuous to a dangerous degree, the reiu al 
twenty-eight being inconspicuous . 17 Nor is ther e 
ii> 
— x - ip 
close relation between a well-pronounced differcD (1 , , 
e of 1 
colour between the two sexes, and the nature 01 , 
nest constructed. Thus the male house-sparrow (/ u 
domestieus ) differs much from the female, the ^ 
trce-spurrow (P. montanus) differs hardly at all, 
both build well-concealed nests. The two sexes ol ^ 
common fly-catcher (Muscicapa c/risola) can Jiard-I} 
distinguished, whilst the sexes of the pied fly-c* 1 ^, 
(M. luduosa) differ considerably, and both build in llP ,j l , 
The female blackbird ( Turdus merula) differs 
the female ring-ouzel (T. iorquatus) differs 
and the female common thrush (T. mmicus ) 
at all from their respective males ; yet all build 
nests. On the other hand, the not very ^ 
allied water-ouzel ( Ginclus aquaticus) builds a 
nest, and the sexes differ about as much as in tb e p p 
ol the ring-ouzel. The black and red grouse j|- 
tetrix and T. Scoticus ) build open nests, in equally 
concealed spots, but in the one species the sexes 1 
greatly, and in the other very little. 
Notwithstanding the foregoing objections, I 
doubt, after reading Mr. Wallace’s excellent esS 
17 1 lmve consulted, mi this subject, Macgillivray’s ‘ liri* 'd’ t0 i ;|1 ' 
and though doubts may be entertained in some cases in reg 911 ,|C : 
degree of concealment of the nest, and of the degree of couspi cll ,° l [ )I i] < ' i 
of the female, yet the following birds, which all lay their- egg 9 1,1 
or in domed ne»ls, can hardly he consider! d, according to ft* d 1 
standard, as conspicuous : Passer, 2 species; Sturnus, of 'dj'hcifj 
female is considerably less brilliant than the male; Cinelusi W’V y 
boarula (?) ; Eiithm-ns (?) ; Fruticohi, 2 sp.; Saxicola; 
sp, ; Sylvia., a sp. ; Parus, 3 sp. ; Meristura; Anurthura; 1 ' ft 1 
Sitta; Yunx; Muscicapa, 2 sp. ; Hirundo, 3 sp.; and C-ypse 111 ^#^ 
females ot the following 12 birds may be considered as cowl 
according to the same standard, viz., Pastor, Motacilla alb^v^y* 
major and P. cseruleus, Upupa, Pious, 4 sp., Coracias, Alcedo, » n “ 1 
