ON SEXUAL DIFFERENCES. 
33 
lien. After it had been half mui’dered by my older bird 1 dis- 
covered that it was only a small cock. I easily paired np some 
Steel-barred Doves by the form of the bill, but I believe most males 
of this group of birds can be distinguished from the females by 
their prominent foreheads ; in those which show differences in the 
plumage this swollen front is frequently of a distinct colour from 
the forehead of the hen. 
Although the preceding few hints are far from exhaustive, 
they will at anyrate put the buyer in a better position than if he 
had to watch to see whether a bird sang or not before he felt 
happy about it, or even than one who (following the advice some- 
times given by that renowned bird-student, the late Dr. Carl Russ) 
considered it necessary to purchase half-a-dozen or more examples 
in order to ensure getting both sexes. As 1 have already pointed 
out, this result would even then not be at all certain. In the case 
of birds which show sexual difference in the plumage or colour of 
beak, the differences often need to be looked for, asintho Goldfinch, 
the Linnet, the Martinican Dove, in which the violet neck-patch 
is smaller in the hen ; the Bronze Mannikin, in which the metallic 
green patch is smaller in that sex ; the Diamond Sparrow, in which 
the female shows a pale pink line across the base of its crimson 
beak ; the Bicheno Finch, in which the belts across the throat and 
breast are slightly broader in the male than in the female j the 
Showing relative sizes in Male and Female of the Skylark. 
Rosella Parakeet, in which (according to the late Mr. Abrahams) 
the female shows a small spot of green in the crimson at the back 
of the neck ; with many others. 
No difference of colouring should be regarded as unimportant, 
the glossy instead of dull black on the crown, the deeper or less 
ruddy colouring of the upper parts generally, the purer or whiter 
c 
