Chap. XV. 
DEVELOPMENT OF SPUES- 
163 
females, as well as the males, possess well-developed 
spurs. Are we to infer from this fact that they con- 
struct a different sort of nest, not liable to be injured 
by their spurs, from that made by their nearest allies, 
so that there has been no need for the removal of their 
spurs ? Or are we to suppose that these females especi- 
ally require spurs for their defence ? It is a more pro- 
bable conclusion that both the presence and absence of 
spurs in the females result from different laws of inherit- 
ance having prevailed, independently of natural selec- 
tion. With the many females in which spurs appear 
as rudiments, we may conclude that some few of the 
successive variations, through which they were deve- 
loped in the males, occurred very early in life, and were 
as a consequence transferred to the females. In the 
other and much rarer cases, in which the females pos- 
sess fully developed spurs, we may conclude that all 
the successive variations were transferred to them ; and 
that they gradually acquired the inherited habit of not 
disturbing their nests. 
The vocal organs and the variously-modified feathers 
for producing ^ound, as well as the proper instincts 
for using them, often differ in the two sexes, but are 
sometimes the same in both. Can such differences be 
accounted for by the males having acquired these organs 
and instincts, whilst the females have been saved from 
inheriting them, on account of the danger to which 
they would have been exposed by attracting the at- 
tention of birds or beasts of prey? This does not 
seem to me probable, when we think of the multitude 
of birds which with impunity gladden the country with 
their voices during the spring.® It is a safer conclu- 
® Daines Barrington, however, thought it probable Phil. Transact.’ 
1773, p. 164) that few female birds sing, because the talent would have 
, M 2 
