COLOR AND SEX 
89 
more commonly than is generally supposed, and by species which do 
not possess pronounced sexual characters of color or plume), will doubt 
the ardor or objects of the suitor; but it seems probable that the effect 
of such display is to stimulate the female to the point of accepting 
rather than of selecting a mate. It should not be forgotten, however, 
that if this theory be true the male which breeds in immature plumage 
(e. g. Orchard Oriole; Redstart) is placed at a distinct disadvantage. 
Wallace (’91) attributes gay colors and showy plumes to the action 
of the surplus vital energy which, because of a bird’s perfect adaptation 
to its environment, can expend itself in the production of brilliant 
colors and ornamental appendages without endangering their owner; 
but in this connection we should recall that when, as with the Phalar- 
opes, the male plays the part of the female, incubating unaided by her, 
then it is the female that wears the brighter colors. 
Thayer, without positively committing himself on the subject of 
sexual coloration, contends that, whatever be the minor uses of the 
distinctively male costumes, their main function is for the purposes of 
concealment; but it is difficult to believe that the male of the Red- 
winged Blackbird, Bobolink, Scarlet Tanager or Lark Bunting, for 
example, is as protectively colored as his dull-plumaged mate, which 
lives in the same environment. If, however, his brighter colors increase 
his chances of death, there must be born a greater number of males than 
females, to offset the higher mortality. 
Again, it has been suggested that it is only the female’s plumage 
which has an especial significance, the task of incubation requiring in 
her a concealing coloration which will protect the contents of the nest 
as well as herself. The whole subject is as attractive as it is difficult. 
It should be studied in connection with other secondary sexual char- 
acters of which a synopsis from “ Bird-Life” is appended: 
Synopsis of the Secondary Sexual Characters of Birds 
Size 
I. Structural 
( Male larger than female (usual). 
(Female larger than male (rare). 
Plumage 
Color 
| Male brighter than female. 
( Female brighter than male (rare). 
( Assumption of plumes, ruffs, crests, trains, etc.; 
special modification of wing- and tail-feathers. 
a. Worn by male alone. 
b. Worn by both sexes. 
{ Sole or greater development in male of brightly colored 
bare tracts of skin, combs, wattles, caruncles, and other 
fleshy or horny appendages. 
Of the feet. . . . Sole or greater development in male of spurs. 
Of the bill. . . . Male with more highly colored or larger bill than female. 
