The Making of Species 
yellow as in the normal type, and the plumage of 
the back of the wings is longitudinally streaked 
with white instead of barred. Several examples 
of this form were found, along with normal young, 
in the nest of one particular pair of little owls in 
Italy, but the whole family were foolishly ex- 
terminated by local ornithologists. 
The reed bunting (Eméberiza schoentclus) exists 
in two distinct forms—one having a much stouter 
bill than the other (Z. Ayrrhulocdes). This prob- 
ably is an example of a mutation. 
The rare yellow-rumped Finch (Munza flavt- 
prymna), of Australia, has displayed a tendency 
to change into the allied and far commoner 
chestnut - breasted Finch (JZ. castanezthorax) 
during the lifetime of the individual (Avicultural 
Magazine, 907). Conversely, the male of the 
common Red-billed Weaver (Quelea quelea) of 
Africa has been found in its old age to assume 
the characters of the comparatively rare Q. russz, 
its black throat becoming pale buff as in that 
form. 
Everyone is familiar with the chequered 
variety of the common blue-rock pigeon, in 
which the wings are regularly mottled with 
black instead of being barred. This form some- 
times occurs among wild birds, so that it has 
been described as a distinct species. It is 
important to note that there are red, dun, and 
silver chequers as well as blue ones. 
98 
