20 
not appear to me to be quite decided ; and 
we need a greater number of observa- 
tions for that purpose than are yet within 
our reach. It is not, in fact, by a minute 
comparison of the dead carcases of birds, 
nor by a scrupulous indication of their co- 
lours, that we can hope to trace with a 
steady hand the line of demarcation which 
separates the species. Age, sex, season, all 
produce various changes in the covering of 
birds of prey; and diversities of plumage, in 
various situations, are common to them with 
many other species of birds." 
From the observations we have made upon 
different specimens, we have not the least 
doubt but that they are of the same species, 
differing only in the shades of their plumage. 
Willughby gives a curious account of 
the nest of this species, found in the wood- 
lands near the river Derwent, in the Peak of 
Derbyshire. He says it was made of large 
sticks, lined with two layers of rushes, be- 
tween which was one of heath ; that in it 
was one young and an addled egg, and by 
them a lamb, a hare, and three heath- 
poults. The young Eagle was black, hav- 
