 Formerly, the Spanish imperial eagle was considered to be a subspecies of the eastern imperial eagle, but is now widely recognised as a separate species due to differences in morphology, ecology, and molecular characteristics.This is a large raptor and fairly large eagle, broadly similar in size to its cousin, the eastern imperial eagle, which is found in a considerably different distributional range.Compared to sympatric largish booted eagles, it is somewhat smaller than the golden eagle and somewhat larger than the Bonelli's eagle.