Griffins.
So I think someone should write a paper on sexual dimorphism in griffins. Were there evolutionary pressures that caused males to replace their wings with spikes? Are the spikes used in courtship displays? I find it interesting that the sexes would diverge to the degree that they fill different ecological niches. The only species I can think of where flight capability varies between the sexes are some insects. Also, are griffins apex predators, or are they preyed upon by things such as dragons?