Given what you've learned about the biological species concept, should g. fortis and g. scandens continue to be considered separate species?

Yes

Explanation:

Both these g. fortis and g. scandens are two different species of medium sized finches.

Though these two have evolved from the same species but they have diversified tremendously through the process of allotropic speciation.

Though most of their physical characteristics i.e body shape & size, beak size has not changed in due course of time but the singing pattern of these two species became different from each other and through this characteristics they have maintained differences among themselves.

Therefore, g. fortis and g. scandens continue to be considered separate species