What benefit does autumn olive have? Yea birds eat the seed, but they just spread it all over. Autumn Olive takes over in some areas and competes with our more desirable native understory trees and shrubs...There are whole mountain sides here that have an understory of pretty much autumn olive only. Deer do not browse autumn olive.
The bush honeysuckle is bad news as well, deer will browse it, but I cut them out ASAP.
American Plum, Black Haw, crabapple, spicebush, Dogwoods, azalea, sumacs, etc. are some good native understory species to have around or to plant.