When an area has no or limited coyotes and lots of fox, raccoon and skunks coyotes do hold them down and nesting season survival rate is better. That is not the case in all areas or all types of birds. Coyotes are hell on turkeys year around. I live next to a wild life area. 12 years ago lots of deer, turkey raccoon, pheasant, rabbits and fox but not coyotes. 12 years later lots and lots of coyotes. Limited deer and raccoon. Pheasants are rare and the turkeys and rabbits are gone.
I still read studies that claim coyotes don't kill health adult deer and antelope. Since I have seen both taken repeatedly by coyotes so I know that part is 100% BS.