A scifi book about humans fighting aliens trying to wipe out all intelligent life.

I remember reading a book series a long time ago that I enjoyed but can't remember much about it other than the title. The main protagonist was a Male, who was on a ship that I think traveled into the future where aliens are wiping out all intelligent life. I remember there were also some soldiers that they called doughboys I think. And there was a random line about how all the crows were also gone because they were more intelligent than average animal. I also vaguely remember they got to like a alien space station type thing where they had a device that let you communicate to other species.

Edit: I think it had "war" in the title but I could be wrong.