Found: Poul Anderson SyFy: Human captain and alien bird-like co-pilot

I'm almost certain it was a Poul Anderson book, (he penned over a thousand!), that I read probably during 1960 to 1970. It was science fiction about a human captain and his co-pilot who was a large bird-like alien. I believe they were searching for who wiped out the human race. And, after a very long time, we found out it was the same race of bird-like aliens who was the co-pilot of the human.

Maybe The Last Legionary series by Douglas Hill?

It's After Doomsday by Poul Anderson

Thanks for thinking about it Nerika. Pretty sure it is "After Doomsday." Thanks again for trying.

>3 dukedom_enough: . . . Yes! Wow! Thanks so much dukedom_enough. I really appreciate it. Thanks.

>5 AZBob1951: you're welcome