Looking for novel about winged humanoids who donate blood in exchange for human carrion.

[AztecWill]

Sadly can't remember the title or author of a book I read in the early 1980s: The book described a world where there were humans living and human like figures with wings. The human government, in secret, had agreed a pact with the bird figures. In exchange for allowing them to feast on the bodies of deceased humans the bird figures would donate blood which extended the lives of the human's leaders - I think the governing body was called the Chancery. The only other detail I can remember is that the world had a circular sea than ran all the way around the planet dividing it into two. Ships would endlessly circle the globe on this sea.

 

[Suzecog]

This sounds like The Awakeners by Sheri S Tepper.