What is "wyvernhail"

Wyvernhail is the fifth book in the Kiesha'ra Series by Amelia Atwater-Rhodes. The preceding four books in order are: Hawksong, Snakecharm, Falcondance, and Wolfcry. It is told from the point of view of Hai the gyrfalcon, cobra mix, who is struggling to find a way out of Ecl, or the darkness.

It was released on September 11, 2007.