The Sorceresses of Lazaronia — Laraine Anne Barker

Esmé ‘s heart plunged again as twelve pairs of fierce black eyes turned in her direction. Then it leapt like a startled rabbit. For without warning most of the creatures took off at speed, screeching like thwarted vampires, while their chief commanded their return in vain. Good, she thought. Now there were only two to deal with. Next moment her heart seemed to stop dead: the creature perched on Mark's midriff folded its wings. It moved over. The one on the ground leapt closer.
Then, as one, two cruel, open beaks jerked downwards.

Mark has been kidnapped by Mirabell and Fallanein and left in the Lazaronian desert to die. Esmé is trying to rescue him.
But she is nearly half a world away. And there are two huge vulcarrions known as the Angels of Death already perched on the fallen young man 's apparently unconscious body …