Since your departure from the Evergrove, I've continued my studies of the Book of the Raven and I've discovered some information that will help you defeat the raven god.
Freeing the spirits has bound them to you, so I expect they will freely offer their assistance in the fight against the raven god.
When you first unleash the spirits, they will be dormant, as they have been for centuries. Using your heal-over-time spells, you can infuse them with energy, bringing them to life and gaining their aid in combat. When the magic fades, they will return to their slumber.
What follows is a collection of my notes on each bird spirit:
The Falcon Spirit
The spirit of the falcon is imbued with incredible speed and agility, highly regarded among the arakkoa for its keen hunting skills. It will lend you a measure of its speed in spellcasting and melee combat if you energize the spirit with a heal-over-time spell.
The Eagle Spirit
Arakkoa tradition holds that the eagle spirit was not as fast as its falcon brother, but possessed the greatest skill in the hunt. The eagle spirit will use its skills against your enemies if you use a heal-over-time spell to awaken it from its slumber..
The Hawk Spirit
The tablet speaks highly of the hawk, as though he might have once been in league with the raven. An ancient arakkoa symbol for vengeance, the hawk spirit was often invoked by victims of wrongdoing. Using a heal-over-time spell to awaken the spirit will allow you to share in its power, damaging those who do harm to you.