Step 1: Obtain any falcosaur hatchling (but choice does have an impact later on)
Step 2: Complete the falcosaur's quest line. This questline involves leveling the pet to 25, doing pet battles, completing world quests, and killing dungeon and raid bosses (the raid boss is why the pet choice matters, as some of the targets are in Nighthold. For completing a quest line, you also get a mount.
Step 3: Go to Aviana in Highmountain. I approached her while mounted on the falcosaur mount and with the pet out, on a level 105. Talking to her, she has a new dialog option. Following this rewards the Ivory Talon.