Resilient Sinew

Source
This item drops from:
 * Marauding Owlbeast in The Hinterlands
 * Frayfeather Hippogryph in Feralas
 * Frayfeather Skystormer in Feralas
 * Frayfeather Patriarch in Feralas
 * Antilus the Soarer in Feralas
 * Frayfeather Stagwing in Feralas
 * Vicious Owlbeast in The Hinterlands
 * Savage Owlbeast in The Hinterlands
 * Primitive Owlbeast in The Hinterlands

As a quest objective
This item is an objective of Natural Materials.