Jamieson, Fausset and Brown on Isaiah 46:11

11. ravenous bird--Cyrus so called on account of the rapidity of his marches from the distant regions of Persia to pounce on his prey (see on Is 41:2; Is 41:25; Jr 49:22; Eze 17:3). The standard of Cyrus, too, was a golden eagle on a spear (see the heathen historian, Xenophon, 7, where almost the same word is used, aetos, as here, ayit).

executeth my counsel--(Is 44:28; 45:13). Babylon represents, mystically, the apostate faction: the destruction of its idols symbolizes the future general extirpation of all idolatry and unbelief.

purposed ... also do it--(Is 43:13).