This is a Cultural legacy IMO of the Original Barbarian rulers of the Old World. These are modern day Kyrgyz of Central Asia roaming the Steppes on Horseback hunting wolves with Golden Eagles.
They train these Egles to kill marmots, then small foxes, then full grown foxes, then wolf cubs and finally full grown wolves.
If that isn't a barbaric passtime what is? Its like the height of barbarism and refined skill. I mean what is more bad ass than that? Invading and conquering China, India and Europe I guess.From the Wikipedia Entry on Kyrgyz:
V.V. Bartold cites Chinese and Muslim sources of the 7th–12th centuries AD that describe the Kyrgyz as having red, sometimes blond hair, blue or green eyes, and white skin. These features were markedly different from those of modern Kyrgyz, which led Ibn al-Muqaffa to suggest in the 8th century AD that the Kyrgyz were related to the Slavs.
The descent of the Kyrgyz from the autochthonous Siberian population is confirmed by recent genetic studies. Remarkably, 63% of modern Kyrgyz men share Haplogroup R1a1 (Y-DNA) with Tajiks (64%), Ukrainians (54%), Poles and Hungarians (~60%), and even Icelanders (25%). Haplogroup R1a1 (Y-DNA) is often believed to be a marker of the Proto-Indo-European language  speakers.
Because of the processes of migration, conquest, intermarriage, and assimilation, many of the Kyrgyz peoples that now inhabit Central and Southwest Asia are of mixed origins, often stemming from fragments of many different tribes, though they speak closely related languages.
Before they became Muslim they proacticed Shamanism. I can see the Eagle playing a role similar to a powerful Totem, which as these Barbarians conquered people to the South East and West later became a symbol of the Imperium.