If you’re wondering how to get HS card Avian Watcher – you have to complete the third boss called Terestian Illhoof in the third wing of the One Night in Karazhan adventure The Menagerie.
Terestian Illhoof is a push over. He has immunity and keeps populating 1/1 minions that do 2 damage to him when they are killed. A few spells like arcane missiles and arcane explosion makes quick work of this on normal mode.
Hearthstone Card Avian Watcher
The card reads Battlecry: If you control a Secret, gain +1/+1 and Taunt.
As a 5 mana 3/6 that will be a 4/7 if you have a secret this is pretty decent for a neutral minion.
Probably going to see this card in Reno lists, control decks for classes that run secrets, and will be good in the arena if you can activate it.