Even though no information is officially announced, the video showing an Articuno in a gym battle is uploaded to YouTube (1:58 - 2:30). The Articuno fights against a Pinsir and a Flareon.
Articuno
Note:
The CP of the attacker is the number next to the names of Pokemon.
What the Articuno's fast move is not exactly sure, but it seems to Tackle. If it is Peck, it should be super effective, but the move is not in the video. Pisir's fast move looks Fury Cutter, and it is not very effective against the Articuno.
The Pinsir uses X-Scissor, a bug-type charge move, but it is not effective against the ice- and flying-type attacker.
The Articuno uses Twister, a dragon-type charge move and it defeats the first defender.
Articuno vs Flareon
The video ends when the battle between the Articuno and the Flareon starts unfortunately.