A320 First Officer reported a bird strike shortly after takeoff. Geese were observed striking the aircraft and the number one engine resulting in heavy vibrations and severe damage to the engine. The crew returned to the departure airport.

Narrative

Normal takeoff out of ZZZ. And cleared left turn on course after T/O. I; the First Officer (FO) was the Pilot Flying and was still hand flying. A left turn was made and we continued our climb. As I leveled the turn I was cross referencing the instruments and visuals when I looked and saw a flock of geese 12 o'clock. I yelled out birds. The geese where unavoidable and we impacted within seconds of me calling them out. Damage to Engine #1 was apparent as the vibrations it was putting out where extremely high. And you could feel it throughout the airframe. The Captain selected the Fuel Control Unit (FCU) ALT of 4;000 feet and a decision to return to ZZZ was made as we didn't know the extend of airframe damage that had occurred. I started a decent and left turn for a downwind back to Runway XX. The Captain alerted the Flight Attendants of the situation and advised ATC. The Captain ran the overweight landing checklist. The secondary flight plan was then activated and the ILSXX was already programmed by me on the preflight so I set the airplane up for a base and intercepted the localizer coming back to ZZZ Runway XX. A visual approach was flown and a smooth landing was done for the overweight procedure. We then taxied to the gate and deplaned as normal and resumed normal ops. Upon deplaning we inspected engine #1 to find serious blade and engine damage.