A320 captain reported a bird strike after takeoff and returned to departure airport.

Attributes
ACN	1627841
Time
Date	201903
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZZ.Airport
State Reference	FO
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Large Transport
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Flight Plan	IFR
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 175 Flight Crew Type 2176
Events
Anomaly	Aircraft Equipment Problem Critical Inflight Event / Encounter Bird / Animal

Narrative:

During departure on xxl in ZZZZ had a loud bang right after rotation. We climbed to 4000 feet. All engines were still operating. We could smell a foul odor in cabin. Had a moderate vibration of unknown source. We suspected bird strike; but did not see any birds. I [requested priority handling]; notified dispatch and ATC of intent to return to field. Engine indications were normal; but the vibration indicated either engine or other structural damage. We also had an [landing gear control] fault. We proceeded to fly ILS to xxr in VMC conditions. Upon landing we stopped on the runway and had emergency personnel look for any indications of fire or smoke. None was noticed. Proceeded to taxi back to gate. Upon inspection of aircraft the number 1 engine received significant damage to multiple fan blades. Also ground proximity switches were damaged during impact. Airport officials recover remains of 9 ducks at departure end of runway. No injuries to any passengers or flight crew.

Original NASA ASRS Text

Title: A320 Captain reported a bird strike after takeoff and returned to departure airport.

Narrative: During departure on XXL in ZZZZ had a loud bang right after rotation. We climbed to 4000 feet. All engines were still operating. We could smell a foul odor in cabin. Had a moderate vibration of unknown source. We suspected bird strike; but did not see any birds. I [requested priority handling]; notified Dispatch and ATC of intent to return to field. Engine indications were normal; but the vibration indicated either engine or other structural damage. We also had an [landing gear control] fault. We proceeded to fly ILS to XXR in VMC conditions. Upon landing we stopped on the runway and had emergency personnel look for any indications of fire or smoke. None was noticed. Proceeded to taxi back to gate. Upon inspection of aircraft the number 1 engine received significant damage to multiple fan blades. Also ground proximity switches were damaged during impact. Airport officials recover remains of 9 ducks at departure end of runway. No injuries to any passengers or flight crew.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.