Date: 201203
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: B737-300
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Flying; First Officer
Human factors: Workload; Training / Qualification; Time Pressure
Second reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical; Inflight Event / Encounter Bird / Animal
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Aircraft Aircraft Damaged; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Declared Emergency
Contributing factors: Environment - Non Weather Related; Aircraft
Primary problem: Environment - Non Weather Related

Narrative: We were operating flight scheduled service. The flight was late arriving and it was our last flight of the day during night conditions. We had 103 passengers onboard. After pushback we were cleared to taxi to Runway 15R; then cleared to takeoff Runway 15R. Normal takeoff until we saw at least two large waterfowl illuminated by the lighting from the landing lights. I was the pilot flying and reacted; but the closure rate was too fast to avoid a collision. The large waterfowl; most likely Canadian geese; struck the aircraft on the left side and we had a loud bang followed by increased engine vibration and changes in our engine parameters. We knew we took at least one in the #1 engine immediately. Also; we had a Master Caution light illuminate with an ENG indication. The Captain notified ATC and declared that we were coming back to land; needing assistance upon landing for an operational emergency. I continued as the pilot flying while the Captain assessed the situation and brought out the QRH to run the Inop checklist. During the bird strike; we had a high engine vibration of 4.0 units. Upon level off; I made sure that the engine parameters were still within limits and the all parameters were stabilized with the engine vibration under 3.0 units at 3;000 FT MSL and 210 KTS. The Captain notified the flight attendants; ATC; Company; and passengers of our situation and after our checklists were complete; we told ATC we were ready for an approach to Runway 10. The Captain asked if I was still comfortable with the landing and I said; yes I was. We again notified Tower that we wanted the fire trucks to check out the aircraft and brakes upon landing. We landed flaps 30 with the #1 engine pulled back slightly and taxied off the runway into the deice pad so the fire trucks could check the condition of the aircraft. After a small cool down; the Captain shut down the number one engine and coordinated with the rescue team. They communicated that the number one engine had significant damage and that the brakes were approximately 120 degrees. We landed 1;000 LBS below maximum landing weight and there were no brake limit cooling from the performance calculations. I communicated with Operations; flight attendants; and passengers about our event and our instructions. We were cleared from the fire rescue team and taxied back to the gate. I think our entire crew handled this event with good CRM and teamwork. TRACON handled our situation great and it was nice to have good controllers handling us. Our flight attendants kept the passengers calm under a possible stressful event. Our fire rescue team was in excellent position for us to taxi off the runway and for them to assess our aircraft. My Captain handled this event calmly; under control; and with professionalism. I think under non-normal events it is great to have good communications and CRM amongst all the members to conduct the flight safely.


Second narrative: [Narative #2 had no additional information.]


Synopsis: At least one Goose entered a B737-300's left engine at 1;800 FT after takeoff causing a high engine vibration reading and the ENG light so the crew declared an emergency; completed the QRH and returned to the departure airport.