DENVER (KDVR) A United Airlines flight was forced to make an emergency landing at Denver International Airport on Sunday after what appears to be a rare wildlife strike potentially involving a rabbit.

While wildlife strikes are relatively common at U.S. airports, more than 20,000 were reported last year, according to Federal Aviation Administration data, only four involved rabbits. One of those incidents occurred at DIA.

Air traffic control recordings obtained by FOX31 captured the moment pilots reported engine issues shortly after takeoff.

“Every once in a while, a little burst of flames coming out the right engine,” one air traffic controller can be heard saying.

“Yeah, affirm, we think we lost our right motor,” the pilot responded.

Roughly 75 minutes after departure, the flight returned safely to Denver. Additional tower audio referenced a “dead rabbit just right of the centerline” and “lots of rabbits” on the taxiway.

FOX31 shared the recordings with aviation safety expert and longtime pilot Steve Cowell, who said the circumstances are highly unusual.

“What an incredibly rare circumstance. You’re dealing with an airport that has 695,000 operations a year, and we have one rabbit strike,” Cowell said.

DIA spans 55 square miles much of it formerly farmland making it prime habitat for rabbits and other wildlife. Cowell said the airport works closely with the USDA to maintain and adapt a wildlife mitigation program designed to prevent incidents like this.

“You develop a program, and then when you see something like this happen, you modify it to make everything just that much safer,” Cowell explained.

“They even have things where they will shoot frozen turkeys into a running engine, to make sure the engine isn’t going to have a catastrophic failure.”

Airport officials have not yet confirmed what type of animal caused the engine issue, but confirmed they are reviewing the incident. More information about Denver International’s wildlife program can be found at flydenver.com.