James McKenzie spat out a piece of his tongue onto the street after Bethaney Ryan, 27, had ripped it off with her teeth during an incident in Edinburgh.
The gull then flew down and grabbed the muscle, making off before the injured man could retrieve it.
Edinburgh Sheriff Court was told about the grisly incident - which left the victim maimed for life - when Ryan appeared in the dock to plead guilty to the attack last Thursday.
Prosecutor Susan Dickson said the pair clashed as they passed each other on Leith Walk at around 8pm on August 1, 2019.
Ms Dickson said the pair were strangers but “an argument developed” between them.
The court heard Ryan had tried to walk away from the confrontation.
The fiscal said McKenzie continued to be aggressive towards Ryan and he approached her again with “a clenched fist”.
Ms Dickson said: “Miss Ryan, somewhat oddly, responded to that by pushing him on the body and kissing him.
“She kissed him on the lips and during the course of that she bit through his tongue which caused a piece of his tongue to be removed.
“Mr McKenzie walked off and spat a part of his tongue out at which point the piece of muscle was picked up by a large seagull that made off with the piece of tongue.”
The fiscal told the court the chunk of tongue bitten off was approximately two centimetres by three centimetres in size.
Ryan was later arrested by police and McKenzie attended hospital for treatment where “the laceration to his tongue” was said to be “oozing blood”.
The fiscal added: “He did not require surgery given the piece of tongue was no longer available and could not be reattached.”
Solicitor Neil Martin, defending, said the attack by his client, of Lochend, Edinburgh, was “a very strange incident in the round” but added he would reserve his full mitigation to the sentencing hearing.
Sheriff Nigel Ross said “because of the serious nature of the incident” he needed to defer sentence for the preparation of reports to later this year.
Ryan pleaded guilty to assaulting James McKenzie by pushing him on the body, kissing him and biting off part of his tongue to his severe injury and permanent disfigurement at Leith Walk, Edinburgh, on August 1, 2019.