The famous sculpture of 42 seagulls, which has hung in the entrance to Cardiff Airport since 1970, began life as a sketch of seagulls circling a rubbish heap.
But a recent refurbishment of the airport resulted in the aluminium birds being thrown into a rubbish skip.
Mr Nicholas, 62, is asking anyone who laid their hands on a bird to bring it back to him so he can reassemble his sculpture.
The pounds 4,000 commission for the sculpture in 1970 was the turning point in Mr Nicholas's career. "An international airport was a prize reference in a cv that was growing. I can no longer refer to it on my cv, except in a negative way," he said.
Mr Nicholas, a fellow of the Royal Society of British Sculptors, is pressing for a charter of artists' rights: "It shouldn't happen to anyone else." He is also demanding a full explanation from the airport authorities.Reuse content