Dick Treleaven, whose home was in Launceston, became one of the foremost authorities on the peregrine falcon. Educated at Dulwich School, he went into the military, serving with distinction with the 14th Army in Burma. On his return, he visited an exhibition of paintings of birds of prey and became fascinated with the peregrine. He had always wanted to become an artist and soon made the acquaintance of a painter, George Lodge, who was to become his guide and mentor.

From the 1940s onwards, and for the next sixty years, he devoted himself to the observation and study of the peregrine on the north Cornwall coast. During the 1950s he found that the population was declining and, as a result of his investigations and analysis, it was found that pesticides were to blame. After a ban was imposed, the numbers began to improve until, much to his delight, a breeding pair were discovered again in Cornwall in 1969.

Treleaven's first book (1977) 'Peregrine - the Private Life of the Peregrine Falcon' was illustrated with his own drawings. In 1998 he published his second book, 'In Pursuit of the Peregrine' incorporating another 20 years of his experiences.

Dick was a founder member of the Society of Wildlife Artists, and exhibited every year in London. In 2007 he was awarded the MBE for services to ornithology.

In 2017 his paintings were included in an exhibition celebrating 'The Causley Century' at Terre Verte Gallery, Altarnun.