Mary Bonham-Christie (23 July 1865 – 28 April 1961) called "the Demon of Brownsea", was the reclusive owner of Brownsea Island in Poole Harbour, Dorset from 1927 until 1961.
Mary Florence Whitburn was born in 1865, the daughter of Charles Joseph Sofer Whitburn and Fanny Hales Whitburn, of Addington Park in Kent. She married Robert Bonham Bax Christie in 1889; they had a daughter, Elsie, and sons John and Robert.
Mary Bonham-Christie purchased Brownsea Island at auction in 1927, for £125,000. She ordered the island's 200 residents to leave, and banned hunting and fishing on grounds of animal cruelty. The protracted legal battle that followed may have turned violent with the fire that consumed much of the island in 1934 (the cause of the fire was never determined, though Bonham-Christie blamed the Boy Scouts and forbade them to camp on the island afterwards). Fearing further threats, she hired a bodyguard to eject intruders to the island. While unpopular, her minimal interference with the island's natural contents meant that it became a flourishing habitat for red squirrels,Sandwich tern, avocet, and other wildlife. "The old lady knew she wasn't popular but I don't think she cared," said a former boatman who served the island during her tenure there.
Mary Bonham-Christie died in 1961, aged 96 years, on the day that her family had arranged for her to be moved to a nursing home off the island. Her grandson and heir John Bonham-Christie had plans to develop the island. A group of environmental conservationists, led by Helen Brotherton, organized to oppose his plans. They succeeded in raising sufficient funds to persuade the National Trust to take over the island, while allowing the Bonham Christie family to avoid death duties on the property.
There is a monument to Mary Bonham-Christie in the churchyard at Marston Bigot; her remains were cremated at Bournemouth, and interred at Brownsea Island. In 2007, BBC Radio 4 broadcast a half-hour report about Mary Bonham-Christie, titled "For Nature, Not Humans."