He became known as a member of the British Birds Rarities Committee who was responsible, with John Nelder and Max Nicholson, for publicly debunking the Hastings Rarities.
Ferguson-Lees spent his early years in Italy and France, but was educated in Bedford, England.
He turned down the chance to study zoology at Oxford University in order to get married, and became a teacher for seven years.
He was also a twitcher, once driving through the night to see a dusky thrush at Hartlepool.
[1] Ferguson-Lees was a member of the British Birds Rarities Committee from 1959 to 1963 and was responsible, with John Nelder and Nicholson, for debunking the Hastings Rarities - a series of rare birds, preserved by a taxidermist and provided with bogus histories.