William Homan Thorpe FRS (1 April 1902 – 7 April 1986) was Professor of Animal Ethology at the University of Cambridge, and a significant British zoologist, ethologist and ornithologist. Together with Nikolaas Tinbergen, Patrick Bateson and Robert Hinde, Thorpe contributed to the growth and acceptance of behavioural biology in Great Britain.
William Homan Thorpe was born and died on the same April day 84 years later.
William Homan Thorpe was born on April 1 and died on April 7 84 years later, not the same day. Without using the numerals for the date, the system probably tripped on what the statement meant.