Saint Catherine's Hill Nature Reserve (SSSI) At 35 hectares the hill is the largest and most significant area of heathland in the Borough, providing habitat for rare reptile species such as the smooth snake and the sand lizard, as well as providing habitat for all of the UK's native reptile species. St Catherine's Hill is also inhabited by rare bird species, such as the Dartford Warbler, and butterfly species like the Silver Studded Blue.