A female Sika Deer enters the woods from the marshland in Dorset. The sika deer can be active throughout the day, though in areas with heavy human disturbance they tend to be nocturnal. In Britain and Ireland several distinct feral populations now exist. Some of these are in isolated areas, for example on the island of Lundy, but others are contiguous with populations of the native Red Deer. Since the two species sometimes hybridise, there is a serious conservation concern.