Badger Biology and Ecology
One of Britain's six indigenous members of the Mustelidae family, badgers are a medium- sized, powerfully-built omnivore with a distinctive white head and black stripes through the eyes. The dorsal and lateral body shows an overall grey colour, derived from the white base and tip, with a broad black band on the long guard hairs, which overlays a finer shorter pale under-fur. A less common but widespread colour variation is the erythristic or ginger coat, with the normal black band giving way to a gingery colour caused by two recessive genes instead of the normal combination of dominant and recessive genes. The average head and body length is 75cm for males and 72cm for females with both sexes having 15cm tails. Droppings vary from loose to firm and are similar to dog, with a characteristic sweet, musky smell when anointed with musk, but rather chemically scented otherwise. They are usually deposited in uncovered shallow pits. Where these are grouped together they are known as latrines and often indicate a territorial boundary, especially at the main mating times. Eye sight is poor but sense of smell is acute. Foot prints show characteristic broad central pads with five toes forward facing; large front claws impress deeply in soft substrata where often you can see a double register with hind foot over front. Walking tracks show padding just either side of median line.
Badgers are opportunistic omnivores with a complex breeding cycle. The phenomenon of delayed implantation enables them to mate in any month albeit usually in spring, with a later mating in autumn, and yet they produce their young in early spring the following year. Cubs are generally born in February or March and may remain within the group. Living in family groups known as clans, they are generally nocturnal. Their setts are underground tunnels and chambers dug in suitably well-drained substrata or cavities in rock cairns. Kruuk (1989) found territory sizes from 100 to 300ha in Speyside, and between 150 to 200ha in a West coast location. Earthworms are a nationally favoured food source and in Central Eastern areas, where grass pasture dominates, Lumbricus terrestris is taken in large quantities. For badgers further north and west, a diet of the much smaller Lumbricus rubellus generally means lighter body weight. In addition, other invertebrates are important, together with rabbits and smaller mammals in certain areas. Sheep and deer carrion can be vital in hard winters especially in remote areas, with frogs and fruit adding a seasonal variation.
Badgers in Scotland
The Scottish Badgers national survey, 2006 - 2009 found the highest density of main setts occurred in areas where the dominant habitat was arable farmland, deciduous woodland or intensive grassland. Setts were also present in other habitats including coniferous woodland, urban, wet moorland with drier moraines, high-altitude rocky terrain and coastal areas. The regions containing the highest estimated densities of main setts were Borders and Lothians. Tayside, Central and Highland contained the lowest estimated densities. Geology reflects the type of setts to be found, with light soils allowing extensive digging in Eastern, Central and Lowlands, whilst rock cairns in Highland region may have no signs of excavation.