Badger Road Casualties

This analysis of Badger road casualties in our area was kindly supplied by Colin Howes (Yorkshire Naturalists’ Union) based on data supplied by Ian Massey (Scarborough Field Naturalists' Society). It covers the years 1967 to 2002 and provides a fascinating insight into the movements of our Badgers and why there are more casualties at certain times of the year.  Further records are always welcome, so please email details of any casualties to info@scarboroughwildlife.org.uk .

Badger Road Casualties in the Scarborough District: 
Trends in distribution, seasonal and annual frequencies.

Colin Howes Doncaster Museum & Art Gallery DN1 2AE
Ian Massey 4 Whin Bank Scarborough YO12 5LE

From 1967, badger road casualty data for the Scarborough region has been forwarded to the Yorkshire Naturalists’ Union by I.M. on behalf of the Scarborough Field Naturalists Society and by the late David Dunne on behalf of the Ryedale Badger Group. To date, some 128 records have been assembled from these sources.

Distribution and accident ‘black-spots’.
Distributional data of casualties, together with casual sightings and confidential information on sett localities, helps to interpret our understanding of the badger’s utilisation of the diverse landscapes and geology of the Scarborough region. Of the 10km squares within the region which have produced most casualty records the most significant are SE/98 with 10 (8%) casualties, SE/99 with 22 (18%) casualties and TA/08 with 29 (24%) casualties.

Three A (trunk) roads and two B roads are of particular significance in the Scarborough Region region, having accounted for relatively high numbers of badgers over the years. These are the A171 from Burniston to Cloughton Bank Top and on to the Falcon Inn and the Flask Inn; the A170 from Irton to West Ayton, Snainton, Allerston and Thornton-le-Dale; and the A64 from Seamer to West Heslerton. The B1262 from Jacob’s Mount to East Ayton, the B1249 from Staxton to Foxhole and the B1416 at Sneaton have also accounted for a number of casualties.

With respect to conservation and animal welfare, individual or multiple casualty records for single 1km squares could potentially help to identify specific ‘accident black-spots’ where highway mitigation features such as fencing, reflectors and even underpasses could be installed. In any event, for road safety purposes, the sites of recurring badger road traffic accidents need to be drawn to the attention of the police and highway engineers.

Seasonality
Figure 1, based on 126 records for which the dates were given, shows that casualties, signifying above ground activity, increase substantially in February and reach an annual peak in March. Neal (1986) associates this with high levels of territorial activity during this period when the litters are being born.

From May to August, numbers remain relatively low, despite this period including the busy holiday months when traffic flows would be expected to increase substantially. A late summer peak appears in September, which has been attributed to high levels of activity associated with preparations for the winter months. Of this period, Neal (1986) observes that ‘this is the time when feeding is of primary importance, territorial limits are less strictly observed and rather more animals are ‘living rough’ away from their main setts for variable periods’. The relatively low numbers of casualties in December and January illustrates this long period of winter inactivity with relatively few expeditions above ground.

Figure 2 is based on 34 casualties where the gender of the animals (16 boars and 18 sows) was recorded.

It demonstrates a marked separation of the above ground activities of males and females with the very high levels of boar casualties occurring in February and March. This has been associated with the high levels of territorial activity associated with the birth of litters and subsequent mating. Adult territory holding males being particularly active patrolling territorial boundaries at this time. Young males, reaching maturity and ejected from natal setts may be seeking out territories of their own. The high peak of casualties in sows in April and to a lesser extent in May, is associated with high levels of foraging in order to lactate and suckle the growing litters of cubs. The marked reduction in sow casualties after May coincides with the weaning of the cubs.

Annual frequency
The generally increasing frequency of road casualties as illustrated in Figure 3 is difficult to interpret though may be a function of a) increasing volumes of nocturnal traffic within the region, b) increasing numbers of badgers or indeed c) an increase in recorder effort.

Notable increases in particular years may be associated with prevailing weather conditions with drought years requiring badgers to forage further in search for soil invertebrates (eg. earthworms). The implication of extended foraging expeditions is that more roads are likely to be encountered and crossed more frequently. In the case of this study, the substantial increase in records from 1996 is largely due to the addition of records contributed by the Ryedale Badger Group, though in representing the input separately, it can still be seen that casualties are indeed increasing. 

References:
Neal, E. (1986) The Natural History of Badgers. Croom Helm, London.