Haigh et al (2014) Hedgehog mortality on Irish Roads
Title: Hedgehog Erinaceus europaeus mortality on Irish roads, Wildlife Biology 20: 155-160. 2014
Authors: A.J. Haigh, R.M. O’Riordan & F. Butler
Background to study
Hedgehogs are one of the most common mammalian road fatalities in Europe and this study investigates the extent of road casualties in Ireland in comparison to other areas, the seasonal and sexual variation in road fatalities, whether road kill sites can help to identify habitat preferences and if hedgehog deaths are randomly located or whether accident hot spots can be identified.
- Seasonal patterns in road fatalities were investigated by intensively surveying two roads which consisted of motorway, dual carriage way and single lane traffic (sum distance of 259.5 km) for hedgehog road kill.
- Surveys were conducted by vehicle in the mornings and at regular intervals for 11 months of the year between April 2008 and November 2010 (excluding December). The location of hedgehog road kill was recorded using a handheld GPS device.
- The habitat type on either side of the road of the casualty location was recorded and scored in accordance with that of Morris and Morris (1988). The proportion of each habitat along both routes was quantified using aerial photography.
- A K-function analysis using Arc Geographical Information System was used to evaluate whether road casualties were spatially clustered or randomly located.
- Patterns between male and female and juvenile (<600 g, hind foot length <3.6 cm and jaw length <4.5 cm) and adult hedgehogs were assessed using carcasses collected across Ireland by the author and by members of the public between 2008 and 2010.
- Over three years, 133 hedgehog fatalities were observed, which totalled 0.264 casualties per 100 km of road or 1 casualty per 379 km of road.
- There was significant variation in the habitat where casualties were located with the majority of hedgehog carcasses found on roads that bordered pasture which was also the most dominant habitat type, suggesting that hedgehogs utilised this habitat in accordance with its availability.
- There was a greater number of hedgehog casualties near arable land than expected based on the extent of this habitat within the surveyed area.
- 17% of carcasses were located beside residential areas.
- K-function analysis indicated that the distribution of hedgehog road mortality was more clustered than would be expected from chance within a 259.5 km section of road. Thirteen clusters were identified along the route with up to six carcasses located at the same spot over the three year period. Nine of these clusters (69%) were located close to towns and junctions.
- Of the 134 carcasses that were assigned a sex, significantly more males (N = 67) were collected as road kill than females (N = 37).
- Female road kill peaked in June, July and August with female deaths higher than males in August only.
Key messages to landowners and managers derived from these results
- The spatial analysis of hedgehog fatalities on roads is a useful method for deriving potential hot spots for casualties that can help to inform on:
- suitable locations for road crossing structures for hedgehogs,
- factors that influence road crossings so that suitable mitigation measures can be enforced in light of new roads and development
- suitable locations to locate wildlife crossing signs, if deemed suitable, to inform drivers to be aware and alert of hedgehogs crossing the road.