Parrott et al (2014) hedgehog geographically extensive survey
Title: A geographically extensive survey of hedgehogs (Erinaceus europaeus) in England, European Journal of Wildlife Research 60; 399-403. 2014
Authors: D. Parrott, T.R. Etherington & J. Dendy
Country: UK (west and south-west England)
Background to study
A geographically extensive and locally intensive survey of hedgehog density in pasture and amenity grassland habitat to investigate differences in habitat use and how these relate to regional densities of badger populations.
- Paired sampling of 125 amenity grassland and pasture fields using whole site spotlight searches for hedgehogs within 19.6km2 survey blocks in four counties of England (Cornwall, Devon, Gloucestershire, Herefordshire).
- Study sites were selected from aerial photography based on size (0.5-1ha) and if pairs of habitat were seperated by >500m but within 1500m and not seperated by major roads and rivers.
- All pairs of sites were surveyed for one night in early summer (26th June – 24th July) and replicated in late summer (31st July – 28th August) during 2006 which fell between associated spring and autumn badger surveys (Parrott et al, 2012).
- Spotlight searches commenced 1 hour after dusk and were completed before dawn and were carried out by two surveyors. Any hedgehogs encountered were collected, sexed, aged as adult (>500g) or juvnile and were held until the search was completed to avoid double counting the same individuals.
- Density of hedgehogs was calculated as the maximum number of encounters in any one survey night and was compared between habitat types and in relation to badger density estimates presented in Parrott et al (2012).
- Hedgehog occurrence was higher in amenity grassland (26% of surveyed sites) than pasture fields (2% of survey sites).
- Average weight of adults across all amenity grassland and regions was 861 + 31g and 855 + 32g in early summer and 853 + 49g and 576 + 45g in late summer for females and males respectively.
- In early summer, no adult males were encountered in pasture fields and females were only encountered in two of the four regions (Cornwall and Gloucs) weighing an average of 710 + In late summer, adults were only encountered in pasture fields in Gloucestershire weighing an average of 920 and 830g for males and females respectively.
- Hedgehog density was significantly higher in amenity grassland habitats (0.47 +09/ha-1) than in pasture fields (0.04 + 0.02/ha-1).
- At a regional scale, hedgehog densities across habitat types showed negative trends with spring and autumn badger densities.
Key messages to landowners and managers derived from these results
- Amenity grasslands are important habitats for hedgehogs and management strategies should aim to maintain and/or increase suitability of sites for hedgehogs.
- Badger density needs to be considered in surveys monitoring the distribution and abundance of hedgehogs.
- Pasture fields are less favourable habitat for hedgehogs and further research into factors influencing the use of pasture fields is required.