Burch (1995) hedgehog spool & line habitat use
Title: The use of spool-and-line tracking to determine habitat use in land vertebrates: the European hedgehog (Erinaceus europaeus) as a case study, MSc thesis, Manchester Metropolitan University 1995
Authors: K Burch
Country: UK
Background to study
Investigation into habitat use of a mixed rural area in north-west England using spool-and-line method to;
- a) determine habitat preferences and movement patterns in hedgehogs at a microgeographic scale, and b) to assess the value of spooling as a method for determining habitat use against direct observation and radiotracking.
Method
- Six rehabilitated hedgehogs, including three males and three females were released using soft-release methods and staggered entry into successional grassland habitat in May and June 1995.
- Each individual was fitted with a radio transmitter to enable recapture and ~280 m of white 2-ply nylon which was fitted within a spool case attached to the lower back. Spools were replenished nightly, <2 hours after individuals emerged from their nest, which was located during daylight hours using radio-telemetry.
- Each night, the thread was tied off and the animal left to roam. Animals and spool lines (n=44) were relocated early each morning and habitat selection and use for a partial hedgehog night was recorded by following and measuring the spool line.
- The monitoring area comprised of a 600 metre radius from the release site and included deciduous woodland, regularly mown monoculture grass (golf course), gardens, arable fields, an ornamental tree plantation and neglected orchard. The area was occupied by European badgers Meles meles.
- The proportion of spool line present per habitat, habitat avoidance and total range area was used to assess habitat use and calibration of spool-and-line trajectory in different habitat types was carried out and errors incorporated into the analysis using a correction factor.
Key results
- Hedgehogs showed the strongest preference for garden habitat and also selected for deciduous woodland and monoculture grassland but avoided arable land. Successional grassland was midly avoided and orchard and pasture areas were not used at all.
- Within deciduous woodland habitat a strong preference for areas of leaf and other litter in mud (ditch channels for instance) and a negative preference for mixed understorey was observed.
- Within garden habitat, a preference for microhabitats that included leaf litter, bare earth and compost heaps was observed.
- Hedgehogs selected for edge habitat when ranging within monoculture grassland.
- In all instances, habitat use and ranging incorporated an average of 237 m per night and is thus under-representative of hedgehog ranging patterns and habitat selection.
Key messages to landowners and managers derived from these results
- Gardens provide a suitable habitat for hedgehogs due to the availability of favoured microhabitats such as leaf litter, compost heaps, grassland and bare ground that is accessible within a small distance.
- Facilitating access to garden habitat for hedgehogs should be encouraged and include creating holes in fences and bounding gardens with more permeable features, such as hedgerows.
- Gardens with a variety of habitats including leaf and grass piles, compost heaps, flower beds and vegetable patches are suitable for hedgehogs.
- Arable fields may prevent a barrier to hedgehog movement; leaving grassy margins and hedgerows around the edges of fields may increase movement and suitability of arable areas for hedgehogs.
- Golf courses, particularly with areas of deciduous trees, can provide suitable habitat for hedgehogs and thus should be included in survey efforts and considered in management plans.
- Landscapes with a variety of habitats including deciduous woodlands, mown grasslands and gardens at a small spatial scale are likely to be most suitable for hedgehogs.