Rautio et al (2013) The effects of sex and season on home range in European hedgehogs
Title: The effects of sex and season on home range in European hedgehogs at the northern edge of the species range, Annales Zoologici Fennici. Vol. 50. Finnish Zoological and Botanical Publishing. 2013
Authors: A. Rautio, A. Valtonen & M. Kunnasranta
Background to study
An examination of the spatial ecology of hedgehogs and how this varies between sexes and across seasons.
- 25 adult hedgehogs (males n = 13, females = 12) were captured and fitted with radio transmitters.
- For each individual, body weight measurements were taken every two weeks and their area of home range was calculated from radio tracking fixes that were obtained every two hours, nightly for between 4 days and >1 year, primarily during the active season (April – October).
- Seasonal home ranges and core areas were calculated using Minimum Convex Polygons of location data (minimum of 30 fixes/individual) and included the mating season (1 May – 15 June), post-mating season (16 June – 31 July) and pre-hibernation season (1 August – 15 September).
- Home range sizes, percent overlaps and body weight changes were investigated across seasons and sexes.
- The mean number of fixes obtained per night per individual was 4.3, the mean tracking period per animal was 50 nights and the number of fixes did not correlate with home range area.
- Male home range sizes (81.6 +2 ha) were nearly twice the size of females (30.3 + 7 ha) resulting in sex being a significant factor influencing home range size.
- Both home range and core areas were significantly influenced by season and this varied between sexes with males occupying a larger home range and core areas during the mating seasons, after which the area of use declined being smallest pre-hibernation. Females however had the smallest home range and core area during breeding and this increased until pre-hibernation when they occupied the largest area relative to other seasons and to males.
- Body weight did not significantly influence the size of home ranges or core areas for males or females.
- None of the core areas used by females overlapped post-mating and pre-hibernation, but ~40% of the females core area overlapped with another female during the mating season.
- A significantly higher proportion of female to female home range overlap was observed during mating season than pre-hibernation when few female home ranges overlapped.
- For all seasons, individuals’ core areas that overlapped, did so with the opposite sex more frequently than with individuals of the same sex.
- The percent overlap in home ranges of males was dependent on the sex of the neighbour as the percent overlap with other males was larger than with females.
- Differences between the percent overlap between core areas and home ranges across seasons suggest that locations and centres of home range shift during the active season, this was particularly evident in males whose home range centres shifted more so than females who remained in similar areas.
- The mean body weight of males was 858 + 17g was significantly heavier than females 757 + 12 g and significant differences between seasons were observed with both sexes being lightest during mating season and heaviest pre-hibernation.
- Average weight loss during hibernation (Aug/Sept until April/May) was 28%.
Key messages to landowners and managers derived from these results
- Hedgehogs in Finland, where the growing season is shorter (~5 months), acquire enough resources by exhibiting larger home ranges rather than shifting their diet, thus it is important to mitigate against reductions in food availability resulting from land use change and/or management to reduce the need to hedgehogs to range further which increases risk of predation or death.
- When releasing rehabilitated hedgehogs into the wild, particularly females at the beginning of the breeding season, it is important to consider the impact on resident females who may be intolerant to additional females during this time.
- When conducting surveys to determine hedgehog presence, it is important to carryout surveys at least 3 times during the activity season as their ranges drift during seasons increasing the risk of a false negative.