Haigh et al (2012) Courtship behaviour of western hedgehogs in a rural landscape in Ireland
Title: Courtship behaviour of western hedgehogs (Erinaceus europaeus) in a rural landscape in Ireland and the first appearance of offspring, Lutra 55(1); 41-54. 2012
Authors: A.J. Haigh, F. Butler & R.M. O’Riordan
Background to study
An investigation into patterns of courtship behaviour including number of mates, duration of courtship, identity of pairings, juvenile emergence, timing of litters, number of offspring and their dispersal.
- Between June 2008 and June 2010, hedgehogs occupying an area of mixed agricultural land consisting of 23% arable, 64% pasture, 7% residential garden and small areas of scrub, marsh and wood were captured, marked and radio tracked to observes of courtship and juvenile activity in terms of season and habitat.
- All individuals were classified as adult or juvenile (<600 g and hind foot length < 3.6 cm), were marked using uniquely coloured heat shrink plastic tubes and injected with a Passive Integrated Transponder (PIT tag). The weights of marked individuals were measured weekly.
- Marked individuals were directly followed between June and September using spotlight surveys and the aid of a tip light placed on the hedgehog and the behaviour and location of each individual was obtained at 10 minute intervals throughout consecutive nights.
- Eight individuals captured from October were fitted with radio tags and when located, a ten minute focal survey of hedgehog behaviour was conducted before locating another individual.
- Courtship behaviour involving the circling of females by male hedgehogs and snorting was noted when observed and the length of time, individuals involved and whether this concluded in mating was recorded.
- Carcasses of road kill were obtained by the authors and as a result of public participation from across Ireland to aid in identifying litter sizes and incidences of breeding in relation to time of year.
- 24 hedgehogs were captured and both the adult and juvenile cohorts were male biased (3M:1F).
- Courtship involved males lunging towards females pushing her head underneath his body whilst she pushed him away and had a mean duration of 60 minutes (maximum 140 minutes).
- Of 14 hedgehogs monitored in 2008, courtship behaviour was observed twice. In 2009, 12 of 16 hedgehogs were observed in courtship (incl. 4 females engaged in courtship behaviour 33 times between April and July. In 2010, the sole tagged female engaged in courtship behaviour 4 times, all in May.
- Of the 39 observations of courtship behaviour, copulation was not witnessed between 16 individuals.
- Males were observed in courtship behaviour with up to three different females (mean 1.6 occasions per male) during the breeding season and were observed to be paired with the same female on up to six different occasions. In 2010 a single female occupied the study site and all four tagged males pursued her.
- 3% of courtship behaviour took place in pasture fields where the core range of females was located across all years during the breeding season and where multiple adult male ranges were concentrated.
- Mean annual ranges for males and females was 56 +67 ha and 16.5 + 0.49 ha.
- Juvenile emergence was recorded mid September in 2008 and in July during 2009 respectively. Juveniles remained close to their natal nests for the first week then extended their foraging trips, moving 0.24-0.64 km, but mostly settled within the same area suggesting juvenile dispersal is not common in hedgehogs.
- Four female carcasses obtained in June, July and September 2008 were pregnant when killed and in two the foetuses were well developed. The majority of road kill individuals were adults (N = 88) and 28 were juveniles which were most abundant in July.
Key messages to landowners and managers derived from these results
- Rehabilitated hedgehogs should be released into areas with diverse habitats, particularly females who may utilise different sites for courtship, rearing young and hibernation.
- The density of hedgehogs within pasture fields may peak between April and May when fertilisable females attract multiple males, thus land management activities during this time should be considerate of this.
- Surveying for hedgehogs needs to be conducted at least three times during their activity season and across different habitats to account for seasonal changes in their core areas of activity.