The Ryburgh Wildlife Group is very privileged and fortunate to have a short report by Joshua Rose. Joshua has studied the distribution of hedgehogs in the Ryburgh area for his dissertation.
He reports:
Over the period between June and September 2021, in collaboration with Norfolk Wildlife Trust and the Wensum Farm Cluster, I carried out hedgehog footprint surveys on seven kilometre square samples of core farmland in the Upper Wensum Valley, in addition to five surveys which had been carried out earlier in June by farmers themselves, using a method recently established in a national survey of hedgehog occupancy (Yarnell et al, 2014; Williams et al, 2018). All 12 surveys returned no detections of hedgehogs – this was immediately concerning.
However, over the same period, I had sent out a request to local parishes around the Upper Wensum area for details of any encounters with hedgehogs they may have had. Though the fact that all sightings were submitted from villages and other built-up areas could have been attributed to an innate detection bias, given that people will spend most of their time around built-up areas, recent gps tracking research by Pettett et al (2017A; 2017B) has quantified theories of a change in habitat selection in rural hedgehogs toward built-up areas.
Considering this, and prompted by the fact that Pettett et al’s research had taken place partly in the area, over April 2022 I carried out footprint tunnel surveys of Great Ryburgh and Colkirk, including public spaces and residential gardens. In addition, given that hedgehogs are known to disperse toward existing populations (Doncaster, Carlo and Paul, 2001), and that each village would be unlikely to support a sustainable population of hedgehogs (>120 individuals; Moorhouse, 2013) on their own, the farmland between Colkirk and Great Ryburgh was surveyed (excluding land surveyed during the 2021 farm surveys) with the understanding that a genetic corridor should, in theory, exist between both villages.
Both the surveys of Great Ryburgh and Colkirk returned detections of hedgehogs, in Ordnance Survey grid square references TF9527 (Great Ryburgh), TF9126 and TF9226 (Colkirk). However, none of the farmland surveys between the villages returned detections, indicating this corridor is unoccupied by hedgehogs. What this suggests overall is that the hedgehog populations in the Upper Wensum Valley are centred around villages, but that these populations, at least in the case of Great Ryburgh and Colkirk, are perhaps isolated – though further surveys of the land surrounding each village would be needed to confirm this.
I have made a series of recommendations in my thesis, primarily that there is a need for a more thorough survey of villages in the Upper Wensum Valley area and the land that connects them, in order to better understand the distribution of the local hedgehog population. Furthermore, I have suggested a targeted restoration of hedgehog population connectivity between villages using aggressive hedgerow planting and restoration, in a similar manner to a landscape connectivity project currently being undertaken in the Claylands.
However, what I cannot stress enough is that the local support for hedgehogs, as I have seen in many people’s gardens through feeding, landscaping and monitoring, is likely to be one of the most significant reasons that rural hedgehog populations haven’t been entirely extirpated. Though the feeding of wildlife in gardens can be contentious among conservation circles, the evidence suggests that in the case of the hedgehog it has been extremely beneficial. Therefore, through data protection rules with regard to my dissertation prevent me naming names, I would like to thank all of the villagers of Great Ryburgh and Colkirk for your work in helping conserve a vital part of the British landscape and an iconic species, and to encourage you to keep going – though the true extent of the hedgehog population and its decline is unknown, your efforts may very well turn out to be a crucial part of its survival.
Reference:
Doncaster, C.P., Carlo, R. and Paul CD, J., 2001. Field test for environmental correlates of dispersal in hedgehogs Erinaceus europaeus. Journal of Animal Ecology, 70(1), pp.33-46.
Moorhouse, T., 2013. Population Viability Analysis of Hedgehogs in Rural and Urban Habitats.
Pettett, C.E., Moorhouse, T.P., Johnson, P.J. and Macdonald, D.W., 2017. Factors affecting hedgehog (Erinaceus europaeus) attraction to rural villages in arable landscapes. European Journal of Wildlife Research, 63(3), pp.1-12.
Williams, B.M., Baker, P.J., Thomas, E., Wilson, G., Judge, J. and Yarnell, R.W., 2018. Reduced occupancy of hedgehogs (Erinaceus europaeus) in rural England and Wales: The influence of habitat and an asymmetric intra-guild predator. Scientific Reports, 8(1), pp.1-10.
Yarnell, R.W., Pacheco, M., Williams, B., Neumann, J.L., Rymer, D.J. and Baker, P.J., 2014. Using occupancy analysis to validate the use of footprint tunnels as a method for monitoring the hedgehog E rinaceus europaeus. Mammal Review, 44(3-4), pp.234-238.
Pettett, C.E., Johnson, P.J., Moorhouse, T.P., Hambly, C., Speakman, J.R. and Macdonald, D.W., 2017. Daily energy expenditure in the face of predation: hedgehog energetics in rural landscapes. Journal of Experimental Biology, 220(3), pp.460-468.