Hogwatch recently received an article by Yorkshire naturalist Colin Hines about the diet of hedgehogs during the prolonged period of drought in 1976.
Readers of a certain vintage will recall that the drought lasted the whole summer with very high temperatures recorded day after day, It is probably the period when a popular newspaper first coined the phrase “phew what a scorcher”.
Hedgehogs are carnivores and have a very mixed diet mainly consisting of earthworms, slugs and snails, beetles and other insects, insect larvae, birds eggs and carrion.
Periods of drought have a pronounced effect on earthworms. They retreat deep into the soil and become inactive by curling up in a chamber – known as aestivation.
Thus a staple of the hedgehog diet would not be as available as in a more typical UK summer.
Colin Hines studied the diet of hedgehogs by examining their droppings found in his garden in Sprotborough, near Doncaster, during the 1976 drought and after it ended in September.
He found that during the drought the most frequently recoded prey items were earwigs and then ants. As soon as it started to rain the most recorded prey item became earthworms emerging from their period of enforced inactivity.
Thus hedgehogs in the Doncaster study were able to adapt to extreme weather conditions for a period of three months.
Whether they could remain healthy on a diet of insects for longer periods is not known. Recent research by the Organic Research Centre looking at the wild food available to free range pigs analysed the crude protein contents of different prey items they could consume when foraging.
The percentage protein in the dry matter in earthworms was 51.66% and for slugs 62.59% more than insects and their larvae. The two groups were also richer in essential amino acids than insects.
Hedgehogs have to put on a lot down significant fats reserves in autumn so they survive hibernation and the quality of their diet may be an important factor in them reaching the critical weight of at least 450g (1 pound).
Colin Hines’ research has provided a valuable picture of how hedgehogs can adapt to survive drought. It is believed that hedgehog populations are very low in intensively farmers areas where , for instance, insecticide usage may be high and suitable habitat sparse. Thus in drought years, it could be that arable hedgehogs struggle to find sufficient food to substitute for earthworms (and slugs). Suitable habitat may also be lacking.
The importance of gardens with suitable habitats for sleeping, foraging and hibernating hedgehogs cannot be overestimated. Such habitats need to be linked to allow hedgehogs to roam freely in search of food and mates. That means leaving gaps in fencing as well as suitable habitats and sources of drinking water.
We also need to know far more about how changing climate could be impacting on hedgehog’s diets and behaviour.