July 11, 2014

Hedgehog...not in my garden!

Anton Lategan (EcoTraining's Director) undertook a marketing trip to the UK early in June. He was hosted by James at his home in the UK and James shared this interesting story with us...

"I think you’ll be pleasantly surprised when you learn that it is all happening right under your nose! I was.

As she emerged for her nightly insectivorous forage the rustle of leaves gave her well concealed location away. As I strode over in the direction of the noise, the rustling continued. Then as she detected my proximity there was silence as her survival instincts kicked in. But I had no trouble finding her in the undergrowth. Until a year ago when I moved to England, I regularly joked that hedgehogs didn’t exist. Having never seen one what proof did I really have that the do exist? However, this evening I had found all the proof I needed (with witnesses) and after curiously examining the ball of spines she was left to carry on with her slug-hunting in peace. I had found a European hedgehog (Erinaceus europaeus) in my back garden.

Bath is an ancient Roman city in the south west of England very close to Bristol. While it is located in an area of outstanding natural beauty, it is hardly the expected setting for a dramatic wildlife encounter to unfold. So when about 10 days later, on 1 June, I discovered a curious pile of leaves, I was surprised to learn that it was in fact a hedgehog nest.

While the IUCN has categorised the European hedgehog as Least Concern as a species, it has, since 1997, been identified as a species in the UK that requires conservation and greater protection. It has also been identified as a priority species in the UK since 2007 because of an identified decline in numbers with an estimated 25% loss of the population in 10 years. So not only did I have a nesting hedgehog in the garden but a protected mammal species breeding in the garden.

Weeks went by and occasional sightings of the sow were complimented by regular evidence of nesting activity in the mound of Beech (Fagus sylvatica) leaves and plastic bags. Without disturbing the nest it was not possible to determine the exact breeding state. It is common for hedgehog sows to kill their young if she senses a threat to them, or to herself, within the first few days after birth and she will in fact cannibalise them too. During the last week of June, the sow was active earlier in the evenings and we started to observe her while it was still light. This change away from normal behaviour was perhaps the first significant indicators of her state. June and July tend to be the height of the breeding season with most litters being born during these months.

It was very early on the 2 July that I was awoken by my distressed partner who had found two juvenile hedghogs out of the nest. One of the hoglets was clearly dead while the other was curled tightly into a defensive ball and noticeably breathing. On closer examination both had sustained severe injury to their faces. My partner had experienced trouble sleeping that night and had heard a lot of activity in the nest. There was a lot of shuffling and leaf scraping accompanied by swine-like snorting and grunting in the nest.

We called for the assistance of a Prickles Hedgehog Rescue who suggested we search the nest for other hoglets. It was then that we discovered a third hoglet that had suffered similar injuries and had died as a result along with the sow and surprisingly an adult hog. Infanticide by hogs is not well documented for European hedgehogs but is for other hedgehog species. By the time the five animals had been transported to the rescue centre, the third hoglet had died. Routine health checks and administration of antibiotics were carried out on both adult animals. They were both found to be in excellent health and had no visible injuries.

So what killed these hoglets in their nest within their first week of life? Well there are numerous possibilities but two stands out as the most likely. Firstly, a predatory attack from a small predator such as a European polecat (Mustela putorius) or a brown or common rat (Rattus norvegicus) that could gain access to the nest without destroying it. It stands to reason that any attack on a hedgehog will inevitably result in facial injuries as the face is probably the most vulnerable anatomy and first part to be exposed if a hedgehog is “unrolled”. However a predatory attack would logically result in some degree of consumption rather than just a fatal attack.

The second and, in my opinion, more plausible possibility is that of male infanticide. As with species such as lions (Panthera leo) males, having challenged for control of a pride, will kill cubs within the pride younger than about 9 months of age. The result is that the pride females will come into oestrus shortly after the infanticide allowing the males to mate with them. This is because most mammals do not ovulate while lactating. As males are in constant competition, those that carry out infanticidal behaviour will contribute a larger portion to the gene pool. Again the most likely anatomy to suffer injury would be the face as even hedgehogs are not immune to the spiny defences of their young.

After a few days of observation, we collected the adult animals from the rescue centre for release back into their natural habitat. You may be wondering what is natural about the garden habitat that they live in. However, the garden habitat is extremely important for the conservation of many smaller wildlife species. Gardens potentially contain extremely high levels of diversity with healthy soils high numbers of flora providing food and cover, high numbers of invertebrates again providing food as well as vital ecological functions such as pollination. Surveys carried out by the British Ornithology Trust amongst others indicate gardens recording the highest average number of wild mammals in typically urban areas. So suitable is our garden that we were asked to release another hedgehog sow into our garden because it suffered an attack from a dog in her home range.

Who would have thought that such an amazing story of survival could be observed in my garden in the city? Look carefully… I bet it occurs in your back yard too".






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