By Denis O’Connor

Wharfedale Naturalists Society

One of my New Year resolutions was to locate some of Yorkshire’s adders, widespread but elusive across miles of uplands.

Knowing that adders now emerge from hibernation earlier, I optimistically started my search in mid-February in an area within the Washburn Valley known for adders. Perhaps I was not sufficiently sharp-eyed or maybe they were still snoozing underground but I eventually gave up – this was needle in a haystack stuff!

Another try in late March brought similar negative results. I therefore sought more expert advice and got directions to a hibernation site. Adders often hibernate communally underground, coiling together to preserve body heat.

Arriving there on 30th March on a cold sunny morning I slowly patrolled fences and broken-down stone walls. I was becoming discouraged when I looked down and suddenly there were two intertwined adders. Three more paces and I might have trodden on them producing problems for all three of us!

They were joined by a third and I watched them for two hours while they basked in the sun coiled round one another with flattened bodies, occasionally moving away rather jerkily before returning. All three were females (pictured), the males being more black and white.

Returning on 10th April I found maybe the same three although spread over a greater distance and more active than previously after an hour basking in the sun.

On 22nd April I tried again but away from the hibernation site, by coincidence searching the same south-facing slope featured in the BBC’s Countryfile programme of 25th April, part of a wider area where teams from Nidderdale AONB have been doing adder surveys. I found no adders where they had found just one.

Interviewed on the programme, Wharfedale’s adder expert, David Alred, described how on one day some years previously he had found 37 adders. In the week before the programme he had only found one.

I had heard a similar story from the area’s gamekeeper who told me that, going back ten years, on the slope I had been searching it would not have been unusual to see 15 adders in a few hours.

It is difficult to attribute the decline to just one factor. In our area, planting of conifers 20 to 30 years ago destroyed significant adder habitat while persecution, predation, disturbance and inbreeding have also played parts. Perhaps most important is climate heating, for early emergence from hibernation means adders are more susceptible to the return of cold weather following a warm spell.

wharfedale-nats.org.uk