By Denis O’Connor

Wharfedale Naturalists Society

In the mid-twentieth century otters, which had been widespread throughout Britain were decimated by two lethal threats. The first was the “sport” of otter hunting with hounds. The second, less obvious but more devastating, was poisoning by organochlorine pesticides similar to DDT, widely used in agriculture and which leached off the land into rivers, concentrating in the bodies of top predators like otters with fatal results.

In Wharfedale, according to WNS records, “In 1948 otter tracks and one otter were seen near the toll bridge in Ben Rhydding then nothing until the mid-nineties when the Yorkshire Wildlife Trust Otters and Rivers Project began surveying the Wharfe and evidence was found that otters had at last returned to the river.”

In 1998 a project led by YWT built man-made holts in Upper Wharfedale to help the tiny population establish new territories.

By 2008 otter spraint (droppings used to mark their territories), tracks and fish remains were being regularly reported from Otley Wetland Nature Reserve and from the Washburn Valley but with only very occasional sightings.

This pattern carried on until in 2016 WNS reported, “many sightings, including juveniles, confirming the presence of a resident breeding population on the Wharfe.”

This upsurge in sightings has continued to grow so that in 2019 there were eight records of live otters from Wharfedale. This year so far there have been an incredible 21 sightings from Hebden southwards, including three otters once and two on four occasions.

Although industrial and agricultural chemical pollution has improved on the Wharfe in recent years there continue to be problems with the discharge of raw sewage, particularly at Ilkley where it appears a fairly routine event rather than an exceptional one caused by heavy rain.

A pollution free area and perhaps the most important otter site over the years has been Otley Wetland. For many years live otters were elusive there although they regularly left signs. They have been seen there a number of times this year, although not by me. However, technology came to my aid and twice this autumn I have set up a trail camera there overnight, pointing at a log known to be used as a spraint point. On each occasion it recorded several otter visits (see photo, with the otter’s eyes reflecting back the invisible infra-red as visible light).

Otters seem to be well and truly back in Wharfedale.