IT IS a rare privilege to spot an otter in the wild.

Anyone who has seen one of these elusive mammals will bear witness to the wonderful spectacle, particularly to see one slinking into a river or swimming like a dart through the water.

Regular reports of otter sightings have been recorded along the River Aire, increasingly so since work to create new otter holts and enhance existing habitats as part of the Mid Aire Otter & Rivers Project.

The project worked on five different sites along the Aire Valley between Bingley and Kirkstall, Leeds, including Apperley Bridge, Denso Marstons Nature Reserve at Shipley, Buck Mill at Thackley and Rodley Nature Reserve on the outskirts of Leeds.

The aim was to improve habitats along the valley for otter and other wildlife, control invasive non-native species such as Himalayan balsam and Japanese knotweed and increase the monitoring and surveying of the otter population along the river corridor.

Work included the clearing and restoring of scrapes - relatively dry sites where otters roll and groom - ponds and river channels, the maintenance of reed beds and meadow, building willow river bank fortifications and repairing bridges and boardwalks.

Twenty otter holts were installed as well as 100 meters of ‘dead hedge’ otter habitat. Around 2600 trees were planted along the banks and vast swathes of invasive plant species cleared. Work has been ongoing since the original two-year project ended in 2007.

“We have recently refurbished a couple of our original artificial otter holts that were damaged in the 2015 floods,” says Don Vine, conservation officer with Yorkshire Wildlife Trust. “There now seems to be a stable otter population on the Aire and its tributaries with regular reports of sightings and signs along the whole length of the river, including a sighting in Leeds city centre in February.”

He adds: “Although we have no direct monitoring of otter populations we revisit many of our project sites to see look for signs around. On some sites where there are active local groups we receive constant feedback.”

The YWT has also run seven otter identification training courses for 70 volunteers to produce survey information along the Aire Valley.

“Our ongoing projects in this area also provide the opportunity to monitor otter populations from time to time and allow us to build on the success of this project with similar initiatives,” says Don.

“We depend on those who are out and about, such as anglers and canoeists, however it is sometimes difficult to confirm a sighting especially as there other species such as invasive mink throughout the Aire Valley, but we are confident that many of the reports are accurate.

Some of the project work has been built on through other schemes, in particular work to protect and manage wet woodland - poorly drained or seasonally flooded areas - and other schemes in conjunction with the Environment Agency, looking at mapping and dealing with invasive plants.

Work to attract otter also benefits other wildlife. “As the otter is one of our top native river predators and is dependent on other species all along the food chain, they are good indicators of the health of watercourses,” says Don.“You will not get otter in areas where there is little or no aquatic life. In addition, the enhancement of bankside habitats for otter will have indirect impact on other species. For example wet woodland is important for wildlife including rare crane fly species, birds such as willow tit and marsh tit, and pipistrelle and brown long-eared bats. Tree and shrub planting on river margins creates shady areas for fish and cover for amphibians.”

Volunteers are vital to the success of every project and more than 2,500 have been involved in the otter and wet woodland work alone. “Without them none of this would have been remotely possible,” says Don.

“The trust also engages with schools, colleges and universities and community groups,” says Don, stressing the vital role played by partner organisations including Bradford Council, Denso Marstons, Rodley Nature Reserve, the Environment Agency, British Waterways and Bradford Environmental Education Service.

The trust is currently looking towards natural flood management in the Aire Valley, using natural processes such as flood storage in wetlands, tree planting and log dams to help slow the flow of water from the uplands into the main river channel. There are biodiversity benefits - creating and enhancing new upland and riverside habitats.

“We are currently investigating potential sites both on the Upper Aire and also along the middle reaches within the Bradford boundary,” says Don.

For details of volunteering opportunities visit ywt.org.uk/whats-on