The National Trust has used drones and thermal imagery technology for the first time to help verify seal pup numbers at one of the largest grey seal colonies in England.
Rangers who work on the Farne Islands, off the coast of Northumberland, have traditionally counted the seals every four days using dye, and in 2018 used a drone for the first time to help verify numbers.
This year, the rangers are working with researchers at Newcastle University, Oxford University, the Sea Mammal Research Unit and TerraDrone to continue trials counting the seals with a drone that uses two separate cameras. One camera films the seals from above as visible with the naked eye, and the second uses a thermal imaging camera.
According to the project, using drones to monitor and count wildlife is a relatively new practice but it allows conservationists to look at large areas easily and quickly and count whole populations rather than just a sample. It is also less intrusive and stressful for the animals than the close interaction of human led surveys.
Furthermore, the use of drones also enables the team to count pups on outlying islands in difficult conditions.
Using computer-based machine learning on the drone photography then makes the surveys quicker, more cost effective and more accurate than was previously possible.
Ranger Thomas Hendry, said: “The drone gives us an excellent view of the islands and from the clear images we can count the total numbers of seal pups born on each island. It also allows us to see onto the smaller islands more frequently which can be more challenging to visit at this time of year due to difficult sea conditions.
“Having the extra thermal imaging technology is particularly useful now that the islands are supporting more and more pups and the population is denser. It will hopefully also allow us to detect any seal pups that sadly don’t survive, so that they aren’t accidentally included in our numbers.
“As the footage is taken whilst we are carrying out a visual count, we can compare different counting methods to check against the numbers we get on the ground.”