Drone used to count seals along coast in Natural England pilot project

A drone was used to count the number of seals along a stretch of the Norfolk coast in a pilot project by Natural England using artificial intelligence (AI) technology.

The organisation said the AI identified more than 8,500 seals, a higher number than a ground-level count by volunteers which detected more than 6,200 seals, possibly thanks to the bird’s-eye view of the drone.

The drone can capture images from 110 metres above, minimising disturbance to the seals.

A team from Natural England launched the drone over the beach at Winterton in December 2024 and used a type of AI called instance segmentation to detect individual seals automatically.

They also used the AI to distinguish between adult seals and white-coated pups, even when grouped closely together.

Natural England said its survey identified more than 8,500 seals along an 8km (five-mile) stretch of shoreline.

Gabriella Fasoli, Earth observation higher data scientist at Natural England, said: “The AI model detected over 8,500 seals while the volunteers on the ground counted 6,200.

“This difference is likely due to the drone’s aerial perspective, which provides a unique viewpoint from above, allowing for a more accurate count by detecting seals that may be hidden or less visible from the ground.”

While the new methods are described as having the potential to enhance the accuracy of counts, Natural England said volunteers on the ground would remain crucial to documenting and protecting seals.

Emma Milner, senior marine mammal specialist at Natural England, said: “This project has shown that drones and the use of AI technology can be a cost and time-efficient alternative method of monitoring seal populations.

“This cutting-edge technology will help contribute to a comprehensive national picture of seal populations, allowing us to better understand population changes over time and to assess the impact of human activity on these crucial habitats, enabling better conservation efforts.

“It is our hope that in the future, the methods from this two-year pilot project can be developed to allow drone surveys at other important sites around the country, and for other species as well as grey seals.”

The UK is a crucial breeding ground for grey seals, hosting 35% of the global population.

Despite their recovery from a worldwide total of 500 seals in the early 20th century to more than 160,000 today, ongoing monitoring remains essential to their protection.

Natural England has special permission to fly drones for the purpose of this scientific survey and followed best practice guidelines to minimise disturbance to the seals.

It stressed that members of the public should not fly drones over seal colonies without the appropriate permissions.