Footage of nesting herons shot by a drone could shed new light on bird populations across the country, conservationists have said.
The footage of the heronry filmed at the Woodland Trust-owned Parrs Wood at Grappenhall Heys in Warrington, Cheshire, shows 18 nests perched in the tops of trees.
It could provide a more accurate assessment of the number of nests used by herons than estimates made from the ground, experts said.
Mr Martin said: “By counting nests from the ground and deciding from discarded eggshells and droppings on the trees and surrounding vegetation we can estimate how many nests were occupied.
“This, however, is by no means accurate and some used nests may be overlooked.
“Earlier this year, following such a survey, we estimated there were nine nests in Grappenhall Heys, but now with this new drone footage above the nests, we have a more accurate way to measure populations.
“We can get within 10 metres of the nests without disturbing the herons and are even able to see the young chicks.
“These results show the actual population is double that which was previously estimated so it could be a pioneering study.”
Neil Oxley, site manager at the Woodland Trust said: “This is the first such footage we have ever had at one of our sites and it is exciting.
“We have known for many years that herons nested at the site but have never seen it in this light.
“It would be remarkable if this footage at one of our sites pioneers a new way of estimating both bird and animal populations.
“It would also be interesting to potentially uncover other heronries at our other sites.”
A national census of herons, the oldest census of any bird species in the world, has been running since 1928, and the latest population figures for grey herons in the UK, from 2015, is more than 11,000 pairs.
But Mr Martin, who coordinates census gathering in Cheshire, thinks the number may be much higher following the discovery at Grappenhall Heys.
Herons breed in colonies, generally returning each year to the same site, and like to be near wetlands to source their main food of fish, but they also eat frogs and small mammals.