Drone footage of a large heronry could shed new light on bird populations across the country.
Remarkable footage shot at the Woodland Trust-owned Parrs Wood at Grappenhall Heys in Warrington, Cheshire, shows 18 nests perched precariously in the top of trees.
The coverage was shot on behalf of Brian Martin from the British Trust of Ornithology by Serge Wich from Liverpool John Moores University and it is thought to be one of the first such studies done by drones on herons in the country.
Mr Martin writes hat the study has the potential to transform data on bird populations both here and across the UK:
“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 ten 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 adds: “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.”
The National Census of Herons is the oldest census of any bird species in the world – running since 1928. The latest population figures for Grey Heron in the UK from 2015 is in excess of 11,000 pairs but Mr Martin, who has studied herons since 1980 and coordinates census gathering in Cheshire, thinks that number could be considerably higher following the discovery at Grappenhall Heys.
Herons breed colonially and tend to return each year to the same breeding site. They generally produce a clutch of three to five eggs. Both male and female herons feed the young so there will be two adults per nest. The young fledge when six to eight weeks old. They like to be near wetlands and feed mainly on fish but also frogs and small mammals. Grappenhall Heys Wood is within 2 miles of a large wetland where many of the adults obtain their food
One of the largest heronries Mr Martin has come across is at the Duke of Westminster’s Estate near Chester where there are more than 100 nests.
Images/Footage © Woodland Trust/British Trust for Ornithology