Sark Asian hornet nest one of the largest found in Bailiwick
AT LEAST 200 Asian hornet queens have been prevented from creating more colonies on Sark with the removal of one of the largest secondary nests found in the Bailiwick to date.
The Asian Hornet Team made the trip over to Sark on Wednesday after months of liaising with local beekeepers Peter Cunneen and Jo Birch, trapping hornets to narrow down the nest’s location.
Francis Russell, Asian Hornet Strategy project coordinator, said: ‘The size of the nest there could be over 200 queens that have been prevented from continuing to exist on Sark.
‘And in the ten or so traps placed around the nest we caught a further 300 hornets. When the queen comes out of hibernation she builds a small nest and raises a small band of workers 30-50 – the nest that she has built herself is called a primary (or first nest).
‘Later on when the workers then take over building the nest it becomes much larger and gets progressively bigger over the summer/autumn.
‘It can be very large, containing 5,000 hornets or more, usually found up in the tree tops. These larger nests are called secondary – it is the main nest from which the new queens are raised. The one on Sark was a typical large secondary nest although unusually it was low down in brambles.’
Mr Russell said the team got the call through its hornet mailbox where can people report sightings to the team from anywhere in the Bailiwick.
The Asian Hornet Team were aware of Asian hornets on Sark and had been notified of at least 20 sightings over the course of this year.
‘There had been about 10 queens sighted around Sark in the spring and even one which was found to have drowned in someone’s pint of beer near the Bel Air. We noticed a 10-week period in which there were no sightings on Guernsey but repeated sightings on Sark over June time. If there are hornet sightings in June this means that a queen has rested somewhere,’ said Mr Russell.
n 3 June: Asian Hornet seen flying at Bel Air pub.
n 2 August: Asian Hornet caught at Aval du Creux.
n 23 August: Asian Hornet found drowned in pint near Bel Air.
In late summer, Mr Russell and Damian Harris, field and research officer for the team, went across to Sark to begin tracking down the nest.
Unfortunately, the nest was not located but the team had a good idea of its rough location.
By putting up bait stations and moving them gradually closer to the working line of the hornets it is possible to ‘loosely triangulate’ the nest’s position.
After some weeks the beekeepers had singled out a chestnut tree which they thought contained the nest. When discovered near the base of the chestnut the nest was 45cm wide, 50cm tall.
It was inland from Derrible Bay, about 200m south of the Aval du Creux Hotel and Harbour Hill, in brambles under a fallen tree root.
‘Damian and I travelled over again on Wednesday to remove the nest on request of the Sark Agriculture Department. Damian treated the nest with pesticide and then we returned four hours later to cut it away. It was double bagged and has now been returned to Raymond Falla House for dissection and analysis. At this point in time we are just trying to work out what we have found. The size of it there could be at least 200 queens prevented from building more nests,’ said Mr Russell.