Observations of the seabirds, which are large and bright white with black wingtips, have revealed a marked change in how they have been hunting for food.
Alderney Bird Observatory warden John Horton said years of documentation showed how many ocean-going birds follow fishing trawlers to take advantage of waste or surplus fish discarded by these vessels. However, with Atlantic fishing currently restricted due to lockdown the birds were having to find their food elsewhere.
‘I was witness to this myself in January this year, experiencing days at sea on a cruise
ship seeing no seabirds at all until we came across fishing trawlers off the Spanish and French coasts, each being followed by hundreds or even thousands of seabirds, many of them gannets,’ he said.
‘Now with the lockdown effectively ending the Atlantic fishing trade, this reliable and more easily obtained food source for gannets and many other seabirds has suddenly dried up.
‘From my observations the immediate knock-on of this, certainly around the Alderney coastline, is seeing good numbers of gannets hunting and diving for food immediately offshore.’
Regular recent sightings confirmed to Mr Horton his theory was supported.
‘I was able to take photographs from my garden at Mannez lighthouse of gannets diving into the sea, something I have seen only a handful of times before from this location, but always with the necessary assistance of binoculars or a spotting scope,’ he said.
‘At present, the spectacular experience of these birds in action is a regular sight off and on daily with the birds, so close optics are not required.
‘Even on Alderney, during a normal year it is unusual to see any gannets travelling overland, right now and for the last few weeks I am observing gannets flying across and over Alderney everyday, suggesting a marked change in behaviour away from the birds following the coastline some distance offshore.’
He added that the uncharacteristic gannet findings of La Societe Guernesiaise’s Jamie Hooper, who has been involved with Bailiwick gannet research since the 1990s, in Guernsey backed up his own observations of the birds in Alderney.
‘Jamie reported seeing two gannets further inland in Guernsey than he could remember ever seeing them before – this tied in nicely with my own observations locally in Alderney,’ he said.
‘Whilst we are very lucky to have a gannet colony occupying two – Les Etacs and Ortac – of the offshore islets and gannets passing by the Alderney coastline almost all year round, it remains to be seen what kind of impact this significant deviation from these birds' routine will have on their breeding success and potentially the survival rate of this year’s chicks.’
The Alderney gannet colonies, largely thanks to bird ringers from Guernsey undertaking research since 1946, are one of the world’s longest-standing ongoing seabird studies.
Alderney Bird Observatory leads gannet chick ringing research trips annually around mid-July and it is hoped their work later this year may be able to provide important data in connection with the suspected reliance of gannet colonies on commercial fishing.