Burhou

9 - 11 July 2009

         
The Guernsey Seabird Team, consisting of Chris Mourant, Paul and Catherine Veron, headed up to Alderney on Thursday 9th July with the aim of getting onto Burhou to colour ring Lesser Black Backed Gulls chicks.  They were met at Alderney airport by Roland Gauvain and Afra Skein of the Alderney Wildlife Trust (AWT).  There was time to pick up provisions and also enjoy a cup of tea and a chat at the AWT headquarters before going to the harbour at 17.15 for a quick trip across the Swinge in the AWT rib "Sunrise".  Owing to new regulations it was necessary to use a coded skipper for this journey and we are therefore grateful to Dave for providing this service.

Once established in the hut the team decided to take a few rings and explore the northern end of the island where few gulls nest, so as not to disturb any of the main colonies.  The first gulls ringed were three Great Black-backed Gull chicks, followed by eight Lesser Black-backed Gull chicks (seven of which were large enough to also take colour rings).  The team then retreated back to the hut for a basic supper before getting an early night.  As ever, it was very special to spend a little time on the islet, where the only sounds were those of the very noisy gulls and the gentle running of the sea.  A near full moon ensured that it never really got dark.

The next day we rose at 05.30 ready to begin an intensive day working methodically through the gull colonies in search of suitably aged chicks.  After Paul and Sophie Veron's trip in July 2008, when they had discovered only three chicks raised to near fledging, from the circa 1,000 pairs breeding, the team was very uncertain as to what it would find.  However, it soon became obvious that the gulls in 2009 had made a most welcome return to form, with plenty of evidence of successful breeding.  

The team began ringing gull chicks in the area in front of the hut, working its way carefully through the bracken to the eastern shoreline, and then along the south east coastline, which holds the first half of the main colony of  Lesser Black-backed Gulls.  

It was interesting to note that while the majority of chicks were sufficiently large to take colour rings, none was fully grown, and Paul estimated that it would be at least another 10 - 14 days before any of the Burhou Lesser Black-backed Gull chicks fledged.  This, despite the fact that he had already seen juvenile Lesser Blacked-backed Gulls  on the wing both off Guernsey's south coast cliffs, and at Chouet Landfill site, Guernsey.  He speculated that the later breeding season on Burhou (compared to Guernsey, Sark and Herm), is further evidence that the Burhou colony is acting as a truly wild colony with the majority of adults taking natural food or fish waste rather than feeding in towns or on landfill.  This was further backed up when chicks were only seen to regurgitate fish during the ringing process.  There was no evidence that the Burhou gulls are feeding on man's organic waste.

Chris, Paul and Catherine worked steadily through the colony noticing that the adult gulls returned to their chicks extremely quickly once we had moved a short distance further on.  Both Chris and Paul remarked on how the Lesser Black-backed Gulls appeared to be spreading even to the rocky outcrops and tops of the storm beaches; areas which in the past had been occupied by Herring Gulls.  The team was surprised at how few Herring Gulls appeared to be nesting on the islet (only eight chicks were ringed on the entire visit).

Once the first half of the main Lesser Black-backed Gull colony had been ringed, the team took a much needed refreshment break before returning to complete the job.  By the time the team reached the end of the colony - 227 Lesser Black Backed Gull chicks had been ringed.

At low tide, it was possible to make a very quick visit to Little Burhou where a further 19 Lesser Black-backed Gull chicks were ringed along with three Shag that were still in their nests.  An additional two Great Black-backed Gull chicks were colour ringed on the islet.

The team finished the day checking the rock outcrops and bracken outcrops to the west of the hut ringing another 29 Lesser Black-backed Gulls. By the end of another exhausting but very successful day the total number of birds ringed was:-

Lesser Black-backed Gull        281  (218 colour ringed)
Great Black-backed Gull            5  (all colour ringed)
Herring Gull                                8  (one colour ringed - the last colour ring available)
Shag                                           4

                                                 

The following day was damp with intermittent light showers and the team decided that to minimize disturbance to the Gull colonies they would restrict their movements to the hut area only with one short foray up to the north of the island.  Following the predation of 20+ European Storm Petrels in this area during the summer of 2008, they were pleased not to find any evidence of such predation this summer. They did, however, find several Peregrine kills - Common Wood-Pigeon, Feral Pigeon and (surprisingly given that there are no magpies on Alderney) a single Eurasian Magpie.  The team was also lucky enough to observe a spectacular fight between a pair of Buzzards and a pair of Peregrines over the rocky outcrops to the north of Burhou.  The Peregrines were obviously less than pleased to be sharing their hunting grounds with the Buzzards and made it absolutely clear who was the top predator in the ecosystem with the Buzzards chased off back to Alderney.

The team was also pleased to have good views of the Atlantic Puffin colony from the hut with 12 - 15 adults stood on the grassy turf outside their burrows for some time and rafts in the bay of up to 150 birds at any one time.





Catherine Veron

14th July 2009