Burhou

13-15 June 2008

 

Just before 4 pm on Friday 13th June, Catherine Kinnersly, Paul Veron and Chris Mourant left St Peter Port on board the Margaret K, skippered by owner Richard Keen. The Jersey contingent of Ian Buxton and Tony Paintin had flown up to Alderney during the day, and would be brought across to Burhou later by the Alderney Wildlife Trust in its small Dory – Nomad. The two-hour journey up to Alderney was largely uneventful. Before crossing the Swinge to Burhou, Richard hauled up under the Garden Rocks to take a look at the Gannetry – in advance of our planned visit the following week. Several chicks could be seen, although as is typical most adult birds were in close attendance to the nests making it very hard to see the age of most of the youngsters from the boat. In terms of size the colony certainly looked as busy as ever.
 
We landed in the gulley in front of the hide, and carried our gear up to the compound. The Alderney Wildlife Trust had three researchers on the islet who were all leaving as we arrived (picked up by Nomad). As Richard steamed off back to Guernsey Catherine, Paul and Chris enjoyed a cool drink amongst the ambience of the gulls nesting close to the hut. Ian and Tony arrived within the hour, and after settling in we all set off to the east end of the islet to erect the eight mist nets. We replicated the net runs used by the Storm Petrel Teams in 2003, 2005 and 2006 – which meant having a line of 4 x 18 metre nets on the far side of the ridge and 3 x 18 m nets on the Alderney side, with an isolated 18m net at the bottom.
 
As the light faded a Rock Pipit opened the ringing account. What followed surprised every member of the team in that it was very busy. We had mounted the expedition a full month earlier than usual to meet the request of the Alderney Ramsar Site Management Plan (as advised by AWT and the RSPB (Mark Bolton). The idea was to try to avoid catching wandering birds and therefore obtain better data for trying to asses the true size of the breeding colony of Storm Petrels.
 
The first birds were caught at 2240 – despite the bright light given out by the more than half full moon. Petrels could be seen flying in very fast, and Catherine heard one churring from the granite rocks just behind the ringing/release site. From 2300 the activity was so strong that the team furled the single 18 metre net, especially as for every bird being extracted from that net at the time two were being caught. This net remained furled for one and a half hours before the team was able to safely open it again. Peak activity stretched from 2300-0100, but birds were being caught right through until the light began to show in the eastern sky.
 
By the end of the night some 92 new birds had been caught, along with a similar number of retraps. Four foreign-ringed birds were also controlled – three French-ringed birds (from Banneg and Beniquet islands in Finistere, France) and one British bird (originally ringed at Pendeen Watch in July 2005).
 
After such a busy night the team returned to the hut for several hours’ well-earned sleep. Then it was time to try out the newly made colour rings for the Lesser Black-backed Gull project which Paul was commencing in 2008 across the Bailiwick. Ian had brought up a Gull Trap in his luggage and within a few minutes he had it set over a suitable nest. The parent bird duly obliged and was ringed and released within a few minutes. The new ring looked very good on its leg – both small and closely fitting but easy to see in the field. Paul had made up four rings and the Team therefore caught four adult birds to begin the study. Hopefully it will really begin in earnest when Burhou was visited again in mid July to ring the gull pulli.
 
In keeping with the request from the AWT, the Team did not wander around the island during the daytime. Instead everyone rested in the hut compound, awaiting the second night. Just before dusk the team erected the eight 18m nets in the same runs at the western end of the island as have been used in the previous ringing expeditions. A second very hard night’s work ensued – with the five ringers being kept very busy through the night. As the team packed up the nets in the morning another 107 new birds had been caught, along with c 100 more retraps and a further French-ringed bird (from Banneg, Finistere).
 
The success of the trip with 199 new Storm Petrels ringed and more than 200 retraps (some from the same evening) made all the efforts highly worthwhile. Once the database of retrap histories had been calculated, Paul would send the database to Mark Bolton and Phil Atkinson to see if the new data, obtained in mid-June, threw any more light on the probable size of the Storm Petrel nesting colony.  Phil subsequently informed the Team that the data indicates a population of c 1,000 birds - considerably larger than thought during the last national seabird surveys in 1998/2002.
 
Although the island was not searched, it was noted that the Shags had failed to nest successfully (as they had across the Channel Islands in 2008). Two predated Storm Petrels were found by the team – one along the central ridge west of the hut and the other in the Puffin colony at the east end. None of the team had ever seen this before on Burhou. After the visit AWT discovered what it believed to be the remains of at least nine birds – mostly by the ridge at the back of the Puffin colony on the east end. Such predation is potentially a serious issue for the small colony. AWT is undertaking further work to try to determine the predator involved.
 
Of interest no live rabbits were observed during the two day stay, although several rotted carcases (victims of myxomatosis were observed). The lack of rabbits has certainly resulted in very lush vegetation, although whether this is beneficial for the seabirds is open to question.
 
Another interesting observation was a Northern Wheatear seen at the east end.  It is possible that this bird was breeding on the island.
 
By the time Richard Keen arrived at 0600 on Sunday 15th June to pick up the Team we were all very tired. Ian and Tony were dropped back at Alderney harbour so that Tony could make the return flight to Alderney, while Paul, Catherine and Chris motored back to St Peter Port with Richard. All in all it had been a very successful trip with surprisingly strong results.