10 and 11 June 2013
On 10 and 11 June I visited Burhou, continuing the study of Lesser Black-backed Gulls breeding on the Channel Islands’ largest gull colony (c 1,200 pairs). The weather was difficult with cool easterly winds and drizzle cutting short the fieldwork especially on the morning of 11 June, but we did manage to colour ring another 31 new birds, while also re-trapping four caught previously (three on Burhou and one from Chouet landfill).
I also took the opportunity to record 43 colour-ringed LBBGs on the islet, along with six Herring Gulls. It was particularly pleasing to record a number of birds which had been ringed as chicks on the islet in 2009, 2010 and even one from 2011 (a year of virtual complete breeding failure for the gulls). Other surprises were an adult LBBG nesting on the island, which had been ringed in winter in Portugal, and a 2nd calendar year LBBG from Norway.
This year I am very excited that Vicky Warwick-Evans, who is undertaking a PhD on aspects of the ecology of Northern Gannets and European Shags nesting around Alderney, has extended the work to LBBGs. We trapped ten adults known to be breeding on the island, and fitted them with very small data loggers which will record their positions for five days or so. In this way we hope to learn where the gulls from this very important seabird colony feed. However, to do this we have to be able to recover the tags in a week or so, before they simply fall off and are lost (along with their valuable data).
Having flown up to Alderney (following last week’s aborted trip to Burhou after travelling up to Alderney on the Bumblebee ferry service), Tim Morley picked me up at 0800. I then had a slap up breakfast at the Braye Beach, before we got ready to cross on the AWT boat Sula of Braye. It was a lovely smooth crossing.
Roland dropped me on Burhou, along with Anne-Isobel and Aurelie of AWT, both of whom helped me throughout the afternoon’s gull trapping. Arriving on Burhou shortly after 12.15 pm we were trapping in the main colony at the western end of the island by 13.00. Chris Bale was also dropped off to undertake some professional photography work on behalf of AWT and the Living Islands initiative.
We managed to fit in nine rounds with five traps before we finished at 18.00, allowing a maximum of 20 minutes between rounds. We caught 23 adult LBBGs (including three retraps – adults ringed on Burhou in June 2010 and 2012, along with and with an adult caught at Chouet landfill in May 2013). Amongst the 20 other LBBGs caught was one which had been metal ringed as a chick on Burhou in July 2006.
Shortly before 18.00 Roland returned to Burhou with Vicky Warwick-Evans, Tim Morley and Phil Atkinson. They had been over on Les Etacs capturing adult Northern Gannets to fit data loggers, and had succeeded in fitting these recording devices to 27 birds. As the party landed Roland took Ann-Isobel and Aurelie back to Alderney. I had greatly appreciated their help with the gull ringing. This year some of the adult LBBGs seemed particularly defensive of their nests, with some impressive skua-like dive-bombing.
I changed focus from colour ringing LBBGs to capturing ten birds to fit with data loggers. We deliberately did this around the hut so as to make it as easy as possible to recover the equipment in a week or so. The first round went well with four birds in six traps, but we were then let down by a blank round. By the time we had to stop for the day we had caught eight adult LBBGs (which included one adult cr on Burhou in June 2010, and another bird metal-ringed as a chick on the island in July 2006).
Vicky finished the day with 100% of her tags on the Gannets and 80% on the LBBGs. Surely the last two birds would be easy to catch the following morning?! Well...nothing comes easily with seabirds! After some prolonged rain through the night, we awoke to more dreary, cold and at times wet weather. It was too bad to attempt nest trapping...so all we could do was drink tea...and wait...and wait.
Eventually it improved to a point where Vicky could go out and check to see if she could recover any of the data loggers previously attached to adult European Shags, but she has no luck (although she did catch one new adult). I managed to sneak out and record some more colour ringed gulls, making best use of the time.
Shortly before mid-day we got a weather clearance and set four traps behind the hut. However within minutes some drizzle swept in and we had to abandon the attempt. It was another two hours before we finally got our chance. The weather changed dramatically to give clear blue skies, sunshine and calm winds – a perfect day! We only had two hours before Roland picked us up again at 16.00, but working quickly we managed to catch the final two LBBGs for data loggers and a few extras for colour rings.
After a very smooth trip back to Alderney, Vicky ran me up to the airport in time for my 18.00 flight back to Guernsey.
All in all a very frustrating visit with a lot of down time...but in the circumstance we did very well, continuing to colour ring a sample of breeding adult LBBGs, record c 50 colour-ringed gulls including the wonderful sight of a number of Burhou raised chicks from 2009, 2010 and 2011 returning to their natal colonies...and of course all ten data loggers fitted to LBBGs on the islet!
12 June 2013