Burhou, Alderney

30 May – 01 June 2014

After a short mid-morning flight up to Alderney, I enjoyed wonderful aerial views of a very busy Les Etacs gannetry as we descended over Alderney’s west cliffs. Tim Morley picked me up from the airport, and dropped me in St Anne’s where there was time for coffee with some of the Alderney Wildlife Trust’s 2014 Team. I then wandered down the hill and grabbed a fish and chip lunch before boarding the Trust’s boat Sula…and heading out across the Swinge. On this trip the three people undertaking the seabird work were Tim Morley, Vicky Warwick-Evans and me.

The sea was wonderfully calm, despite the rather cool overcast conditions. Once on Burhou we baited the cage trap and then while Tim and Vicky completed some Atlantic Puffin counts, I went up to the central ridge to record gull colour rings.

The priority for this trip was completing a full island gull nest count, as this had not been done for the previous two seasons (for various reasons). At the same time I wanted to use the time to record some of my Lesser Black-backed Gulls which had been colour ringed in previous seasons, and then thirdly trap a few more adult gulls to keep the sample of colour ringed adults going.

After a few hours’ observation I managed to read 51 the colour rings on LBBGs and 16 Herring Gulls. This is very valuable data for the gull research as these records refer to birds on a breeding colony.

After a noisy night with the gulls thundering about on the hut’s roof, and fighting in full voice, we were up early to try to take a catch of full grown gulls in the cage trap. However, despite much interest in the food no gulls entered the trap while set, and after three fruitless hours we unset the trap and began the main task for the day – the whole island gull nest count.

The nest census involved the three of us walking quickly, but carefully through the gull colonies marking each nest counted with a pasta shell (to avoid double counting). While Vicky and I called out the contents of each nest observed, Tim recorded the details, while also counting nests himself. The census proved to be hard work, especially when the clear blue skies and light winds got the temperatures rising.

It was clear that the gull populations looked to be as strong as ever on Burhou, and this was confirmed when Tim tallied the day’s figures over supper. The result was a total of 1,423 nests, which included about 30 Herring Gulls, plus a further six Great Black-backed Gulls nests.

Two of the GBBG nests contained chicks a day or two old, as did three of the LBBG nests, but otherwise every nest was either empty (236), or with eggs (1,184). The total number of eggs counted was 3,078, and clutches were three eggs (819 or 58%), two eggs (250 or 18%) or one egg (115 or 8%). 236 nests (16%) were empty and were probably nests built by adults not laying eggs (but retaining their breeding territory) in 2014, or by gulls not yet fully mature to breed.

While working through the main colony received a telephone call to inform me that my return to Guernsey the following day on Bumblebee had been cancelled, so I had to re-arrange to fly back to Guernsey. This meant leaving Burhou a few hours earlier than originally planned.

During the late afternoon, after a quick cup of tea, we baited the cage trap again and after much adjustment and frustration, we did manage to trap five new adult Lesser Black-backed Gulls. While clearly having potential for use on Burhou, the cage trap experience was not entirely successful on this trip.

While I recorded gull colour rings for a few more hours before nightfall, Tim and Vicky did another puffin raft count and reached 190 birds. While this is a very good count, some caution is needed at this stage because it would appear that not only did the puffins arrive around a month late on Burhou this year, but few appear to be actively nesting this season so far. Whether they will try now and run into a very late season, or simply not breed remains to be seen. However, if one of the pair was not down the burrow incubating an egg, then a count of 190 birds in the evening raft may not be as healthy as it first seems. Given the large seabird wreck in the region in February this year, when half of the 35,000+ birds killed were puffins, it would not be surprising if many of the adults returning to Burhou this summer were not in good enough condition to breed this year. Only time will tell.

My gull colour ring tally for our only full day on Burhou was 64 LBBGs and 13 Herring Gulls. In addition today, while wandering through the colonies we had found the remains of 31 adult Lesser Black-backed Gulls killed by the local Peregrines. Of these gulls three had been ringed as chicks on Burhou (one in July 2009 and two in July 2010).

Our final morning on Burhou dawned another beautiful calm day. The view across the Swinge to Alderney and Les Etacs gannetry was particularly mesmerising. Instead of trying the cage trap again, we decided to do some quick nest trapping of LBBGs around the edge of the hut colony. In the few hours available we managed to catch and ring 11 new LBBGs, as well as re-trapping two birds which had been ringed as chicks on Burhou in July 2010 (and thus were breeding in their fifth calendar years).

All too soon, Sula appeared on the horizon and we rapidly packed our gear and rowed back out to AWT’s boat. It was a really lovely calm crossing back to Braye Harbour. After a well-earned beer with Tim and Vicky, Tim dropped me back at the airport for my 15.45 return to Guernsey. The homeward flight also gave wonderful views on Burhou and Les Etacs, with Ortac gannetry and Les Casquets lighthouse in the distance.

With the first whole island gull nest count completed for three years, all egg clutch sizes recorded,  c 140 gull colour ring reads, 16 new adult LBBGs colour ringed, and some more valuable puffin count data achieved this had been a very successful and enjoyable visit to my favourite seabird colony in the Channel Islands!

Appended is a summary of the origins of the colour ringed birds recorded on Burhou during this visit.

 

PKV

02 June 2014

                    

 

Summary of Gull Colour Ring Reads – Burhou 30 May – 01 June 2014

Lesser Black-backed Gulls

48 chicks ringed on Burhou, Alderney in 2003 (one), 2006 (one), 2009 (20), 2010 (20), and 2012 (six).

41 ringed as breeding adults on Burhou, Alderney in 2009 (ten), 2010 (six), 2011 (ten), 2012 (nine) and 2013 (six).

Two adults ringed in winter at Gloucester, England in 2004 and 2008.

Total = 91 birds

Plus Killed by Peregrine - chicks ringed on Burhou, Alderney in 2009 (one) and 2010 (two).

Total = three birds

 

Herring Gulls

Six chicks ringed on Burhou, Alderney in 2005 (one), 2010 (three) and 2011 (two).

Two chicks ringed at Pleinmont, Guernsey in 2004 and 2005 (one each year).

One chick ringed at Les Ecrehous, Jersey

15 ringed as full-grown in Guernsey in 2010 (one), 2011 (five), 2012 (two), 2013 (six) and 2014 (one).

One ringed as full-grown in Gloucester, England in 2007.

Total = 25 birds