Alderney Gannetries

16th July 2007

  

With the Jetstream, and its associated plethora of low pressure systems, firmly in place across Britain for the majority of the months of May and June, the 2007 Seabird Season had proved to be the most difficult any of the current seabird enthusiasts could remember. Not only were there problems with strong winds, rough seas and plenty of rain on many days, but it was also difficult to secure boats during the relatively few calm windows of opportunity!

With the vast majority of the Channel Island European Shags taking a year out of breeding in 2007 (probably due to the very stormy weather in the early spring, which may have prevented the adults from finding enough food to reach breeding condition), and with breeding gulls and tern numbers looking low also, we were unsure how the Northern Gannets may have fared in 2007.

In view of the exceptional weather conditions and the unusual seabird breeding season, permission was obtained from the Channel Islands Ringing Scheme to extend the window to visit the gannetries until 16th July. This is some 16 days beyond the usual cut-off date of 30th June…which was put in place around 20 years ago. With the continued poor weather for most of the first half of July, it was looking like even this extension would not enable a visit to be made. However, at the eleventh hour a small ringing team of Catherine Kinnersly, Chris Mourant and Paul Veron managed to make the trip (on the very last day possible!).

The slight sea and light winds on the northbound sea journey from Guernsey raised hopes that we would be able to make a landing. Two European Storm Petrels were seen to the north of Guernsey. Richard Keen and other fishermen have been reporting larger than usual numbers of Storm Petrels around Guernsey and Sark this summer. It will be interesting to see what the autumn pelagics produce in terms of Storm Petrel numbers when they start in mid-August.

Having set off from St Peter Port Harbour at 1030, we reached the base of Les Etacs at around noon. There was a small swell at the base of the rock. Looking with binoculars we could see that the landing slope and edges of the colony contained mostly relatively small young with white down. However, further up the rock and into the main plateau (at the heart of the colony) we could see large young already in their very dark chocolate, white flecked plumage. Some were as big as adults.

From this, it became clear to us that the gannets had nested more or less on time in 2007. It was not a repeat of the late season evidenced in 2006. It was also abundantly clear that the gannets have been very successful in raising young in 2007.

Catherine, Chris and Paul landed at the usual place and slowly worked the landing slope and first gulley. We took our time and managed to ring 187 chicks. Almost all were covered in white down. None of the brown-feathered chicks was touched…and interestingly not one of them was seen to move even 30 cm from its nest. Some of the larger downy chicks were sprouting their brown wing and tail feathers – and some of these were mobile, but only in walking within a few metres of their nests.

We took an hour and a half to work very slowly up the landing slope and across the first gulley…leaving the upper and lower edges alone. When we reached the edge of the main plateau we stopped to take a good look. Here we could see lots of advanced young including many with their brown flight feathers well formed. We unanimously agreed not to enter the main part of the colony for fear of causing too much disturbance to these birds. We returned back the way we had come – again causing minimal disturbance. Most birds were already back on their nests.

One adult and several chicks were successfully cut free from nylon netting/rope. Although 5 or 6 dead adults were seen no rings were recovered on the rock this year.

Richard Keen picked us up, and rowed us to the adjacent stack. Here we climbed up the “chimney” to reach the main part of the colony. Another hour was spent slowly working our way through the birds. This area is not part of the main colony, and as expected the chicks were less advanced than in the main section. It was relatively easy to ring this rock, again causing very little disturbance. 103 chicks were ringed before we were picked up again.

With the tide having turned, Richard explained that landing on Ortac would not be possible. We decided however to go up to the rock to take a close look. This proved to be very worthwhile. As expected the nesting gannets on Ortac appeared to be a little behind Les Etacs with only a couple of fully-feathered brown youngsters seen from the boat. Most of the chicks observed were still covered in white down, although many were sprouting their brown wing and tail feathers.

Broad conclusions were similar to Les Etacs with the gannets breeding season being on time and very successful in 2007, despite the poor weather. The success of this species probably lies in the fact that it feeds on different fish species (i.e. not sand eel) and it can and does forage at considerable distances from the breeding colonies (unlike shags, gulls, terns and auks).

Although only 290 chicks and one adult were ringed on the trip, valuable data was obtained.

As an aside…for the second (third?) year running, we are convinced that gannets are attempting to nest on one of the westernmost outlying rocks of Renonquet. The top of the rock is very white and 30+ adult birds were seen circling over the rock. It is very difficult to get close to the rock, as it is circled by a dangerous reef. However, even if nesting is being attempted, it is most unlikely to be successful as this rock is very low making any nests very susceptible to storm surge and spray.

On the return boat journey we saw a first year gannet flying west very strongly and purposefully behind an adult. Whether this bird was one of the first young to leave the Alderney gannetries or had its origins further north is a matter of mere speculation. What was clear is that it looked mighty fine on the wing!




20th July 2007


PS – On 29 July Paul passed close to Ortac and Renonquet returning from the UK on Condor Ferries. Although he did not have binoculars he saw 50+ gannets standing on the two rocks to the west of Renonquet, and many looked like they were attempting nesting – even though the rocks are restricted in height above the sea. It really does look like gannets are now spilling over from Ortac (which appears full) to try to establish a new colony off Alderney. Let’s hope they find a more suitable rock very soon!