26 June 2014

The second visit of the season to Jethou, with the kind permission of Dr Ogden, and the very helpful co-operation of Bill Bayley, was reduced to an even smaller Seabird Monitoring Team of Paul, Catherine and Merlin Veron.  A grey and still day with the prospect of light showers promised cooler working conditions for the team, who travelled across to Jethou at 0800. The priority for this visit was to colour ring gull colonies (Great Black Backed and Herring Gulls). 

As the tide was still falling, with low water not until 1pm approx, the team first headed to the grassy slope on the southwest coast which traditionally holds a good breeding colony of Great Black Backed Gulls.  Whilst walking along the cliff path to this colony we observed nine Atlantic Puffins sitting on the water in small rafts near   Grande Fauconniere.  A Common Fulmar was also noted close in.  Numerous meadow brown butterflies were disturbed along this pathway as well as several Grayling butterflies, warming up in the morning sunshine.  Paul and Catherine then began the search through the grassland both above and below the path for Great Black Backed Gull chicks. An impressive total of 18 chicks were colour ringed, along with a single Herring Gull chick.   Several of the usual European Shag nest sites in this area had obviously been used as fresh material was in the nests but there were no signs of eggs or chicks.  Only one nest site was found with 2 large chicks.

The team then had a quick coffee break back at the harbour to revive us before setting off to Burner Beach where a total of 17 Herring Gulls was colour ringed (plus one metal ring only as the chick was too small for a colour ring).  The team then decided to head for Crevichon where a further two Great Black Backed Gull chicks and one Herring Gull were colour ringed.  Two corpses of young Little Egrets were found in the quarry entrance, along with a colour ringed Great Black Backed Gull chick on the first promontory on Crevichon. These birds had probably fallen to rat predation.  The Egret colony still held young but was not approached and there were a couple of productive Shag nests around the pepper pot at the top of Crevichon, each with two young.

The team then returned to the beach in front of the house and began their search for Herring Gull chicks; a total of 20 was colour ringed.   Given the large chicks further along the beach, one section was missed out to avoid chicks entering the water, where they are more vulnerable to predation.  The next section of beach to be covered by the team was the Summerhouse Beach where a total of five Herring Gull chicks was colour ringed.  The corpses of two dead adult Shags were noted and a further Shag nest with two large young was located.

 After the very good breeding season for gulls on Jethou in 2013, this year seems to be a little less productive with the best breeding sites around the beaches in front of the house and by the burner, with a total of 44 Herring Gull chicks being colour ringed plus one metal ringed only. Evidence of the impact of rats on gull breeding success (as well as other seabirds) on Crevichon and Grande Fauconniere is marked, with numerous burrows noted and corpses of chicks. Great Black-backed Gulls in the Southwest coast of Jethou appear to be have been successful this year, with a total of 20 being colour ringed but this was not the same case on Crevichon, where nests of this gull species appeared to be unusually scarce.

 With our survey work completed an hour early,  Bill very kindly gave us a fast ride back to Guernsey.




29 June 2014