It was a gorgeous day for our first
seabird monitoring trip to Jethou on the early date on Thursday 2nd
June. This was about a week earlier than we would normally go to the
island to ring and monitor the nesting European Shags. However, our
visit to some of The Humps north of Herm on 11 May had shown us what an
early season it is this year for this species!
With the kind permission of Dr Peter Ogden the five members of the
Guernsey Seabird Team for this visit (Jamie Hooper, Chris Mourant,
Chris & Mandy Dee and Paul Veron) caught the 0800 work boat across
to the island. We arrived shortly after high tide, so we were able to
look for a few colour ringed gulls around the beaches near the landing
before making a clockwise circuit of the island, ringing shag chicks in
nests on the low cliffs.
Paul was thrilled to get some early success with monitoring colour
ringed gulls. With some effort through the day just over 30 colour
ringed Herring Gulls and one Lesser Black-backed Gull were recorded,
which is a fantastic contribution to the gull studies, as it is
particularly valuable to know where these gulls are nesting. All the
Herring Gulls had been ringed either at Chouet landfill or in our
garden at Ty Coed, Vale Marais, while the single cr Lesser Black-backed
Gull had been ringed at Chouet in May 2010.
It soon became apparent that the Shag have had an incredibly
early breeding season. As we worked our way around the island we could
see fledged young on the rocky shoreline, and there were also juvenile
birds in the sea. Notwithstanding this we managed to ring 35 well grown
chicks in their nests. The very early fledging made it very hard this
year to assess breeding success, but we all agreed that most of the
empty nests were well trampelled with lots of guano, so the
probablity is that most of the chicks from these nests had already
successfully fledged. We estimated that productivity in 2011 has been
moderate to good. Not a bumper year, but certainly very satisfactory.
Although the Shags had nested very eary - in fact the earliest I have
ever seen on my near annual visits since 1980, the gulls appeared to be
pretty much on time. Many of the Herring Gull nests had very small
chicks, and the Great Black-backed Gulls were either still on full
clutches of three eggs, or very small young. The most advanced GBBG
young we found were just under half-grown. Lesser Black-backed Gulls
were typically scarce and scattered, but were on eggs or tiny young.
Our overall impression of gull numbers was slightly down on "normal".
This is consistent with what we have seen elsewhere in the Bailiwick
for Herring Gull this year. Why this should be is a mystery, as
there is no shortage of food (natural and man-made).
A large male Grey Seal was seen close inshore off the western end of
the island. The island itself is not surprisingly very dry around the
coastal edge - and especially on Grande Fauconniere and Crevichon.
After completing the circuit of the island we enjoyed a cool drink back
at the landing, where a late migrant Hobby flew over. We then set off
to cross to Grande Fauconniere. Most of the nests on this islet were
already empty, with the young having fledged. However, we did manage to
ring 21 large youngsters, along with four Great Black-backed Gulls
(three of which were large enough to take colour rings).
To complete our work we visited Crevichon on low tide, where we ringed
another 32 Shag, along with another couple of Great Black-backed Gulls.
The Little Egret colony looked very healthy with a minimum of 12 nests.
However, because several of the youngsters were large and mobile we
only ringed two chicks before retreating. It was disappointing to see
that at least four of the chicks had been predated while half
Back at the landing we watched the Herring Gulls mob a Peregrine,
before catching the 1600 boat back to Guernsey,.
It had been a very valuable visit both from the point of view of
monitoring the Shag breeding season, and also in terms of recording
colour ringed gulls for the long-term study. 96 seabirds were ringed:-
88 Shag, six Great Black-backed Gulls and two Little Egrets. Our thanks
again to Dr Ogden and the staff of Jethou who made this visit possible.