• Sun. Dec 3rd, 2023


The Pet encyclopedia

St Margarets Island and Caldey Island


We have obviously finished the counts of the seabirds on the cliffs and
islands while the seabirds were sitting on eggs but we are miles off collating
the seabird counts from the sea and the cliff photographs!  We will let you know when we have adding
everything up.

The seabird breeding season is clearly
late on Caldey and St Margarets island this year. 

Its the most synchronous season in years, probably to do with the cold wet
weather in March which stopped everything doing anything for a time. Its very
different to most years in the last decade.


On Thursday last week we ringed 99 Cormorant chicks in the largest sub-colony
of Cormorants on the south coast of  St Margarets island.


Most of the chicks were about half grown and so are two to three weeks
behind recent years. 

There were a few large chicks which were not approachable and a few nests
with tiny newly hatched chicks, no clutches of eggs.



The great black-backed gulls (GBB) seem to have also had a good year, although
the dry trampled vegetation towards the edges of the island helped to find the
big chicks.


We ringed 26. We found very few in the thicker sea beet inland maybe the
clouds of pale yellow pollen obscured our vision!!

We found a decapitated grey squirrel in one of the GBB nests – perhaps a
road casualty scavenged by the GBB’s. 

On another note the Kittiwakes all seemed to be incubating whereas by now
they would traditionally have small chicks so maybe also affected by the poor
March weather.

It sounds like some Kittiwakes on Skomer may have chosen not to breed this
year so we need to get another look at the St Margaret’s Island birds in the
next couple of weeks.


Today we visited Caldey again to ring a sample of Herring Gull chicks  and between two of the sub colonies managed
to find 156 well grown chicks, a few almost ready to fledge but most about half
grown.  More surprising was the number of
dead chicks especially around Sandtop where at least 100 were found and at both
sites we recorded no regurgitates so our conjecture is that they are
starving.  In most years we have seen a
lot of worms regurgitated and we wonder if the dry conditions of recent weeks
have meant the adults are finding it difficult to forage.

The Caldey Herring Gull colony count this year was 1,620 pairs which was
down slightly on 2022 and compares miserably with 1976 when over 3,700 were
breeding there.  All the other seabird
numbers were very similar to 2022.  Steve
recalls over 400 pairs of guls nesting between Tenby and Saundersfoot with over
100 on St Catherines Island, today there are less than 20 and just 3 pairs
respectively although there may be a few more on the rooftops of Tenby now.


Anna & Steve Sutcliffe  and the Pembrokeshire
Ringing Group