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Situated on the north shore of the Solway Firth, a few miles south of Dumfries
in south west Scotland. The 726ha reserve is comprised of both grazed and
ungrazed merse (saltmarsh), improved grasslands for wintering geese and other
habitats including wet grassland, unimproved grasslands, hedgerows and shallow
pools and scrapes.
The part of the WWT reserve (243ha) is also part of the wider Caerlaverock
National Nature Reserve and the WWT reserve includes areas which are
designated; The Inner Solway Flats and Marshes SSSI is also a SPA, SAC and
Ramsar site. Caerlaverock is famous as a wintering ground for thousands of
Barnacle Geese which occur in internationally important numbers – at times
up to 30,000 birds may be present on the reserve.
The geese are joined by internationally important numbers of wintering
Whooper Swan which roost adjacent to the main centre buildings. Breeding
birds are also important at Caerlaverock and include Oystercatcher,
Lapwing, Redshank, Curlew, Shelduck and Skylark.
The site supports some of the most northerly natterjack toads in Britain a
Biodiversity Action Plan species. Following a recent significant decline at
the site we hope with careful management the species, which has also suffered
nationally over the longer-term can be retained and once again thrive here.
Sharing the requirement for temporary ponds with the toads is the tadpole
shrimp or triops. This prehistoric looking creature is found at only one other
location in the UK. |
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Today over 35,000 Svalbard Barnacle Geese winter on the Solway Firth,
with thousands feeding at WWT's Caerlaverock Wetland Centre. Their story is
one of an incredible recovery, since the dark days of the late 1940s, when no
more than 300 remained.
Establishing WWT Caerlaverock in 1970 (Our reserve was established in 1970 and
opened to the public in 1971) was instrumental in improving the fortunes of
these geese as it provides an undisturbed refuge after their long migration
from arctic Svalbard. The pasture and saltmarsh management carried out over
the summer by the reserve staff creates ideal feeding conditions for the geese
and the ongoing study of this species migration to and from Svalbard have
revealed previously unknown details of the birds’ lives.
Using satellite transmitters, attached as backpacks to selected larger male
birds using elasticised harnesses, we have uncovered the mystery of where the
geese ‘disappear’ to for a two-week period on their northward spring
migration, and identified the important pre-breeding sites they use after
leaving Norway. We also charted the lethal effect of a strong Atlantic storm
on two of the geese, witnessing one bird struggle with gale force winds for
six days before reaching his destination and have been able to calculate the
typical amount of energy or fat a goose needs to make the epic journey from
the Solway to Svalbard.
Being able to monitor the timing of migration so accurately, and the speeds
and heights at which the geese travel over land and sea has helped WWT assess
the potential threat of wind farm developments both onshore and offshore along
the Scottish and Norwegian coasts. |
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The tadpole shrimp (Triops cancriformis) has existed for over 200 million
years but only a single population – in a single pond - was known to remain in
the UK until its discovery at the WWT Caerlaverock reserve in 2004. The
tadpole shrimp is a freshwater crustacean that lives in wetland pools that
regularly dry out. It is wonderfully adapted to exploiting these temporary
environments. Its eggs can stay dormant in the mud for decades waiting for the
next wet period, whereupon it can hatch, mature and lay eggs within a few
weeks. On the other hand, it is a hopeless competitor with other species, and
a free meal for amphibians, fish and birds, so it is completely unable to
survive in permanent pools with their normal complement of wildlife.
It was once more widespread in the UK and its decline is likely to be linked
to the loss of the temporary wetlands that it needs to survive – very similar
to the habitat favoured for spawning by natterjack toads, another species
clinging on at Caerlaverock. Even more than permanent ponds, temporary pools
suffer neglect and destruction: they simply don’t look important – even to
conservationists. Since the discovery of Triops at Caerlaverock, WWT in
collaboration with partners such as Glasgow University have continued
surveying the network of temporary pools that form on the reserve (also a
necessary part of monitoring natterjack toad activity). Several more
populations have been found on the reserve which is an excellent result as
this means the species is less threatened in this area than originally
thought.
Under license, we hatched Triops eggs in aquaria at Caerlaverock, allowing us
to study them and giving visitors to the centre an opportunity to see one of
the UK’s rarest creatures. Going on records of Triops’ historic distribution,
field workers are starting to expand their search across the UK as part of a
new and exciting three year project, in partnership with WildCru and funded by
the Esmée Fairburn Foundation. Hopefully we will discover a bit more about
what makes this species tick and whether the seemingly rare tadpole shrimp has
actually been living alongside us in greater numbers than previously thought,
hidden from view by its tendency to flit in and out of existence. |
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This winter, if that’s what you choose to call it, has been very unseasonal
with mild conditions in comparison to the recent year (2010/11 temps -18), and
also a very wet winter, with December being the wettest on record here at
Caerlaverock. The whole year has been very wet (second wettest year on record)
leading to all of the fields completely saturated. Given these conditions
there have been so much natural food around the birds have not come in, in as
big a numbers as usual. I will rewind a little to the end of autumn before the
Whooper Swans, Barnacle Geese and wintering wildfowl turned up. Given the wet
year, come harvest time all the local farmers tried to make the most of a
break in the weather and harvest their crop however, during this time the
rains came back down and the farmers rushed to get the crop in. During this
rush a lot of grain was spilt in all the stubble fields and this combined with
the rain knocking grain off the crop, the fields were therefore completely
laden with excess feed. When the first Whooper Swans arrived back it didn’t
take them long to realise this and all the swans would be feeding in all the
local stubble and only turning up to roost on the reserve. To try and counter
this we placed tons of grain on the back of the Folly Pond so that when the
Whooper Swans woke up they didn’t head straight off to the grain fields. Sadly
though we couldn’t do this every day so the typical swan feeds mainly
consisted of Wigeon and Mallards. As the winter continued to present day a lot
of swans still remain in the local agriculture fields around the areas, using
old potato crops, turnips, stubble, and grass fields. The swans are now
however coming in for the feeds on a daily basis and you could typically
expect to see around 150 Whooper Swans in for the swan’s feeds which occur at
11am and 2pm. We do also lead guided walks after each swan feed led by one of
our wardens or our learning manager.
Our Barnacle Geese came in relatively late this year and still to this day not
all the birds have actually turned up on the reserve. The highest count of
this winter is 14,000 but on a typical day you could expect to see between
5,000 - 9,000 birds feeding on the grass fields on the reserve. Over this
winter period we have also had the return of the adult Ross’s Goose which we
believe has followed the Barnacle Geese north on their migration and also on
the same day we also found a Lesser Canada Goose of the race taverneri . This
bird was later seen in the end of January with a large flock of Barnacle Geese
just off the reserve, and the Ross’s Goose was located for the second year in
Rockcliffe Marshes, Cumbria. We also had good numbers of Eurasian
White-fronted Geese arrive at Caerlaverock over the winter. This is unusual
for here as we tend to find the Greenland race a more common visitor. In
January a Red-breasted Goose was found with the Barnacle Geese and remained at
Caerlaverock on and off for a week, but there were no further sightings of
this bird in February.
We have held some fantastic dawn flights over the winter, this is where we
lead a group out onto the saltmarsh in the early hours of the morning to watch
all the geese lift of the roost and head inland to start feeding. Luckily we
have one more dawn flight left this winter and this will be happening on 11th
March, meeting here at WWT Caerlaverock at 6am. This day is also a big event
called Geese Galore, which doesn’t only have the dawn flight but also two
guided walks, an illustrated at 3:30pm and also a goose bus which travels
around the local area seeing as many species of geese as possible.
Wintering wildfowl numbers have remained constant this winter with good
numbers of Teal (1,200) and Wigeon (1,500) in with the Teal we have had two
American Green-winged Teal. We also have good numbers of Shelduck on the
saltmarsh with counts of up to 1,200 on high tides. Greater Scaup also have
been recorded in good numbers off the saltmarsh with the peak count at around
1,600 but numbers of Shelduck and Scaup have started to drop away over the
last month. Gadwall numbers have remained at 13 individuals, all confined to
the Teal Pond, bar a single adult which is on the Whooper Pond and was a
ringed as a juvenile 5 years ago at Caerlaverock.
Wader numbers haven’t been as high as in recent winters with max counts of
Dunlin and Knot at between 5,000 and 7,500 and Oystercatcher numbers have been
at max around 5,000. Good numbers of Curlew, Golden Plover, Lapwing, Snipe and
Black-tailed Godwit have been present throughout the winter however, numbers
are starting to drop down again now as they move inland to their breeding
grounds.
Passerine numbers have been low in terms of counts of Reed Bunting,
Yellowhammer and Brambling. The maximum counts of two Brambling were observed
in the car park feeder and a single male has been present on and off all
winter on the feeding stations. Yellowhammers were very late to arrive into
Caerlaverock this winter. Last winter the harsh conditions enabled us to get
maximum counts of 120 but currently this winter counts have rarely exceeded 30
individuals. Reed Buntings numbers have also followed the same trend with
numbers around half of what we saw last year. |
