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Diary of a WWT Warden

Barnacle Geese at Caerlaverock WWT (© Brian Morrel)

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.

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

Me with a satellite tagged Barnacle Goose

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.

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.

Whooper Swans during feeding session (© Brian Morrel)

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.

Red-breasted Goose (© WWT Caerlaverock)

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.

Brambling on feeders at Caerlaverock WWT (© Mike Youdale)

Mike Youdale
Feb 2012