There's a chorus of chatter drifting towards us from the horizon, where far over the soggy plains of merse it sounds like an excited crowd engaged in happy discussion. I peer through my binoculars and watch as the geese, huddled in a tight cluster of perhaps 50-strong, gobble and cackle away, unaware that they're being watched. I wonder if they're feeling homesick, these geese, for they are not native to the Solway Firth in Scotland, where I am birdwatching at the WWT (Wildfowl and Wetlands Trust) Caerlaverock. Instead, they are decorative black-and-grey Barnacle geese from Svalbard in Norway, some 35,000 of whom travel 2,000 miles to get here each winter and enjoy the slightly milder climes.

This certainly beats my previous exploits at birdwatching, which have usually involved sitting in a hide, bored and freezing, waiting and waiting and waiting to see something, anything... WWT Caerlaverock is impressive. Set in an estuarian landscape on the Solway Firth in southern Scotland, it faces the Lakeland fells and is just up the coast from Caerlaverock Castle, a moated triangular medieval structure juxtaposed with a 17th-century manor. The wetlands comprises comfortable modern hides and lookout towers, and promises plenty of exciting sightings.

Having enjoyed watching the Barnacle geese from afar - our guide tells us they are shy creatures, and if you look directly at them they will fly off - we move on to the Whooper pond, where a wild swan feed is about to take place. I've never seen anything like it - the pond is a riot of whooper swans from Iceland, Canada geese, teals, tufted ducks, moorhens, mallards and widgeons - and, so I am told, we may even see egrets, otters, the extremely rare American widgeon and an elusive hen harrier. It is delightful watching the behaviour of the birds - the whoopers graceful and reserved, the tufted ducks dancing and diving, and the mallards charging for the fodder.

The guide tells us that although the birds arrive every day for their feed, they are wild, and any wrong move will scare them away. To end our visit, we climb the Farmhouse lookout tower and gaze across the landscape: the chattery chorus of the birds chimes across the perfectly flat wetlands towards the sea. A cluster of Barnacle geese flies overhead - it's a wonder they have the energy, I think, as I imagine them on their long, long journey to arrive here.

Find out more

WWT Caerlaverock

You can also read the blog I wrote about Caerlaverock's Barnacle geese for National Geographic Traveller here