Three nocturnal Bewick’s swan portraits, looking out across the Rushy Pen in early December.

Various species are audible in the background, including greylag and Canada geese, coots, moorhens, pintails and mallards.

I was surprised at how active the swans were throughout the night as families competed for territories on the water, and fascinated by their various call types which included (amongst others) isolated, iterative statements and phrases; gradual, collective displays, building towards a climax with an immediate transition to relative calm; and prolonged periods of subdued contact vocalisation amongst families.

Mixed into this busy soundscape were frequent, powerful wing splashes and bubbling water as birds stirred the lakebed in search of food.

All of these sounds are under serious threat.

The swans’ 3500km winter migration from the Russian Tundra to the UK is fraught with danger. Current and future threats include habitat loss, various forms of pollution, eutrophication, climate change, oil and gas exploration, power line/wind turbine collision, and illegal shooting (around one third of all swans examined in the UK have shot in their bodies, and many also ingest spent lead shot when feeding on agricultural land). Their population has plummeted in recent years from just over 29,000 (1995) to around 18,000 (2010).

Miraculously, many are still able to reach their winter home. You can help them by becoming a WWT member, which will directly support crucial conservation work towards protecting Bewick's swans and other wetland species and habitats around the world.

Find out more and track individual birds as they migrate via the Flight of the Swans website.