There’s only a light frost but the cold is seeping through the soles of my boots and into my toes. It’s early, to the east the horizon is a pale blue tinged with orange. The rest of the sky is black, studded with stars.

The air is still. The memory of my morning soundscape; the extra early alarm call, the humming fridge and the click of the toaster releasing its load has evaporated. The stillness is punctuated by the distant honking of pink-footed geese. They are getting closer but it’s a while before I spot their distinctive v-formation in the gradually lightening sky.

First one flock then another appears. As the orange glow of the rising sun intensifies, the world is wakening. A small group of teal seem to appear from nowhere, dark silhouettes skimming low then disappearing. A curlew calls.

My soundscape is now natural. In this age of the machine it’s unusual to not hear anything mechanical or man-made. It’s utterly absorbing, except for one thing that’s nagging at me; the chill in my feet.

The pink-footed geese have arrived on our coast to spend the winter here because it’s milder than in their breeding grounds in central Iceland and the eastern part of Greenland. Their migration is perhaps the most remarkable adaptation to surviving the cold but they also have dense layers of insulating feathers and fat reserves – the avian equivalent of thermal underwear. Yet they don’t have socks and boots. Why don’t their feet freeze?

This is the science bit. Geese and many other birds have a counter-current heat exchange in their legs. As warm blood from the body flows down the legs, it passes close to the cold blood returning from the feet and going back into the body. The heat is transferred; making the cold blood going back to the body warmer, and the warm blood going into the feet colder. This means their feet are always cool but not freezing and that they don’t lose vital body heat.

I wish I could say the same for my feet. As the geese head out in search of food after their night time roosts on this coastal nature reserve, I’m thinking of food too. A second breakfast and a warming mug of hot chocolate in the visitor centre.