If you read Sea Room, you will fall in love with puffins, utterly endearing, quirky birds.  Here Nicolson describes their appearance after the annual return to their burrows.  They never change burrow and the spring cleaning is done by both parties in the lifelong monogamous couples.  ‘Squaddies at Passchendaele’ conveys muddiness in extremis.

‘The birds are soon spattered and slick with mud, especially if it has been rainy and the burrow is leaky.  They emerge from their sodden homes like squaddies at Passchendaele.’

See also the quote rich mosaic review of this magnificent, entrancing book: a love letter to islands and a paean to the sea. 

Source: Adam Nicolson, Sea Room: An Island Life (London: Harper Collins, 2013 (2002)), p. 179-80