Whilst feeding, this sociable bird forms dense flocks and may occasionally mix with redshanks (Tringa totanus) (6). They wade in water or probe the mud with their bills for food (8). During winter they feed mainly on worms and bivalve molluscs. When the tide is in, black-tailed godwits fly to roost on damp pastures (6). Black-tailed godwits meet in Iceland from mid-May to mid-June to breed, and in an amazing act of fidelity and timing, faithful pairs meet after over-wintering up to 600 miles apart. Arriving within three days of each other, pairs mate, breed and incubate their eggs together. The male remains with the hatchlings for a short time after the female has left to migrate back to her winter home. At the point the male leaves, he is unaware of the location of his partner, and so migrates elsewhere. This monogamous lifestyle can continue for up to 25 years and is only broken if the male and female fail to arrive within the same three days. There is, as yet, no understanding of how the pairs time their migrations with such accuracy. During the breeding season, black-tailed godwits become fairly noisy. A display flight is performed during which a loud nasal song is produced (2). The nest is built on the ground, and three or four eggs are produced. These are incubated for up to 24 days, and the young godwits will have fledged after a further 20 days (3). Whilst on the nest, black-tailed godwits tend to 'sit tight' when threatened, which earned the species the alternative common name of scammel, an old name meaning limpet (9).