Starlings return for winter

Thousands of starlings return to Gretna. Britain gets a huge influx of starlings from Russia and northern Europe. They come here to roost in the relative warmth. However, the species which is now listed as one of the most at-risk birds in Britain Photograph: Owen Humphreys/PA

Starlings are thought to form flocks for safety in numbers, warmth, and possibly communication. Quite why or how the birds move together so fluidly, making such specific shapes, remains a mystery Photograph: Owen Humphreys/PA

Why the birds are disappearing is also unknown, though most blame the loss of insects for the starlings to eat because of the increase in chemical use on farms since the 1970s and new grassland management techniques Photograph: Owen Humphreys/PA

Each night before they roost, starlings swoop around the skies in spectacular formations. The best time to catch this is in the evening – an hour before it gets dark Photograph: Owen Humphreys/PA

Flocks start forming around November each year, and stay together right through to spring when the birds go off - some abroad, some not - to breed Photograph: Owen Humphreys/PA

Some flocks have been estimated to contain 2 million birds – though not in the UK. Birdwatchers on Brighton Pier have estimated there are about 40,000 birds doing their aerial ballet just before dusk Photograph: Owen Humphreys/PA