Steve Knell / White wagtail (Motacilla alba alba) perched on rock. Iceland, May

Steve Knell / White wagtail (Motacilla alba alba) perched on rock. Iceland, May

Steve Knell / Slavonian grebe (Podiceps auritus) breeding pair in summer plumage. Iceland. May

Steve Knell / Slavonian grebe (Podiceps auritus) portrait on water in summer plumage. Iceland. May

Steve Knell / Red-breasted merganser (Mergus serrator) pair silhouetted at sunset, on lake Myvatn, Iceland, May

Steve Knell / Great Northern Diver (Gavia immer) on water, in summer plumage. Iceland, June

Steve Knell / Great Skua (Stercorarius skua) sitting on grass with beak open in rain. Iceland, May

Steve Knell / Gadwall (Anas strepera) portrait of female on water, with reflections, Iceland, May

Steve Knell / Gadwall (Anas strepera) portrait of drake on water. Iceland, May

Steve Knell / Blackbird (Turdus merula) female on old post, Gloucester, England. February

Steve Knell / Black-tailed godwit (Limosa limosa) silhouetted at sunset. Iceland, May

Steve Knell / Black-tailed godwit (Limosa limosa) silhouetted at sunset. Iceland, May