Sven Zacek / Horned grebe (Podiceps auritus) with fish in beak. Harjumaa, Northern Estonia. July.

Sven Zacek / Horned grebe (Podiceps auritus) shaking itself dry after diving. Harjumaa, Northern Estonia. July.

Paul Hobson / Slavonian grebe (Podiceps auritus) on water in breeding plumage, Iceland. June

Paul Hobson / Slavonian grebe (Podiceps auritus) on water in breeding plumage, Iceland. June

Paul Hobson / Slavonian grebe, Podiceps auritus, breeding plumage, Iceland

Roger Powell / Slavonian / Horned grebe (Podiceps auritus) adopting threatening pose to ward off an intruder into his breeding territory. Kolvik, Porsanger, Finmark, Norway

Roger Powell / Slavonian / Horned Grebe (Podiceps auritus) male escaping by walking across the iced surface of the lake after being driven off by the dominant male holding territory. It is extremely rare for grebes...

Roger Powell / Slavonian / Horned Grebe (Podiceps auritus) male escaping by walking across the iced surface of the lake after being driven off by the dominant male holding territory. It is extremely rare for grebes...

Roger Powell / Slavonian / Horned Grebe (Podiceps auritus) male escaping by walking across the iced surface of the lake after being driven off by the dominant male holding territory. It is extremely rare for grebes...

Roger Powell / Slavonian / Horned Grebe (Podiceps auritus) male calling excitedly while standing on the ice and looking down anxiously for signs of the dominant territorial male which has driven it to escape onto th...

Roger Powell / Slavonian / Horned Grebe (Podiceps auritus) swimming near icy edge of lake behind it. Kolvik, Porsanger, Finmark, Norway

Roger Powell / Slavonian / Horned Grebe (Podiceps auritus) swimming near nest. Kolvik, Porsanger, Finmark, Norway