Terry Whittaker / Man sorting seabird eggs, including those of Common guillemots (Uria aalge) into egg boxes, Skoruvikurbjarg cliffs, Langanes Peninsula, Iceland, May.

Florian Möllers / Mallard (Anas platyrhynchos), female nesting in window box of a 4th floor flat, Berlin, Germany, June

Ernie Janes / Collecting free-range organic Chicken eggs (Gallus gallus domesticus) UK, September 2005

David Tipling / Great tit (Parus major) clutch of eggs in nest in nest box, garden Norfolk, England, UK, May.

Terry Whittaker / Two men on cliff top with Common guillemot / murre (Uria aalge) eggs collected from cliff face. Skoruvikurbjarg cliffs, Langanes Peninsula, Iceland. May 2018.

Terry Whittaker / Common murre / guillemot (Uria aalge) and Black-legged kittiwake (Rissa tridactyla) eggs in box and egg boxes. Collected from Skoruvikurbjarg cliffs, Langanes Peninsula, Iceland. May 2018.

Terry Whittaker / Seabird eggs including those of Common murre/ guillemot (Uria aalge) in fridge. Collected from Skoruvikurbjarg cliffs, Langanes Peninsula, Iceland. May 2018.

Terry Whittaker / Common murre / guillemot (Uria aalge) eggs in box. Foraged from Skoruvikurbjarg cliffs, Langanes Peninsula, Iceland. May 2018.

Terry Whittaker / Men sorting seabird eggs, including those of Common guillemots (Uria aalge) into egg boxes, Skoruvikurbjarg cliffs, Langanes Peninsula, Iceland, May.

Terry Whittaker / Box of harvested seabird eggs, including those of Common guillemots (Uria aalge), Skoruvikurbjarg cliffs, Langanes Peninsula, Iceland, May.

Terry Whittaker / Man gathering harvested seabird eggs, including those of Common guillemots (Uria aalge) into a box, Skoruvikurbjarg cliffs, Langanes Peninsula, Iceland, May.

Ashley Cooper / Box of free range eggs of varying colour from chickens of different breeds.