Steve Knell / Long-tailed tit (Aegithalos caudatus rosaceus) adult perched on lichen covered twig, Lancashire, England, UK, March.

Steve Knell / Great spotted woodpecker (Dendrocopos major) adult male on snow covered branch in winter, Dumfries and Galloway, Scotland, January

Steve Knell / Great spotted woodpecker (Dendrocopos major) adult male on snow covered branch in winter, Dumfries and Galloway, Scotland, January

Steve Knell / Red squirrel (Sciurus vulgaris) adult in deep snow, Dumfries, Scotland, UK, January.

Steve Knell / Red squirrel (Sciurus vulgaris) adult feeding in deep snow, Dumfries, Scotland, UK, January.

Steve Knell / Jay (Garrulus glandarius) perched on freshly covered snow,feeding on hidden food store, Dumfries and Galloway, Scotland, January.

Steve Knell / Jay (Garrulus glandarius) perched on freshly covered snow,feeding on hidden food store, Dumfries and Galloway, Scotland, January.

Alex Mustard / A portrait of a nudibranch (Eubranchus tricolor) on the seabed of a Scottish loch. Loch Carron, Ross and Comarty, Scotland, Great Britain. North East Atlantic Ocean.

Alex Mustard / Aeolid nudibranch (Flabellina pedata) feeding on its prey of hydroids. This species cannot only eat the stinging hydroids without getting stung, but the stinging nematocysts of the hydoid pass through...