SCOTLAND: The Big Picture / Red Squirrel (Sciurus vulgaris) tossing away the husk from hazelnut, Cairngorms National Park, Highlands, Scotland, UK, November.

Wild Wonders of Europe / Wothe / Hazelnut weevil (Curculio nucum) portrait, Eastern Slovakia, Europe, June 2009

Kim Taylor / Hazelnut weevil (Curculio nucum) portrait, Surrey, England

Terry Andrewartha / Red squirrel with hazelnut {Sciurus carolinensis} UK

Nigel Cattlin / Hazel nuts (Corylus avellana) maturing on tree in summer. Berkshire, England, UK. July.

Heather Angel / Hazel (Corylus avellana) catkins dispersing pollen with female flower above on branch. Controlled condition.s Surrey, England, UK.

Gary K. Smith / Common redpoll (Carduelis flammea) perched on corkscrew hazel with catkins, England, UK. March.

Gary K. Smith / Siskin (Carduelis spinus) perched on corkscrew hazel with catkins, England, UK. March.

Gary K. Smith / Common redpoll (Carduelis flammea) male, perched on corkscrew hazel with catkins, England, UK. March.

Gary K. Smith / Goldfinch (Carduelis carduelis) perched on corkscrew hazel with catkins, England, UK. March.

Andy Sands / Hazel (Corylus avellana) close up image of female flower, Hertfordshire, England, UK, February, Focus Stacked

Andy Sands / Hazel (Corylus avellana) image of both Male flower - catkin and female flower, Hertfordshire, England, UK, February, Focus Stacked

Andy Sands / Hazel Trees (Corylus avellana) ancient coppice Hazel stools, with Ramsons (Allium ursinum) growing below, example of woodmanship and traditional woodland managment, Suffolk, England, UK, April

Andy Sands / Hazel tree (Corylus avellana) ancient coppice stool with Wild garlic (Allium ursinum) flowering below, traditional woodland management, Suffolk, England, UK, April

Philippe Clement / Common hazel (Corylus avellana) close up of female catkin concealed in bud with only the red styles visible against blue sky, Belgium, February

Philippe Clement / Common hazel (Corylus avellana) close up of male catkins dispersing pollen in early spring, Belgium, February

Colin Varndell / Hazel nut (Corylus avellana) cases on forest floor, broken by grey squirrel. Dorset, UK August.

Adrian Davies / Stinking hellebore (Helleborus foetidus) in hazel woodland. Surrey, England, UK. April.

Adrian Davies / Toothwort (Lathraea squamaria), parasitic on hazel (Corylus avellana) tree roots, ancient woodland indicator species. Surrey, England, UK. April.

Adrian Davies / Toothwort (Lathraea squamaria), parasitic on hazel (Corylus avellana) tree roots, ancient woodland indicator species. Surrey, England, UK. April, 2018.

Adrian Davies / Toothwort (Lathraea squamaria), parasitic on hazel (Corylus avellana) tree roots, ancient woodland indicator species. Surrey, England, UK. April.

Nick Upton / Hazel (Corylus avellana) male catkins and small female inflorescence with snow in the background, Wiltshire, UK, March.

Stephen Dalton / Hazel catkins (Corylus avellana) Sussex, England, UK, February.

Robert Thompson / Hazel catkins (Corylus avellana) and female flower, Northern Ireleand.

David Pattyn / Spotted nutcracker (Nucifraga caryocatactes) with hazelnut in forest, Crans Montana, the Alps, Wallis, Switzerland. February

David Pattyn / Spotted nutcracker (Nucifraga caryocatactes) with hazelnut, Crans Montana, the Alps, Wallis, Switzerland. February

Pal Hermansen / Spotted nutcracker (Nucifraga caryocatactes) finding cached hazelnut, Sweden, February.

Pal Hermansen / Spotted nutcracker (Nucifraga caryocatactes) finding cached hazelnut, Sweden, February.

Stephen Dalton / Hazel (Corylus avellana) catkins shedding pollen, Primroses (Primula vulgaris) in woodland setting, Rookery Wood, Sussex, England, UK, February.

Stephen Dalton / Woodland path with freshly coppiced Hazel (Corylus avellana) at edges, Rookery Wood, Sussex, England, UK, October 2016.

Stephen Dalton / Hazel (Corylus avellana) coppiced at 18 inches to prevent damage from rabbits and Muntjac deer, Rookery Wood, Sussex, England, UK, October 2016.

Dave Bevan / Male Great spotted woodpecker (Dendrocopos major) trying to open a hazelnut cached in a branch, Carmarthenshire, Wales, UK, November.

SCOTLAND: The Big Picture / Great spotted woodpecker (Dendrocopos major) feeding on a hazelnut, Cairngorms National Park, Scotland, UK, March.

Nick Upton / Male White admiral butterfly (Limenitis camilla) resting on a Hazel (Corylus avellana) leaf, opening and closing its wings, Lower Woods Gloucestershire Wildlife Trust reserve, England, UK, July.

Chris Mattison / Hazel (Corylus avellana) female flower. Monmouthshire, February

Jeroen Stel/ BIA / Eurasian Red Squirrel (Sciurus vulgaris) feeding on hazelnut, Netherlands

Nick Upton / Yellow specklebelly lichen (Pseudocyphellaria crocata) with golden soralia on a Hazel (Corylus avellana) treetrunk in ancient Atlantic woodland, Knapdale Forest, Argyll, Scotland, UK, May.

Colin Varndell / Hazel (Corylus avellana) leaf in early summer. Dorset, UK. June

SCOTLAND: The Big Picture / Red squirrel (Sciurus vulgaris) in winter coat feeding on hazelnut in forest, Cairngorms National Park, Scotland, UK, December.

Mark Hamblin / Red Squirrel (Sciurus vulgaris) feeding on hazelnut, Cairngorms National Park, Scotland, UK. December.

Lorraine Bennery / Hazelnut weevil (Curculio nucum) on a grass, La Brenne Regional Natural Park, France, May.

Chris Mattison / Limestone oak fern (Gymnocarpium robertianum) and Hazel (Corylus avellana) growing in scree in a limestone dale. Peak District, Derbyshire, UK, May.

Chris Mattison / Limestone oak fern (Gymnocarpium robertianum) and Hazel, (Corylus avellana) growing in scree in a limestone dale. Peak District, Derbyshire, UK, May.

Chris Mattison / Coppiced hazel (Corylus avellana) growing in a limestone dale. Peak District, Derbyshire.

Chris Mattison / Coppiced hazel (Corylus avellana) growing in a limestone dale. Peak District, Derbyshire, UK, May.

Loic Poidevin / Blue tit (Cyanistes caeruleus) sitting on Hazel (Corylus) with catkins, Loire Atlantique, France, January

Loic Poidevin / Great tit (Parus major) sitting on Hazel (Corylus) with catkins, Loire Atlantique, France, January

Loic Poidevin / Great tit (Parus major) sitting on Hazel (Corylus) with catkins, Loire Atlantique, France, January

Nick Turner / Coppiced Hazel stool (Corylus avellana) Ullenwood, Coberley, Gloucestershire, UK. February.

Mike Read / Common hazel (Corylus avellana) individual leaf on lightbox Ringwood Hampshire UK October

Niall Benvie / Hazel tree (Corylus avellana) spring leaves, Upper Glen Finglas, Glen Finglas, West Dumbartonshire, Scotland, July.

Nick Upton / Hazel (Corylus avellana) young male catkins, GWT Lower Woods reserve, Gloucestershire, UK, October.

Alex Hyde / Stunted yew (Taxus baccata) and Hazel (Corylus avellana) trees growing in limestone pavement gryke, Gait Barrows National Nature Reserve, Lancashire, UK. September.

Colin Varndell / Hazel leaves (Corylus avellana) in spring. Dorset, UK, May.

Pascal Pittorino / Beautiful demoiselle damselfly (Calopteryx virgo) female on a leaf of Hazel ( Corylus avellana), Lozere, Cevennes, Languedoc Roussillon, France, May

Roger Powell / Blue tit (Cyanistes caeruleus) on a Hazel (Corylus) branch with catkins. Lower Saxony, Germany. February.

Roger Powell / Blue tit (Cyanistes caeruleus) on a Hazel (Corylus) branch with catkins. Lower Saxony, Germany. February.

Roger Powell / Hawfinch (Coccothraustes coccothraustes coccothraustes) female perched on a Hazel branch (Corylus) surrounded by catkins. Lower Saxony, Germany, Febraury.

Roger Powell / European greenfinch (Chloris chloris chloris) male on branch with Hazel catkins (Corylus) Lower Saxony, Germany, February.

Roger Powell / European greenfinch (Chloris chloris chloris) male on branch with Hazel catkins (Corylus) Lower Saxony, Germany, February.

Roger Powell / Eurasian bullfinch (Pyrrhula pyrrhula) with a seed in its beak, perched on a Hazel (Corylus) branch with catkins. Lower Saxony, Germany

Russell Cooper / Common Hazel (Corylus avellana) nuts, London, July

Nick Upton / Common toothwort (Lathraea squamaria), a parasite of Hazel (Corylus), flowering in woodland, Bath and Northeast Somerset, UK, April.

Nick Upton / Common toothwort (Lathraea squamaria), a parasite of Hazel (Corylus), flowering in woodland, Bath and Northeast Somerset, UK, April.

Colin Varndell / Hazel (Corylus avellana) leaf in spring. Dorset, UK, May.

Colin Varndell / Hazel (Corylus avellana) leaves in spring, Dorset, UK. April.

Alex Hyde / Hazel female flower (Corylus avellana), Peak District National Park, Derbyshire, UK. March.

Alex Hyde / Hazel catkins (Corylus avellana), Peak District National Park, Derbyshire, UK. March.

Nick Upton / Timber in deciduous ancient woodland, managed by coppicing, with a mix of Beech (Fagus sylvatica), Silver birch (Betula pendula) and Hazel (Corylus avellana), chosen for Dormouse reintroduction, Notti...

Nick Upton / Lorna Griffiths of Nottinghamshire Wildlife Trust providing young Hazel branches (Corylus avellana) as food and cover for a Hazel dormouse (Muscardinus avellanarius) 'soft release' cage before the nes...

Ernie Janes / Hazel (Corylus avellana) catkins silhouetted in late winter at sunset, England, February.

Ernie Janes / Hazel (Corylus avellana) catkins in late winter against a setting sun, England, February.

Ernie Janes / Hazel (Corylus avellana) catkins silhouetted in late winter against a setting sun, England, February.

Colin Varndell / Hazel (Corylus avellana) nuts developing in summer. Dorset, UK, June.

Colin Varndell / Fresh hazel (Corylus avellana) leaf in spring. Dorset, UK, April.

Guy Edwardes / 2020VISION / Young Hazel (Corylus avellana) leaves in spring, with a dead leaf from the previous year, New Forest National Park, Hampshire, England, UK, April.

Michel Poinsignon / Great spotted woodpecker (Dendrocopos major) on birch tree in winter, carrying a hazelnut in beak, Lorraine, France, March

Duncan Usher / Harvest Mouse (Micromys minutus) feeding on hazelnut, Lower Saxony, Germany

Fabrice Cahez / Red squirrel (Sciurus vulgaris) on branch feeding on hazelnut, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) feeding on hazelnut, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) with hazelnut, Allier, Auvergne, France, March

Mark Taylor / Young Grey Squirrel (Sciurus carolinensis) domesticated, eating a hazelnut.

Philippe Clement / Great Spotted Woodpecker (Dendrocopos major) male with hazelnut in beak on tree trunk in forest, Belgium, July

Fabrice Cahez / Red squirrel (Sciurus vulgaris) with hazelnut in mouth, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) eating hazelnut, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) eating hazelnut, with Great tit (Parus major) in the background watching, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) climbing down tree with hazelnut, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) eating hazelnut, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) eating hazelnut, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) eating hazelnut, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) eating hazelnut, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) on tree trunk eating a hazelnut, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) running down tree with hazelnut in its mouth, Allier, Auvergne, France, March