Andres M. Dominguez / Bacteria (Lepthotryx discophora) causing iridescent patterns and White willow tree leaf (Salix alba) in river, Sierra de Grazalema Natural Park, southern Spain, November.

Markus Varesvuo / Willow grouse (Lagopus lagopus) Kiilopaa, Inari, Finland, January.

Markus Varesvuo / Willow Grouse (Lagopus lagopus) in flight over snowy landscape, Utsjoki, Finland April

Guy Edwardes / 2020VISION / View south with willow trees over Walton Moor on the Somerset Levels from Walton Hill on a misty winter evening with snow on the ground, Somerset, UK, December 2010. Photographer quote: 'The temperatu...

Grzegorz Lesniewski / Riparian forest with Crack Willow (Salix fragilis), White Willow (Salix alba) and blooming Wild Cherry (Prunus avium). Bieszczady Mountains, the Carpathians, Poland, May.

Wild Wonders of Europe / della Ferrera / Flooded trees, mainly White willow (Salix alba) Livanjsko Polje (karst plateau) Bosnia and Herzegovinam May 2009

Wild Wonders of Europe / della Ferrera / White willow (Salix alba) trees in flooded area near a graveyard and a house, Northern Livanjsko Polje (karst plateau) Kazanc area, Bosnia and Herzegovina, May 2009

Wild Wonders of Europe / della Ferrera / Trees, mainly White willow (Salix alba) in flooded karst plateau, Livanjsko Polje, Bosnia and Herzegovina, May 2009

Wild Wonders of Europe / della Ferrera / Trees, mainly White willow (Salix alba) in flooded karst plateau, Livanjsko Polje, Bosnia and Herzegovina, May 2009

Nigel Cattlin / Goat willow (Salix caprea) male catkins. Kennett and Avon Canal, Berkshire, England, UK. April.

Sven Zacek / European elk (Alces alces), three standing together near frost covered Willow (Salix sp) bushes with Suur Emajogi River beyond. Alam-Pedja Nature Reserve, Tartumaa, Southern Estonia. January 2011.

Juan Carlos Munoz / Man moving bundles of cut Willow (Salix), used to make wicker products, Cuenca, Castilla-La Mancha, Spain, December.

Phil Savoie / Garden bumblebee (Bombus hortorum) visiting Goat willow (Salix caprea) male catkins, Monmouthshire, Wales, UK. March.

Phil Savoie / Garden bumblebee (Bombus hortorum) visiting Goat willow (Salix caprea) male catkins, Monmouthshire, Wales, UK. March.

Markus Varesvuo / Willow grouse (Lagopus lagopus) sheltering under snow laden tree, Inari Kiilopa Finland January

Markus Varesvuo / Willow grouse (Lagopus lagopus) feeding in snow laden tree, Inari Kiilopää Finland January

Markus Varesvuo / Willow grouse (Lagopus lagopus) extremely well camouflaged below snow laden tree, Inari Kiilopaa Finland January

Markus Varesvuo / Willow grouse (Lagopus lagopus) extremely well camouflaged below snow laden tree, Inari Kiilopaa Finland January

Markus Varesvuo / Willow grouse (Lagopus lagopus) perched on top of snow laden tree, Inari Kiilopaa Finland January

Markus Varesvuo / Willow grouse (Lagopus lagopus) extremely well camouflaged below snow laden tree, Inari Kiilopaa Finland January Highly commended in the Bird category of the Asferico Photography Competition 2017.

Andres M. Dominguez / Bacteria (Leptothryx discophora) causing iridescent sheen on water surface with White willow leaf (Salix alba). Sierra de Grazalema Natural Park, southern Spain, November.

Andres M. Dominguez / Bacteria (Leptothryx discophora) causing iridescent sheen on water surface with White willow leaf (Salix alba). Sierra de Grazalema Natural Park, southern Spain, November.

Markus Varesvuo / Willow grouse / Ptarmigan (Lagopus lagopus) sitting next to snow covered tree, Inari Kiilopaa, Finland, February.

Markus Varesvuo / Willow grouse / Ptarmigan (Lagopus lagopus) standing at foot of tree, Utsjoki, Finland, April.

MYN / Niall Benvie / Crack willow (Salix fragilis) catkins, Angus, Scotland, UK, May.

Fabrice Cahez / White willow (Salix alba) catkin, Vosges, France, April.

Nick Upton / Tom Buckley setting up an infra red trailcam on a Willow tree (Salix sp.) felled by Eurasian beavers (Castor fiber) on the banks of the River Otter, Devon, England, UK, May. Model released.

Nick Upton / Tom Buckley setting up an infra red trailcam on a Willow tree (Salix sp.) felled by Eurasian beavers (Castor fiber) on the banks of the River Otter, Devon, England, UK, May. Model released.

Nick Upton / Tom Buckley setting up an infra red trailcam on a Willow tree (Salix sp.) felled by Eurasian beavers (Castor fiber) on the banks of the River Otter, Devon, England, UK, May. Model released.

Nick Upton / Tom Buckley setting up an infra red trailcam on a Willow tree (Salix sp.) felled by Eurasian beavers (Castor fiber) on the banks of the River Otter, Devon, England, UK, May. Model released.

Nick Upton / Eurasian beaver (Castor fiber) kit feeding on Willow (Salix) leaves at night, born in the wild on the River Otter, part of a release project managed by the Devon Wildlife Trust, Devon, England, UK, Au...

Markus Varesvuo / Willow grouse (Lagopus lagopus) in tree, Kiilopaa, Inari, Finland, January.

Markus Varesvuo / Willow grouse (Lagopus lagopus) in tree near parked cars, Kiilopaa, Inari, Finland, January.

Alex Hyde / Goat / Pussy Willow (Salix caprea) male catkins against a white background. Leicestershire, UK. April.

Jean E. Roche / Treehouse in big Willow (Salix alba) tree, Bresse, France, April 2013.

Jean E. Roche / Pollarded Willow trees (Salix alba) Anse de Longepierre, Bresse, France, April.

Jean E. Roche / Pollarded Willow trees (Salix alba) Anse de Longepierre, Bresse, France, April.

Florian Möllers / White stork (Ciconia ciconia) captive, adult resting under willow tree, Vogelpark Marlow, Germany, May.

Guy Edwardes / 2020VISION / View south with pollarded willow trees over Walton Moor on the Somerset Levels from Walton Hill on a misty winter evening with snow on the ground, Somerset, UK, December 2010

Guy Edwardes / 2020VISION / View south over the Somerset Levels from Walton Hill on a misty winter evening with snow on the ground. View includes Butleigh Moor, Somerton Moor, Street Moor, Low Ham Moor, Walton Moor, Pitney Moor,...

Grzegorz Lesniewski / Riparian forest with Crack Willow (Salix fragilis), White Willow (Salix alba) and blooming Wild Cherry (Prunus avium). Bieszczady Mountains, the Carpathians, Poland, May.

Nigel Bean / White willow trees (Salix alba) covered in hoar frost, Somerset Levels, UK, December 2010

Nigel Bean / White willow trees (Salix alba) covered in hoar frost, Somerset Levels, UK, December 2010

Nigel Bean / White willow trees (Salix alba) covered in hoar frost, Somerset Levels, UK, December 2010

Nigel Bean / White willow tree (Salix alba) covered in hoar frost, Somerset Levels, UK, December 2010

Nigel Bean / White willow tree (Salix alba) covered in hoar frost, Somerset Levels, UK, December 2010

Simon Colmer / Goat willow (Salix caprea) buds in winter against white background, UK

Nick Upton / Heavily hoar-frosted Philadelphus bush and Weeping willow tree, Wiltshire garden, UK, December 2010