Alex Hyde / Peacock butterfly (Inachis io) feeding on Goat Willow catkins (Salix caprea), an important food source for pollinators in early spring. Peak District National Park, UK. April.

Bernard Castelein / Goat willow (Salix caprea) in mist at dawn, full moon in sky. Klein Schietveld, Brasschaat, Belgium. August 2019.

Bernard Castelein / Goat willow (Salix caprea) tree in mist at dawn. Klein Schietveld, Brasschaat, Belgium. August 2019.

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

Heather Angel / Common bee fly (Bombylius major) nectaring on Goat willow (Salix caprea) catkin. Surrey, England, UK. March.

Heather Angel / Goat willow (Salix caprea) female catkin in UV light, fine hairs and nectar fluroescing. Surrey, England, UK. Focus stacked.

Mike Read / Goat willow (Salix caprea) catkins and new leaves. Blashford Lakes Nature Reserve, Hampshire and Isle of Wight Wildlife Trust Reserve, Ellingham, Ringwood, Hampshire, England, UK. April.

Andy Sands / Goat wIllow (Salix caprea) Young male catkins often known as pussy willow, Hertfordshire, England, UK, April

Erlend Haarberg / Great spotted woodpecker (Dendrocopus major) on a Goat willow (Salix caprea) Klaebu, Norway, September

Adrian Davies / Goat willow (Salix caprea) catkin shedding feathery seeds. Surrey, England, UK. May.

Adrian Davies / Goat willow (Salix caprea) catkin shedding feathery seed. Surrey, England, UK. May

Matthew Maran / Goat willow (Salix caprea) felled by a Eurasian beaver (Castor fiber) with teeth marks The riverside tree will resprout with new shoots supplying a source of food for the beavers for years to come. De...