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.

Simon Colmer / Goat willow (Salix caprea) twig and opening buds in winter, UK

Simon Colmer / Goat willow (Salix caprea) opening buds in spring, UK

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

David Woodfall / Purple emperor butterfly (Apatura iris) male on Goat willow (Salix caprea). Knepp Wildland Project, formerly intensive farmland now turned to conservation and sustainable farming. Horsham, West Sussex...