Andy Trowbridge / Male Goldfinch (Carduelis carduelis) perched on flowering European bird cherry (Prunus padus). Southern Norway. May.

Andy Trowbridge / Greenfinch (Carduelis chloris) perched on flowering European bird cherry (Prunus padus). Back-lit. Southern Norway. May.

Alex Hyde / Bird Cherry (Prunus padus) blossom. Peak District National Park, Derbyshire, UK. April.

Chris Mattison / Flowering bird cherry (Prunus padus), Cumbria, UK. April.

Chris Mattison / Flowering bird cherry (Prunus padus), Cumbria, UK. April.

Colin Varndell / Bird cherry (Prunus padus) flower, Dorset, UK. May

Konrad Wothe / Bird cherry (Prunus padus) fruits on tree in rain, Bavaria, Germany. June.

John Waters / Caterpillars of the Bird-cherry ermine moth (Yponomeuta evonymella) among silk strands of a huge communal web covering host tree (Prunus padus) and protecting the many pupae in their silk cocoons from...

John Waters / Caterpillar of Bird-cherry ermine moth (Yponomeuta evonymella) among silk strands of a huge communal web that covering the host tree (Prunus padus) and protecting the many pupae in silk cocoons from a...

John Waters / Communal web of Bird-cherry ermine moth (Yponomeuta evonymella) covering defoliated host tree, Bird Cherry (Prunus padus) while protecting caterpillars and pupae from predators, Bristol, UK, June.

John Waters / Detail of communal web of Bird-cherry ermine moth (Yponomeuta evonymella) which is covering host tree, Bird cherry (Prunus padus) and protecting caterpillars and pupae from predators, Bristol, UK, Jun...

John Waters / Communal web of Bird-cherry ermine moths (Yponomeuta evonymella) covering its host tree, Bird cherry (Prunus padus) and protecting caterpillars and pupae from predators, Bristol, UK, June.