Marie Read / Lewis's Woodpecker (Melanerpes lewis) outside its nest hole in burned Jeffrey Pine (Pinus jeffreyi), with beakful of insects to feed its young, Mono Lake Basin, California, USA. (Digitally retouched...

Dave Bevan / Blackbird (Turdus merula) male on lawn with beakful of worms, UK

Nick Upton / Jackdaw (Corvus monedula) landing on nest box with beakful of animal hair to line nest with, Wiltshire, UK, March.

Nick Upton / Coot (Fulica atra) swimming to its nest with beakful of nest material as its mate incubates eggs, Gloucestershire, UK, June.

Nick Upton / Coot (Fulica atra) swimming to its nest with beakful of nest material as its mate incubates eggs, Gloucestershire, UK, June.

Nick Upton / Reed warbler (Acrocephalus scirpaceus) perched with beakful of Common reed (Phragmites australis) flowers to line nest with, Gloucestershire, UK, June.

Tim Laman / Helmeted hornbill (Rhinoplax vigil) male, passing beakful of figs to his mate inside nest cavity in tree hole, Budo Su-ngai National Park, Thailand.

Juan Carlos Munoz / Female Red rock thrush (Monticola saxatilis) with a beakful of grubs, Castilla y Leon, Spain. July.

Nick Upton / Jackdaw (Corvus monedula) emerging from a nest box beside its mate with a beakful of old moss and leaves it is clearing out from the nest the pair built the year before, Wiltshire, UK, March.

Nick Upton / Jackdaw (Corvus monedula) emerging from a nest box with a beakful of old moss it is clearing out before rebuilding, watched by its mate, Wiltshire, UK, March.

Nick Upton / Common starling (Sturnus vulgaris) emerging from its nest site under stone roof tiles on an old cottage with a beakful of droppings from its chicks to keep the nest clean, Lacock, Wiltshire, UK, May.

Robert Thompson / Atlantic puffin (Fratercula arctica) with beakful of fish, Saltee Islands, County Wexford, Republic of Ireland.