Marie Read / American Robin (Turdus migratorius), feeding on winterberry (Ilex) fruits in winter, New York, USA, December.

Ashley Cooper / Needle ice on Holly leaves (Ilex europaeus) in a woodland in Ambleside Cumbria UK. December 2008

Lucas Bustamante / Two Limon glass frogs (Sachatamia ilex) sitting on plant, one above the other, Canande, Esmeraldas.

Nick Garbutt / Montane Glass Frog (Centrolenella ilex) inside curled leaf. Mid-altitude rainforest, Bosque de Paz, Pacific slope, Costa Rica, Central America.

Andres M. Dominguez / Holm oak tree (Quercus ilex) in snowfall, Sierra de Grazalema Natural Park, southern Spain, January.

Stephen Dalton / Close-up of holly leaf (Ilex aquifolium).

Juan Carlos Munoz / Iberian black pig in oak woodland, Sierra de Aracena Natural Park, Huelva, Andalucia, Spain, Europe. Breed used to produce Iberico ham / Jamon Iberico

Juan Carlos Munoz / Iberian black pig foraging in oak woodland, Sierra de Aracena Natural Park, Huelva, Andalucia, Spain, Europe. Breed used to produce Iberico ham / Jamon Iberico

Marie Read / Male Eastern bluebird (Sialia sialis) feeding on winterberry (Ilex sp) fruit, New York, USA, January

Marie Read / Male American robin (Turdus migratorius) feeding on Winterberry (Ilex sp) New York, USA, January

B&S Draker / Northern Cardinal (Cardinalis cardinalis) male eating Possum Haw Holly (Ilex decidua) berries. Bandera, Hill Country, Texas, USA.

Rolf Nussbaumer / Chipping Sparrow (Spizella passerina) adult on ice covered Possum Haw Holly (Ilex decidua) berries. New Braunfels, San Antonio, Hill Country, Central Texas, USA, January.