Gerrit Vyn / Willow Ptarmigan (Lagopus lagopus) male standing on snow covered ground, vocalising in spring courtship. Males retain the white body plumage of winter plumage and molt the head and neck feathers to th...

Rolf Nussbaumer / Chestnut-Breasted Coronet hummingbird (Boissonneaua matthewsii) adult feeding from fuchsia flower, Papallacta, Ecuador, Andes, South America, January

Nigel Cattlin / Russeting to apple fruit and bronzing to leaves by fruit tree red spider mite (Panonychus ulmi)

Lucas Bustamante / Russet-backed oropendola (Psarocolius angustifrons) building a nest. Tambopata National Reserve, Madre de Dios, Peru.

Nick Garbutt / Russet-backed oropendola (Psarocolius angustifrons), pair constructing nest. Manu Biosphere Reserve, Peru.

Magnus Lundgren / Wild Wonders of China / Fulvous forest skimmer, or Russet percher dragonfly (Neurothemis fulvia) female, Sai Kung, Hong Kong, China.

Alan Williams / Apple (Malus domestica) blossom variety 'Egremont Russet' in orchard, Cheshire, UK, May

Alan Williams / Apple (Malus domestica) blossom variety 'Egremont Russet' in orchard, Cheshire, UK, May

Roland Seitre / Moustached monkey (Cercopithecus erythrotis) portrait whilst feeding, captive, occurs in Cameroon, Equatorial Guinea, and Nigeria.

Konrad Wothe / Russet-backed oropendola (Psarocolius angustifrons) building a nest, Panguana Reserve, Huanuca Region, Peru.

Konrad Wothe / Russet-backed oropendola (Psarocolius angustifrons) bowing display, Panguana Reserve, Huanuca Region, Peru.

Konrad Wothe / Russet-backed oropendola (Psarocolius angustifrons) building a nest, Panguana Reserve, Huanuca Region, Peru.

Konrad Wothe / Russet-backed oropendola (Psarocolius angustifrons) building a nest, Panguana Reserve, Huanuca Region, Peru.

Konrad Wothe / Russet-backed oropendola (Psarocolius angustifrons) building a nest, Panguana Reserve, Huanuca Region, Peru.

Konrad Wothe / Russet-backed oropendola (Psarocolius angustifrons) building a nest, Panguana Reserve, Huanuca Region, Peru.

Konrad Wothe / Russet-backed oropendola (Psarocolius angustifrons) bowing display, Panguana Reserve, Huanuca Region, Peru.

Konrad Wothe / Russet-backed oropendola (Psarocolius angustifrons) bowing display, Panguana Reserve, Huanuca Region, Peru.

Konrad Wothe / Russet-backed oropendola (Psarocolius angustifrons) building a nest, Panguana Reserve, Huanuca Region, Peru.

Dong Lei / Russet sparrow (Passer rutilans) perched, Lantsang Mekong river, Kawakarpo Mountain, Meri Snow Mountain National Park, Yunnan Province, China.

Dong Lei / Russet sparrow (Passer rutilans) perched, Lantsang Mekong river, Kawakarpo Mountain, Meri Snow Mountain National Park, Yunnan Province, China.

Dong Lei / Russet sparrow (Passer rutilans) feeding on insect, Lantsang Mekong river, Kawakarpo Mountain, Meri Snow Mountain National Park, Yunnan Province, China.

Paul Hobson / Russet toughshank (Collybia dryophila), Nottinghamshire, UK, November.

Tim Laman / Female Russet-backed Oropendula (Psarocolius angustifrons) building a nest at Napo Wildlife Center, Yasuni National Park, Orellana Province, Ecuador, July.

Tim Laman / Female Russet-backed Oropendula (Psarocolius angustifrons) at Napo Wildlife Center, Yasuni National Park, Orellana Province, Ecuador, July.

Tim Laman / Female Russet-backed Oropendula (Psarocolius angustifrons) at Napo Wildlife Center, Yasuni National Park, Orellana Province, Ecuador, July.

Bernard Castelein / Brown Mouse Lemur (Microcebus rufus) Ialasatra, Madagascar

Bernard Castelein / Brown Mouse Lemur (Microcebus rufus) Ialasatra, Madagascar

Bernard Castelein / Brown Mouse Lemur (Microcebus rufus) Ialasatra, Madagascar

Tui De Roy / Russet crowned warbler (Basileuterus coronatus) Bellavista cloud forest private reserve, 1700m altitude, Tandayapa Valley, Andean cloud forest, Ecuador

David Welling / Russet-tipped Clubtail Dragonfly (Stylurus plagiatus) perching on foliage. Rio Grande Calley, Hidalgo County, Texas, USA.

Pete Oxford / Russet-crowned Warbler (Basileuterus coronatus) perched on lichen covered branch, captive, Podocarpus National Park, Ecuador

Gerrit Vyn / Willow Ptarmigan (Lagopus lagopus) male standing on snow covered ground, vocalising in spring courtship. Males retain the white body plumage of winter plumage and molt the head and neck feathers to th...

Gerrit Vyn / Willow Ptarmigan (Lagopus lagopus) male standing on snow covered ground, in spring. Males retain the white body plumage of winter plumage and molt the head and neck feathers to the russet brown summer...

Bryan and Cherry Alexander / Reindeer lichen (Cladonia sp.) and the autumn russet catkins of Dwarf birch (Betula nana) on the tundra in Hurry Inlet. Scoresbysund, East Greenland, September.

Andy Sands / Ruby Tiger moth (Phragmatobia fuliginosa) showing underwing, Hertforshire, England, UK

Andy Sands / Ruby Tiger moth (Phragmatobia fuliginosa) Hertforshire, England, UK

Rolf Nussbaumer / Giant Antpitta (Grallaria gigantea) adult, Paz de las aves, Mindo, Ecuador, Andes, South America, January

Rolf Nussbaumer / Dark-backed Wood-quail (Odontophorus melanonotus) adult, Mindo, Ecuador, Andes, South America, January

Rolf Nussbaumer / Chestnut-Breasted Coronet hummingbird (Boissonneaua matthewsii), adult perched, Papallacta, Ecuador, Andes, South America, January

Pete Oxford / Russet mouse lemur {Microcebus rufus} held in hand to show small size, Kirindy, madagascar

Pete Oxford / Russet mouse lemur {Microcebus rufus} Montagne D'ambre NP, Madagascar

Hermann Brehm / Russet backed oropendola (Psarocolius angustifrons) perched on branch, South America

Luiz Claudio Marigo / Russet-mantled foliage gleaner (ovenbird) at nest in termite mound, Brazil. Endangered.

Luiz Claudio Marigo / Russet-mantled foliage gleaner (ovenbird) at nest in termite mound, Brazil. Endangered.

Pete Oxford / Russet mouse lemur {Microcebus rufus} Kirindy, Madagascar

Pete Oxford / Russet mouse lemur held in hand {Microcebus rufus} captive, Kirindy Dry Forest Reserve, Madagascar

Thomas Marent / Russet-backed Oropendola (Psarocolius angustifrons) on nest, Manu, Peru

Thomas Marent / Russet-backed Oropendola (Psarocolius angustifrons), Guacharo Cave National Park, Colombia