Dong Lei / White-browed Rosefinch (Carpodacus thura) with Tibetan prayer flags featuring the 'wind horse'. Pamuling mountain, Qinghai-Tibetan Plateau, China,

D. Parer & E. Parer-Cook / Galapagos Land Iguana (Conolophus subcristatus) with a Small Ground-Finch (Geospiza fuliginosa) on its head removing parasites, Galapagos Islands, Ecuador

Pete Oxford / Small Ground Finch (Geospiza fuliginosa) being ringed for Avian pox research, Puerto Ayora, Santa Cruz Island, Galapagos, endemic

Pete Oxford / Finch specimens at the Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island, Galapagos Islands, L to R Top: Large Ground Finch (Geospiza magnirostris), Woodpecker Finch (Cactospiza pallidu...

Nick Hawkins / Small ground-finch (Geospiza fuliginosa) singing whilst perched on branch. Isabela Island, Galapagos.

Nick Hawkins / Small ground-finch (Geospiza fuliginosa). Santa Cruz Island , Galapagos.

Nick Hawkins / Small ground finch (Geospiza fuliginosa) feeding on ectoparasites found on Marine iguana (Amblyrhynchus cristatus). Isabela Island, Galapagos.

Nick Hawkins / Small ground finch (Geospiza fuliginosa) standing on Marine iguana (Amblyrhynchus cristatus) leg. Finches feed on ectoparasites on iguanas. Isabela Island, Galapagos.

Nick Hawkins / Small ground finch (Geospiza fuliginosa) feeding on ectoparasites on Marine iguana (Amblyrhynchus cristatus) leg. Isabela Island, Galapagos.

Nick Hawkins / Small ground finch (Geospiza fuliginosa) feeding on ectoparasites whilst standing on Marine iguana (Amblyrhynchus cristatus) leg. Isabela Island, Galapagos.

Nick Hawkins / Small ground finch (Geospiza fuliginosa) standing on Marine iguana (Amblyrhynchus cristatus) leg. The finches feed on ectoparasites on iguanas. Isabela Island, Galapagos.

Nick Hawkins / Common cactus finch (Geospiza scandens) perched on Prickly pear (Opuntia). San Cristobal Island, Galapagos.