Mark Carwardine / Chatham Island Tomtit (Petroica macrocephala) wild bird in garden, used as foster parent for saving the Chatham Island black robin from extinction, Chatham Islands, New Zealand

Ernie Janes / Male Blackbird (Turdus merula) feeding young Robin chicks (Erithacus rubecula) in nest, UK

Jerry Monkman / The Foster covered bridge in autumn landscape, Cabot, Vermont, USA, October 2009

Suzi Eszterhas / Two week orphaned Serval kitten (Leptailurus / Felis serval) being fed milk by foster parent, Suzi Eszterhas. Tanzania, Africa. October 2006

Suzi Eszterhas / Five week orphaned Serval kitten (Felis serval) with Suzi Eszterhas (Photographer / foster parent). Tanzania, Africa. October 2006

Suzi Eszterhas / Five week orphan Serval kitten (Leptailurus / Felis serval) in kangaroo pouch (used to increase emotional bond with foster parent). Tanzania, Africa. October 2006

Suzi Eszterhas / Five week orphan Serval kitten (Leptailurus / Felis serval) in kangaroo pouch (used to increase emotional bond with foster parent Suzi Eszterhas, Tanzania, Africa. October 2006

Nick Upton / 2020VISION / Common crane chick (Grus grus) reacting to surrogate parent in white costume, WWT Slimbridge, Gloucestershire, UK.

Jerry Monkman / Mouth of the Piscataqua River, Fort Foster and Whaleback Lighthouse at sunrise in winter, Kittery, New Hampshire, USA

Suzi Eszterhas / Serval (Leptailurus serval) kitten, five week old orphan in kangaroo pouch, used to increase emotional bond with foster parent, Masai Mara Reserve, Kenya

Suzi Eszterhas / Serval (Leptailurus serval) kitten, two and a half week old orphan playing and calling for foster mom, Masai Mara Reserve, Kenya

Suzi Eszterhas / Serval (Leptailurus serval) kitten, thirteen week old orphan playing with ostrich feather held by foster parent, Masai Mara Reserve, Kenya

Suzi Eszterhas / Serval (Leptailurus serval) kitten, five week old orphan in kangaroo pouch, used to increase emotional bond with foster parent, Masai Mara Reserve, Kenya

Jane Burton / Foster mother Jack Russell Terrier bitch licking tabby kittens as they suckle

Jane Burton / Sable Border Collie bitch fostering three orphan fox cubs (Vulpes vulpes).

Shattil & Rozinski / Foster Whooping cranes {Grus americanus} with Sandhill cranes {Grus canadensis} Texas, USA

Shattil & Rozinski / Peregrine falcon {Falco peregrinus} Denver, Colorado, USA. Wild foster mother of chicks hatched at Peregrine Fund, female had been injured, rehabilitated and released in previous year.

Jane Burton / Domestic Cat {Felis catus} red tabby 'Foster' drinking from pond.

Jane Burton / Domestic Cat {Felis catus} ginger mother with foster kittens.

Jane Burton / Domestic Cat {Felis catus} ginger mother with 5-week Persian x Burmese foster kittens, taken on after her own kittens were weaned.

Jane Burton / Domestic Cat {Felis catus} Ginger female 'Lucky' with grey-and-white foster kitten.

Colin Seddon / Chilean flamingo chick + Andean flamingo foster parent {P. andinus} Slimbrige WWT captive

John Downer / Nigel Williams, foster parent to imprinted Greylag chicks, swims in pool for filming of BBC tv series 'Supernatural'

John Downer / Nigel Williams acting as foster parent to imprinted Greylag chicks swims in pool for filming of BBC tv series 'Supernatural'

John Downer / Nigel Williams acting as foster parent to imprinted Greylag chicks for filming of BBC tv series 'Supernatural', 1998

John Downer / Nigel Williams swims with imprinted Greylag goose chicks for filming of BBC tv series 'Supernatural'

John Downer / Nigel Williams acting as foster parent to imprinted Greylag goose chicks for filming of BBC tv series 'Supernatural'

John Downer / Nigel Williams acting as foster parent to imprinted Greylag goose chicks for filming of BBC tv series 'Supernatural'

John Downer / Nigel Williams acting as foster parent to imprinted Greylag chicks for filming of BBC tv series 'Supernatural', 1998

John Downer / Nigel Williams acting as foster parent to imprinted Greylag goose chicks for filming of BBC tv series 'Supernatural'

John Downer / Nigel Williams with imprinted Greylag goose chicks following him - preparation for filming of BBC tv series 'Supernatural'

John Downer / Nigel Williams acting as foster parent to imprinted Greylag chicks, for filming of BBC tv series 'Supernatural'

Suzi Eszterhas / Serval (Leptailurus serval) five week old orphan kitten in kangaroo pouch which is used to increase emotional bond with foster parent, Masai Mara, Kenya