HULSCHER JB, NIENHUIS J & VOSLAMBER B (2020) Accidental, voluntary or forced adoption by Greater Canada Goose Branta canadensis?. LIMOSA 93 (2): 74-78.

A pair of Greater Canada Goose lost its offspring twice to adoption, two young in 2017 and eight in 2019. The adoption process could be followed in 2019. The female parent was brooding her 36 hour old chicks on a lawn. Suddenly three chicks slipped away and joined a family with three nine day old chicks, grazing just a few meters away. Three more chicks crossed over unseen. The chicks switched back and forth until the end of the next day, when all eight young remained with the foster family. No aggression was observed between the two pairs, of which both females were sisters.
Four possible adoption strategies are discussed: (1) possibly strong stimuli from the foster family influenced the imprinting process in the younger chicks, (2) adoption might have been intentional since the adopting pair was physically dominant and large families have greater survival value, (3) the parents let their chicks go voluntarily, being unable to rear them themselves, or (4) a combination of these three strategies.

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