Cross-fostering

In animal studies, genetically hypertensive offspring reared by normotensive dams have been shown to have lower blood pressure compared to the controls.

Besides this, hyperkinetic animals reared by a normal dam have been shown to have lower locomotor activity compared to its controls.

Analysis of maternal milk composition found higher concentrations of lipid after pouch young is transferred into their host mother.

[4] In selective livestock breeding cross-fostering can be used to combine desirable genetic qualities such as weight, fat distribution or appearance with environmentally influenced ones such as temperament.

Cross fostering has been used in conservation biology such as the rearing of black robin chicks by other species.

In this instance the species was so close to extinction, with literally a handful of surviving individuals and a single mother, there was little chance of raising many offspring.

However, two pairs of birds may share the same nest for a time, as they do not become aggressive until several eggs have been laid and incubation begins.

These natural experiments have been used by Australian ornithologists Graeme Chapman and Ian Rowley to investigate the relative importance of genes and environment.

Another situation where birds can imprint on the wrong song is when one species takes over the nest of another but fails to remove all of its eggs.