Nursing
As Ammenzucht refers to it when young animals are a kind of raised specifically due to human intervention by another species. For example, the occasional press reports of a female dog raising lion cubs or raccoon cubs are foster breeding.
In addition to these exceptional cases, there are regularly targeted foster breeds, especially in domestic and ornamental poultry, which have been practiced for a very long time. Certainly the oldest form is the use of particularly brooding chicks , to which the eggs of their fellow hens were pushed, which they willingly hatched with. The different breeding willingness of individual chicken breeds was also exploited in this way.
A similar process is also known in pigeon breeding. Breeders of particularly clumsy breeds that could otherwise easily crush the clutch or chicks, as well as breeders of short-beaked breeds who cannot feed their young themselves, are often dependent on so-called foster pigeons to raise the young. As such, one usually uses small, light and breeding breeds such as. B. carrier pigeons , which the eggs are pushed under, provided the laying date of the eggs is not too far apart. The wet nurses hatch the "foreign" eggs and raise the young animals, which the "real" parents would not be able to do, or only with difficulty.
Nurse breeding also plays a role in the breeding of ornamental birds. The brightly colored Gouldian finches can therefore be offered so cheaply in the zoo animal trade because they were raised by rearing nurses. Above all, the Japanese developed the rearing of Gouldians after the Australian government banned the export of these and other wild animals from Australia on January 1, 1960. Japanese breeders mainly use Japanese gulls . In this ornamental bird species, both parent birds are busy breeders and they are easy to keep. Breeders achieved the greatest breeding success when the young Gouldian finches were raised by three male gulls each. Like most of the finches, Gouldian finches always lay new clutches when their eggs have been stolen. A single pair of Gouldian finches produces up to 60 eggs per year; it takes three groups of three Japanese gulls to raise the young birds of this couple.
This nursing practice is practiced worldwide today. In the Netherlands in particular there are producers who use Gouldian finches in this way for the European market. According to the experience of the finch expert Horst Bielefeld , birds that descend from parent birds that have to produce eggs almost without a break are particularly susceptible to disease. Their mortality rate during the first moult is said to be around 50 percent. The birds are also often misrepresented, that is, they see their sexual partners in the gulls and court them while they take no notice of their conspecifics. Gouldian finches, which have an incorrectly developed breeding and feeding instinct, also reproduce through nursing. Lovers who want to set up a natural breed with these birds have the experience that these Gouldian finches breed unreliably, do not feed their young or throw them out of the nest.