Abstract
All finch breeders face the potential problem of finding a healthy nestling which has been purposefully or accidentally removed from the nest by its parents. The breeder has only a few options to save the baby - return the baby to the nest (if the nestling fell accidentally and its return will not cause abandonment of the nest by the parents), hand-feeding (not easy and not always successful), or fostering (if an appropriate pair is available). Fostering is the most common choice. However, the results of fostering are often not as good as expected, partly because breeders immediately think of society finches when there are other options. This article will suggest some alternatives to fostering finches under typical society (Bengalese) pairs.
Types of Fostering
Finch nestlings may be fostered to male/female pairs of societies, to "pairs" of societies of the same sex, to zebra finches, to closely related or similar species (e.g., red-cheeked cordon bleu to blue-capped cordon bleu), and to mixed pairs (male/female of different species) if the mixed pair has formed a pair bond. The following discussion will give two examples of fostering and then consider some aspects of what constitutes a "good" pair of foster parents.
An Unexpected Foster Pair
Recently two of my four fire finch nestlings (Lagonosticta senegala) were ejected from the nest, the first on day one and the second on day three. In an attempt to save them they were placed with the only pair of foster parents available - a female society and a male owl finch (Poepbila bicbenovii) which had been together for several months, had built a nest, and were incubating fostered eggs. The foster parents accepted the babies immediately. The fires were reared successfully with no live food and fledged at day 18, one day behind their siblings which were successfully raised by the natural parents. All four babies were equally strong and healthy. The diet for the fostered babies included the parents' usual fare1 and two daily feedings of Robert Black's formula for fostering finches.2 An evening feeding of Abba Green was also given.3 Feedings were provided at 6 a.m., 2 p.m., and 6 p.m. Interestingly, once fledged, the young only accepted food from the owl finch. The female society initially attempted to feed them, but the young only accepted food from their father. Preening and clumping continued with the society, however, and all four birds continued to behave as a typical family.
This fostering episode took place in a 12 x 12 x 32 inch cage located in the dining room less than three feet from the main conversation area. Clearly these circumstances are less than ideal for a successful fostering and raise the question of why this worked.
Cordon Bleus as Foster Parents One golden-breasted waxbill (Amandaua subflaua) was found beneath its nest which contained eggs and another newly-hatched nestling. Hesitant to disturb the nest, I fostered the baby to the most reasonable pair, a pair of redcheeked cordon bleus (Uraeginthus bengalus). The nestling could have been placed with societies then sitting on eggs, but the cordons were selected because the societies had already rejected a golden-breasted earlier in the season. Also societies are not likely to accept or succeed in rearing a goldenbreasted because this waxbill nestling differs in size and appearance compared to the societies' own young.
The cordons were sitting on their third infertile clutch and appeared pleased with the appearance of the baby. They fed the nestling from their usual diet, but relied heavily on Robert Black's fostering formula, a few very small meal worms ( 10-15 per day), some aphids and seedling grasses. The cordons were one year old and had never raised their own young. Again, the significant question associated with this fostering is why it worked at all.