FEEDING OF NESTLING AND FLEDGLING BROOD PARASITES BY INDIVIDUALS OTHER THAN THE FOSTER PARENTS - A REVIEW

We summarize 67 reports of 13 species of brood-parasitic young, mostly fledglings, being fed by individuals other than the host. We refer to this behavior as auxiliary feeding. The parasite gains extra food res ources, whereas the adult that feeds the parasite appears to behave ma ladaptively. The parasite may present a supernormal stimulus, manipula ting unrelated adults into feeding it. Most auxiliary feedings were ob served in brood parasites that were raised by small hosts. Host specif icity, vocal mimicry, visual mimicry, and nestling competition apparen tly were not associated with the number of records of auxiliary feedin gs; however, the trends could not be analyzed statistically because of the anecdotal nature of the observations for each species. Still to b e determined is whether obtaining auxiliary feeding is a strategy used by some brood-parasitic species, particularly the pallid cuckoo (Cucu lus pallidus).