Parasitic Chicks Research Articles

Should a parasite expose itself? (Some theoretical aspects of begging and vigilance behavior)

This paper examines the evolutionarily stable (ESS) solution of the begging conflict in cases involving nest parasitization. As expected, the presence in the nest of a parasite chick leads to a more intense begging conflict, with the parasite displaying a more selfish behavior than the host chicks. The model also predicts opposite responses by the host and the parasite to changes in the number of nestmates. While a larger number of nestmates entails a reduced ESS begging intensity for each of the host chicks, it entails an increased begging intensity for the parasite. Consequences of the parasite's ability to disguise itself are compared to analogous results for the vigilance game: whereas in the begging game a parasite should conceal itself, exposure can be selectively advantageous for a defector in the vigilance game.

An investigation into egg-acceptance by azure-winged magpies and host-recognition by great spotted cuckoo chicks

Tests using magpie's eggs (which are very similar to those of the great spotted cuckoo) on azure-winged magpies ( Cyanopica cyanea) showed that the latter accept strange eggs, rejecting only 25% of them. We therefore suggest that they are an accepter species, and as such a substitute host species for the great spotted cuckoo ( Clamator glandarius). We suggest a theory for the transition from ‘Accepter Species’ to ‘Non-mimetic-egg Rejecter Species’ by hosts of specialist brood parasites. We have obtained evidence of host recognition by great spotted cuckoo chicks of typical or atypical host species characteristics. Basing our theory on the calls of parasitic chicks reared in the nests of the azure-winged magpies and magpies ( Pica pica), we suggest that the foregoing is the mating mechanism necessary for the parasitization of a new host species.