Conspecific Brood Parasitism among Birds: the Effects of Phylogeny, Mode of Reproduction and Geographic Distribution

We updated the list of species for which conspecific brood parasitism (CBP) has been reported, and it contained 256 species. We used this list to examine the effects of four factors on the rate of CBP (defined as the percentage of species where CBP was observed in a family), namely, phylogeny, geographic distribution, mode of reproduction (i.e. altricial/precocial) and diversification rate (mean number of species per genus in a family). CBP is influenced by phylogeny, appears to have multiple origins and has evolved many times in various branches of the avian phylogeny tree. As already well known, it is much more prominent among precocial than altricial birds, in which in some families of the former, most species (around 60% among Anatidae) and in some small families, even all species engage in CBP. In contrast, among altricial birds the highest levels of CBP are much lower and are found in the Ploceidae (14.5% of species) and Turdidae (12.8%). Of the three other examined parameters, only the mode of reproduction was significantly related to the rate of CBP, but accounted for only similar to 2% of the variation. Diversification rate and geographic distribution area were not correlated with CBP. These results further confirm that CBP is influenced by phylogeny and mode of reproduction. Literature searches revealed that the rate of appearance of articles on CBP typically increased for several years, starting in the late 1970s and early 1980s, levelled off during the first decade of the twenty-first century and then declined. This would seem to represent a recent decline in interest in the CBP phenomenon.