Did avian heterospecific brood parasites evolve from a cooperatively breeding ancestor?

Abstract

The Cooperative Breeding Hypothesis (CBH) for the evolution of heterospecific brood parasitism (HBP) in birds, states that brood parasites evolved from a cooperatively breeding ancestor, presumably after a process involving conspecific brood parasitism as an initial evolutionary step. I tested this hypothesis by means of comparative analyses of the altricial parasitic taxa. The CBH was not supported, although some statistically not significant trends support the hypotheses which indicate conspecific brood parasitism as the initial step towards HBP.