First record of interspecific cooperative breeding among redstart species

We report the first record of a single nest containing the young of a pair of Black Redstarts Phoenicurus ochruros and a pair of Common Redstarts Phoenicurus phoenicurus. All four parents provisioned the nestlings with food, and indiscriminately provided food to chicks of both species and with a very high overlap of activity rhythms. Our observation provides further evidence of the plasticity of these passerine bird species in brood management.