Cuckoos have a reputation for dumping their eggs and sitting back while their offspring get free bed and board in another bird’s nest — but scientists say that the cuckoo may have been unduly maligned as a parasite of the bird world.

A 16-year study has found that crow families that were unwittingly hosting a cuckoo chick tended to have better survival rates. The scientists put this down to a noxious “rotten meat” smell emitted by the cuckoo fledgelings when stressed that was effective at keeping away cats and other predators.

Overall, this appeared to more than compensate for the strain of providing food for an extra chick.

The study focused on a population of spotted cuckoos in northern Spain which lays “parasitic” eggs in