Although the preponderance of evidence seems to be in favor of the habitat selection hypothesis, some evidence for natal philopatry has been observed in cuckoos and the majority of cuckoo eggs are found in nests and among eggs matching their foster species, which supports the nest site choice hypothesis, but does not invalidate any of the other hypotheses. It could also be the case that there is more than one mechanism of host selection at play here.
This suggests that while the majority of evidence supports habitat selection as a primary factor, observations of natal philopatry in cuckoos and the high frequency of eggs found in nests and among those of their foster species support the nest site choice hypothesis. However, this does not rule out other possible explanations for host selection.