Song thrush thrush recognizes the cuckoo's non-mimetic eggs. However, the song thrush does not demonstrate the same aggression toward the adult cuckoo that is shown by the blackbird. The introduced birds in New Zealand, where the cuckoo does not occur, have, over the past 130 years, retained the ability to recognise and reject non-mimetic eggs. Adult birds may be killed by cats, little owls and sparrowhawks, and eggs and nestlings are taken by magpies, jays, and, where present, grey squirrels. As with other passerine birds, parasites are common, and include endoparasites, such as the nematode "Splendidofilaria (Avifilaria) mavis" whose specific name "mavis"
Dusky thrush black and the belly and undertail are white. Naumann's thrush in comparison has a paler brown back and head; the face, breast, flank spots and rump are reddish, and the belly and undertail are white. The female is fairly similar to the male, but immatures have a weaker patterning. The male dusky thrush has a simple fluted or whistling song, similar to the redwing. There are suggestions that the songs of dusky and Naumann's thrush differ. Dusky thrush The dusky thrush ("Turdus eunomus") is a member of the thrush family which breeds eastwards from central Siberia. It is closely related