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"
Varied thrush Varied thrush The varied thrush ("Ixoreus naevius") is a member of the thrush family, Turdidae. The German naturalist Johann Friedrich Gmelin described the varied thrush in 1789. Four subspecies are recognised: The genus name "Ixoreus" comes from the Ancient Greek "ixos", "mistletoe". This was a synonym of a former name for the mockingbird genus, "Mimus"; the genus creator Bonaparte assumed wrongly that, because Swainson had shown a mockingbird and this thrush on the same plate of his book, they were related. The specific "naevius" is Latin for "spotted" from "naevus", " spot". The varied thrush is a fairly large thrush