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"
Song thrush shell. The female incubates the eggs alone for 10–17 days, and after hatching a similar time elapses until the young fledge. Two or three broods in a year is normal, although only one may be raised in the north of the range. On average, 54.6% of British juveniles survive the first year of life, and the adult annual survival rate is 62.2%. The typical lifespan is three years, but the maximum recorded age is 10 years 8 months. The song thrush is occasionally a host of parasitic cuckoos, such as the common cuckoo, but this is very rare because the