page_title: Song thrush
section_title: Breeding and survival
hierarchical_section_title: Song thrush / Behaviour and ecology / Breeding and survival
caption_attribution_description: Turdus philomelos English: Song Thrush eggs at Apenheul Primate Park, a zoo in Apeldoorn, Netherlands.
context_page_description: The song thrush is a thrush that breeds across the West Palearctic. It has brown upper-parts and black-spotted cream or buff underparts and has three recognised subspecies. Its distinctive song, which has repeated musical phrases, has frequently been referred to in poetry.
  The song thrush breeds in forests, gardens and parks, and is partially migratory with many birds wintering in southern Europe, North Africa and the Middle East; it has also been introduced into New Zealand and Australia. Although it is not threatened globally, there have been serious population declines in parts of Europe, possibly due to changes in farming practices.
  The song thrush builds a neat mud-lined cup nest in a bush or tree and lays four to five dark-spotted blue eggs. It is omnivorous and has the habit of using a favourite stone as an "anvil" on which to break open the shells of snails. Like other perching birds, it is affected by external and internal parasites and is vulnerable to predation by cats and birds of prey.
context_section_description: The female song thrush builds a neat cup-shaped nest lined with mud and dry grass in a bush, tree or creeper, or, in the case of the Hebridean subspecies, on the ground. She lays four or five bright glossy blue eggs which are lightly spotted with black or purple; they are typically 2.7 cm × 2.0 cm (1.06 in × 0.79 in) size and weigh 6.0 g (0.21 oz), of which 6% is 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 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 recognize 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 derives from this thrush. A Russian study of blood parasites showed that all the fieldfares, redwings and song thrushes sampled carried haematozoans, particularly Haemoproteus and Trypanosoma. Ixodes ticks are also common, and can carry pathogens, including tick-borne encephalitis in forested areas of central and eastern Europe and Russia, and, more widely, Borrelia bacteria. Some species of Borrelia cause Lyme disease, and ground-feeding birds like the song thrush may act as a reservoir for the disease.
caption: Three eggs in a nest
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