Song thrush

Turdus philomelos Brehm, 1831

Order: Passeriformes

Family: Turdidae

New Zealand status: Introduced

Conservation status: Introduced and Naturalised

Other names: thrush

Geographical variation: New Zealand birds have been assigned to the subspecies T. p. clarkei.

Song thrush. Adult. Wanganui, September 2010. Image © Ormond Torr by Ormond Torr

Song thrush. Adult. Wanganui, September 2010. Image © Ormond Torr by Ormond Torr

The song thrush is easily recognised by its speckled brown-on-cream breast. It is often heard before it is seen, as it is one of the main songsters of suburban New Zealand, with a very long singing season. Thrushes sing from a high branch, at the top of a tree or on power poles and lines. Their distinctive song comprising a wide range of notes, with each phrase typically repeated 2-3 times in succession. They are common throughout mainland New Zealand, Stewart Island, Chatham Islands and on many off-shore islands. Thrushes frequent a wide range of lowland and hilly habitats including suburban gardens, farmland, woodlands and some forests. They feed mostly on the ground on earthworms and snails, also insects and berries. Song thrushes were introduced from England, and were released widely in New Zealand from 1867.

Identification

The song thrush is smaller than a blackbird and is distinguished from the female blackbird by its pale cream underparts speckled with fawn-brown chevrons. The head, back and upper wings and tail are smooth grey-brown with indistinct streaking on the head.  In flight the upper wing is mostly uniform brown. The sexes are alike; juveniles have similar colouring but the speckling on the breast is less distinct.

Voice: distinctive and attractive song comprising a wide range of notes, often repeated, from about May to November, but calling can occur throughout the year. Calling can commence before sunrise. Singing is thought to be by males advertising territorial ownership.

Similar species: Eurasian blackbirds are larger and darker. Female and juvenile blackbirds are often confused with song thrushes, but do not have the thrush’s cream-coloured underparts overlaid with brown speckles.

Distribution and habitat

Song thrushes are widespread throughout New Zealand from sea level up to about 800 m altitude, lower in the south. They occur in urban areas, farmlands, orchards and in lowland indigenous forests. Song thrushes are resident on Stewart, Chatham, Kermadec and Snares Islands, and occur as vagrants at Auckland, Antipodes and Campbell Islands. They are less common on Great Barrier Island and in parts of Stewart Island, central Otago and coastal parts of Fiordland.

Population

The song thrush is a common bird in New Zealand, though Eurasian blackbirds are c.10 times more abundant than song thrushes in most habitats. Thrushes are usually seen as single birds or in pairs, and are not known to flock.

Ecological and economic impacts

Song thrushes are generally considered as being neutral or possibly slightly damaging in some situations to the rural economy. Although they eat snails and slugs, song thrushes can damage ripening fruit and spread the seeds of weedy plants. They have no recognised impacts on native bird species.

Breeding

Song thrushes are territorial and nest as solitary, monogamous pairs, breeding from August to February, peaking in September – November in most localities. They nest in the forks of shrubs or trees several metres above the ground and usually well concealed by foliage. The nest is a tightly woven bowl of grass, small twigs, lichen, wool, dead leaves and lightly lined with mud.  Two, three or more clutches of 3-4 (sometimes 5-6) eggs may be laid during a season especially if an earlier clutch is lost. The eggs are light blue-green or pale blue with tiny dark spots at the larger end. Incubation is mostly by the female and takes 12-13 days. Young are blind and naked when hatched and open their eyes after 5-6 days. They are well-feathered 12 days after hatching, and fledge at 12-14 days. Both sexes share feeding, including of fledglings.

Behaviour and ecology

Song thrushes are usually seen singly or in pairs. They are best known for their varied and attractive song, hence the name, given mostly in winter, spring and early summer. They are commonly seen feeding on the ground in parklands, woodlands and suburban gardens, walking slowly or running short distances looking for food. Like blackbirds, they tend to ‘listen’ for food, e.g. earthworms, beneath the ground surface. They are well known to break the shell of snails to get at the soft animal, by smashing the shell on a stone or path with a quick flick of the head. Although they are good flyers long flights seem to be infrequent. They are not considered to be migratory in New Zealand, although some local seasonal movement may occur. Moulting occurs in late summer – autumn.

Food

Song thrushes mainly eat earthworms, various insects, spiders, snails and slugs found on lawns, under trees, hedges, forests or in woodlands. They are also eat the small berries of some shrubs such as coprosma, and can eat ripening fruit in orchards.

Websites

http://en.wikipedia.org/wiki/Song_Thrush

http://www.nzbirds.com/birds/thrush.html

References

Gill, B.J. 2010. Passeriformes. Pp. 275-322 in Checklist Committee (OSNZ) 2010. Checklist of the birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica (4th ed.). Ornithological Society of New Zealand & Te Papa Press, Wellington.

Heather, B.D.; Robertson, H.A. 1996. The field guide to the birds of New Zealand. Viking, Auckland.

Higgins,P.J.; Peter, J.M.; Cowling, S.J. (eds.) 2006. Handbook of Australian, New Zealand and Antarctic birds. Vol. 7, boatbill to starlings. Oxford University Press, Melbourne.

Robertson, C.J.R.; Hyvonen, P.; Fraser, M.J.; Pickard, C.R. 2007. Atlas of bird distribution in New Zealand, 1999-2004. Ornithological Society of New Zealand, Wellington.

Recommended citation

Armitage, I. 2013. Song thrush. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz

Song thrush

Social structure
monogamous
Breeding season
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Nest type
woven cup
Nest description
Tightly woven bowl of grass, small twigs, lichen, wool, dead leaves and lightly lined with mud.
Nest height (min)
2 m
Nest height (max)
6 m
Maximum number of successful broods
4
Clutch size (min)
2
Clutch size (max)
3
Mean egg dimensions (length)
27 mm
Mean egg dimensions (width)
20 mm
Egg colour
Light blue-green or pale blue with tiny dark spots at the larger end
Egg laying dates
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Interval between eggs in a clutch
24 hours days
Incubation behaviour
female only
Incubation length (min)
12 days
Incubation length (max)
14 days
Nestling type
altricial
Nestling period (min)
12 days
Nestling period (max)
14 days
Age at fledging (min)
12 days
Age at fledging (max)
14 days
Age at independence (min)
28 days
Age at independence (max)
30 days
Age at first breeding (typical)
Probably 1 year
Maximum longevity
5 years
Maximum dispersal
Juveniles probably disperse 10s of km.