BTO - Breeding Birds of the Wider Countryside: Song Thrush

SONG THRUSH
Turdus philomelos

• Population
changes

• Productivity
trends

• Additional
information

Conservation listings

Europe: no SPEC category (concentrated in Europe, conservation status favourable)
UK: red (>50% population decline)
UK Biodiversity Action Plan: click here

Long-term trend

UK, England: rapid decline

UK population size

1,144,000 territories in 2000 (1988–91 Atlas estimate updated using CBC/BBS trend: BiE04, APEP06)

Status summary

CBC/BBS shows a rapid decline in Song Thrush abundance that began in the mid 1970s. The second half of this decline can also be seen in the CES index. CES productivity showed an initial decrease, followed by some partial recovery, and NRS data indicate that nest success has improved since 1981. Changes in survival in the first winter, and perhaps also the post-fledging period, are sufficient to have caused the population decline (Thomson et al. 1997, Siriwardena et al. 1998a, Robinson et al. 2004). The environmental causes of these changes are not known, but changes in farming practices, land drainage, pesticides and predators are all possible contributors (Fuller et al. 1995, Robinson et al. 2004). In woodland, drainage of damp ground and the depletion of woodland shrub layers through canopy closure and deer browsing may also be implicated (Fuller et al. 2005). Recent CBC/BBS data show a general increase, but population levels remain relatively low. Recovery of rural Song Thrush populations requires challenging new policy initiatives that should aim to restore nesting cover in scrub and woodland understorey, grazed grassland in arable-dominated areas, and damper soils in summer (Peach et al. 2004).

Population changes

CBC/BBS UK graph

Table of population changes for Song Thrush

Source	Period (yrs)	Years	Plots (n)	Change (%)	Lower limit	Upper limit	Alert	Comment
CBC/BBS UK	39	1967-2006	678	-51	-58	-43	>50
	25	1981-2006	939	-16	-27	-5
	10	1996-2006	1830	23	17	29
	5	2001-2006	1975	4	0	6
CBC/BBS England	39	1967-2006	540	-51	-60	-42	>50
	25	1981-2006	740	-18	-30	-6
	10	1996-2006	1422	24	19	29
	5	2001-2006	1528	8	4	11
CES adults	22	1984-2006	81	-17	-35	1
	10	1996-2006	88	-2	-17	10
	5	2001-2006	83	1	-12	12
CES juveniles	22	1984-2006	66	-45	-59	-22	>25
	10	1996-2006	75	20	0	38
	5	2001-2006	73	7	-11	25
BBS UK	11	1995-2006	1690	22	17	28
	10	1996-2006	1743	22	17	27
	5	2001-2006	1975	5	2	9
BBS England	11	1995-2006	1310	22	17	28
	10	1996-2006	1347	23	19	29
	5	2001-2006	1528	10	7	12
BBS Scotland	11	1995-2006	148	20	2	41
	10	1996-2006	151	19	3	39
	5	2001-2006	161	0	-11	11
BBS Wales	11	1995-2006	156	32	18	50
	10	1996-2006	162	30	17	45
	5	2001-2006	191	2	-5	9
BBS N.Ireland	11	1995-2006	67	47	16	76
	10	1996-2006	73	37	15	54
	5	2001-2006	85	0	-13	13

CBC/BBS England graph

CES adult abundance graph

CES juvenile abundance graph

BBS UK graph

BBS England graph

BBS Scotland graph

BBS Wales graph

BBS N Ireland graph

Productivity trends

Table of productivity changes for Song Thrush

Variable	Period (yrs)	Years	Mean annual sample	Trend	Modelled in first year	Modelled in 2006	Change	Comment
Clutch size	38	1968-2006	166	None
Brood size	38	1968-2006	182	None
Daily failure rate (eggs)	25	1981-2006	320	Curvilinear	4.37% nests/day	4.78% nests/day	9.4%
Daily failure rate (chicks)	25	1981-2006	240	None
Laying date	38	1968-2006	191	None
Juvenile to Adult ratio (CES)	22	1984-2006	88	Smoothed trend	159 Index value	100 Index value	-37% >25
Juvenile to Adult ratio (CES)	10	1996-2006	98	Smoothed trend	88 Index value	100 Index value	14%
Juvenile to Adult ratio (CES)	5	2001-2006	93	Smoothed trend	99 Index value	100 Index value	1%

Clutch size graph

Brood size graph

Egg nest failure graph

Chick nest failure graph

Laying date graph

CES productivity graph

Additional information


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This report should be cited as: Baillie, S.R., Marchant, J.H., Leech, D.I., Joys, A.C., Noble, D.G., Barimore, C., Grantham, M.J., Risely, K. & Robinson, R.A. (2009). Breeding Birds in the Wider Countryside: their conservation status 2008. BTO Research Report No. 516. BTO, Thetford. (http://www.bto.org/birdtrends) Pages maintained by Iain Downie, Mandy T Andrews and Laura Smith: Last updated 18.02.2009