BTO - Breeding Birds of the Wider Countryside: Dunnock

DUNNOCK
Prunella modularis

• Population
changes

• Productivity
trends

• Additional
information

Conservation listings

Europe: no SPEC category (concentrated in Europe, conservation status favourable)
UK: amber (25–50% population decline)
UK Biodiversity Action Plan: in preparation

Long-term trend

UK, England: moderate decline

UK population size

2,163,000 territories in 2000 (1988–91 Atlas estimate updated using CBC/BBS trend: BiE04, APEP06)

Status summary

Dunnock abundance fell substantially between the mid 1970s and mid 1980s, after a period of population stability. Some recovery has occurred throughout the UK since the late 1990s, but the species is still subject to amber listing. The cause of the decline remains unknown. In many lowland woods, canopy closure in the absence of forest management and increasing browsing pressure from deer are likely to have reduced the suitability of the habitat for this species (Fuller et al. 2005). There has been little variation in survival rates over time (Siriwardena et al. 1998a). Clutch and brood sizes increased as the population fell. Numbers have fallen widely in Europe since 1980 (PECBM 2006).

Population changes

Table of population changes for Dunnock

Source	Period (yrs)	Years	Plots (n)	Change (%)	Lower limit	Upper limit	Alert
CBC/BBS UK	38	1967-2005	655	-34	-44	-21	>25
	25	1980-2005	888	-12	-21	-1
	10	1995-2005	1801	21	17	27
	5	2000-2005	1896	10	7	14
CBC/BBS England	38	1967-2005	542	-38	-46	-29	>25
	25	1980-2005	731	-16	-25	-8
	10	1995-2005	1470	18	13	22
	5	2000-2005	1525	10	6	12
CES adults	21	1984-2005	94	-1	-16	14
	10	1995-2005	106	11	1	22
	5	2000-2005	99	11	0	20
CES juveniles	21	1984-2005	91	-8	-27	18
	10	1995-2005	105	8	-1	18
	5	2000-2005	99	2	-9	12
BBS UK	10	1995-2005	1693	21	16	26
	5	2000-2005	1868	11	8	14
BBS England	10	1995-2005	1375	16	10	20
	5	2000-2005	1500	11	7	13
BBS Scotland	10	1995-2005	112	35	11	59
	5	2000-2005	120	7	-4	19
BBS Wales	10	1995-2005	136	40	20	61
	5	2000-2005	162	21	12	32
BBS N.Ireland	10	1995-2005	59	91	29	134
	5	2000-2005	75	4	-4	22

Productivity trends

Table of productivity changes for Dunnock

Variable	Period (yrs)	Years	Mean annual sample	Trend	Modelled in first year	Modelled in 2005	Change
Clutch size	37	1968-2005	99	Linear increase	3.93 eggs	4.2 eggs	6.9%
Brood size	37	1968-2005	105	Linear increase	3.47 chicks	3.65 chicks	5.1%
Daily failure rate (eggs)	37	1968-2005	143	None
Daily failure rate (chicks)	37	1968-2005	116	Curvilinear	2.47% nests/day	2.72% nests/day	10.1%
Laying date	37	1968-2005	79	Linear decline	May 4	Apr 29	-5 days
Juvenile to Adult ratio (CES)	21	1984-2005	98	Smoothed trend	102 Index value	100 Index value	-2%
Juvenile to Adult ratio (CES)	10	1995-2005	111	Smoothed trend	101 Index value	100 Index value	-1%
Juvenile to Adult ratio (CES)	5	2000-2005	103	Smoothed trend	118 Index value	100 Index value	-15%

Additional information


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This report should be cited as: Baillie, S.R., Marchant, J.H., Crick, H.Q.P., Noble, D.G., Balmer, D.E., Barimore, C., Coombes, R.H., Downie, I.S., Freeman, S.N., Joys, A.C., Leech, D.I., Raven, M.J., Robinson, R.A. & Thewlis, R.M. (2007) Breeding Birds in the Wider Countryside: their conservation status 2007. BTO Research Report No. 487. BTO, Thetford. (http://www.bto.org/birdtrends) Pages maintained by Susan Waghorn and Iain Downie: Last updated 3 January, 2008