BTO - Breeding Birds of the Wider Countryside: Willow Tit

WILLOW TIT
Poecile montana

• Population
changes

• Productivity
trends

• Additional
information

Conservation listings

Europe: no SPEC category (favourable conservation status in Europe, not concentrated in Europe)
UK: red (>50% population decline)
UK Biodiversity Action Plan: in preparation

Long-term trend

UK, England: rapid decline

UK population size

8,500 territories in 2000 (1988–91 Atlas estimate updated using CBC/BBS trend: BiE04, APEP06)

Status summary

Willow Tits have been in decline since the mid 1970s, and have become extinct in an ever-growing number of former haunts. The continuing decline in the CBC/BBS index through the 1990s, following a brief period of stability during the 1980s, is replicated in the CES abundance trend. The UK conservation listing has recently been upgraded from amber to red. Numbers have changed least in the wet woodlands that the species prefers (Siriwardena 2004). Farmland is now only rarely occupied. The most likely causes of decline are competition with other tit species, increasing nest predation by Great Spotted Woodpeckers, and deterioration in the quality of woodland as feeding habitat for Willow Tits through canopy closure and increased browsing by deer (Perrins 2003, Siriwardena 2004, Fuller et al. 2005). Numbers have fallen widely in Europe since 1980 (PECBM 2006).

Population changes

Table of population changes for Willow Tit

Source	Period (yrs)	Years	Plots (n)	Change (%)	Lower limit	Upper limit	Alert	Comment
CBC/BBS UK	38	1967-2005	42	-83	-91	-71	>50
	25	1980-2005	44	-80	-89	-70	>50
	10	1995-2005	62	-61	-70	-47	>50
	5	2000-2005	46	-32	-49	-16	>25
CBC/BBS England	38	1967-2005	39	-82	-91	-69	>50
	25	1980-2005	40	-81	-91	-70	>50
	10	1995-2005	55	-61	-71	-50	>50
	5	2000-2005	39	-35	-52	-18	>25
CES adults	21	1984-2005	20	-56	-87	-21	>50
	10	1995-2005	17	-50	-82	-22	>25	Small sample
CES juveniles	21	1984-2005	29	-46	-72	-12	>25
	10	1995-2005	24	-42	-69	-20	>25
	5	2000-2005	15	-5	-41	31		Small sample
BBS UK	10	1995-2005	53	-62	-70	-47	>50
	5	2000-2005	44	-34	-51	-18	>25
BBS England	10	1995-2005	46	-63	-72	-49	>50
	5	2000-2005	38	-36	-51	-18	>25

Productivity trends

Table of productivity changes for Willow Tit

Variable	Period (yrs)	Years	Mean annual sample	Trend	Modelled in first year	Modelled in 2005	Change	Comment
Juvenile to Adult ratio (CES)	21	1984-2005	32	Smoothed trend	102 Index value	100 Index value	-2%
Juvenile to Adult ratio (CES)	10	1995-2005	27	Smoothed trend	79 Index value	100 Index value	27%
Juvenile to Adult ratio (CES)	5	2000-2005	17	Smoothed trend	84 Index value	100 Index value	18%	Small sample

Insufficient data on clutch size
available for this species

Insufficient data on brood size
available for this species

Insufficient data on nest failure
available for this species

Insufficient data on nestling failure available for this species

Insufficient data on laying date
available for this species

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 16 January, 2008