BTO - Breeding Birds of the Wider Countryside: Willow Tit

WILLOW TIT
Parus montanus

Conservation listings

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

Long-term trend

UK, England: rapid decline

Distribution maps

Maps and statistics from British and Irish
atlases can be viewed here.

Status summary

Willow Tits have been in decline since the mid 1970s, and have become extinct in an increasing 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. The most likely cause of decline is a deterioration in woodland quality, through reductions in the amount of dead wood, woodland drainage, and the thinning of the shrub layer due to overgrazing by deer (Vanhinsbergh et al. 2001, Perrins 2003). On farmland, now only rarely occupied, increasing nest predation by Great Spotted Woodpeckers may have played a role; numbers have changed least in the wet woodlands that the species prefers (Siriwardena 2004).

Table of population changes for Willow Tit

Source	Period (yrs)	Years	Plots (n)	Change (%)	Lower limit	Upper limit	Alert	Comment
CBC/BBS UK	35	1967-2002	42	-77	-90	-60	>50
	25	1977-2002	43	-80	-90	-63	>50
	10	1992-2002	58	-60	-76	-41	>50
	5	1997-2002	61	-42	-59	-17	>25
CBC/BBS England	35	1967-2002	39	-78	-88	-62	>50
	25	1977-2002	40	-82	-91	-70	>50
	10	1992-2002	52	-65	-75	-51	>50
	5	1997-2002	54	-46	-63	-31	>25
CES adults	18	1984-2002	22	-53	.	.	[>50]
	10	1992-2002	22	-51	.	.	[>50]
	5	1997-2002	16	-33	.	.	[>25]	Small sample
CES juveniles	18	1984-2002	31	-41	.	.	[>25]
	10	1992-2002	32	-49	.	.	[>25]
	5	1997-2002	24	-31	.	.	[>25]
BBS UK	9	1994-2003	54	-55	-68	-37	(>50)
BBS England	9	1994-2003	48	-62	-74	-45	(>50)

Table of productivity information for Willow Tit

Variable Period
(yrs) Years Mean
annual
sample Trend Predicted
in first year Predicted
in last year Change Comment

Percentage juveniles (CES) 18 1984-2002 35 Smoothed trend 107 productivity index 102 productivity index -7%

Percentage juveniles (CES) 10 1992-2002 35 Smoothed trend 102 productivity index 102 productivity index -2%

Percentage juveniles (CES) 5 1997-2002 27 Smoothed trend 103 productivity index 102 productivity index -2%

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


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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., Beaven, L.P., Coombes, R.H., Downie, I.S., Freeman, S.N., Joys, A.C., Leech, D.I., Raven, M.J., Robinson, R.A. and Thewlis, R.M. (2005) Breeding Birds in the Wider Countryside: their conservation status 2004. BTO Research Report No. 385. BTO, Thetford. (http://www.bto.org/birdtrends) Pages maintained by Susan Waghorn and Iain Downie: Last updated 18 January, 2006