BTO - Breeding Birds of the Wider Countryside

BLUE TIT
Cyanistes caeruleus

• Population
changes

• Productivity
trends

• Additional
information

Conservation listings

Europe: no SPEC category (concentrated in Europe, conservation status favourable)
UK: green

Long-term trend

UK, England: shallow increase

UK population size

3,535,000 territories in 2000 (1988–91 Atlas estimate updated using CBC/BBS trend: BiE04, APEP06)

Status summary

Blue Tit populations have increased in abundance, in parallel with those of Great Tits, with brief pauses in the long-term upward trend. The recent years of the CBC/BBS index show fluctuations but no clear trend. Food provision in gardens during winter and availability of nest boxes, which may reduce egg and nestling predation, have both increased and may have contributed to the rise in population. Decreasing clutch and brood sizes, and a substantial decline in the proportion of young birds in early autumn, have accompanied the population increase. Numbers have risen widely in Europe since 1980 (PECBM 2006).

Population changes

Table of population changes for Blue Tit

Source	Period (yrs)	Years	Plots (n)	Change (%)	Lower limit	Upper limit	Alert
CBC/BBS UK	38	1967-2005	726	44	32	59
	25	1980-2005	996	26	15	36
	10	1995-2005	2036	12	9	16
	5	2000-2005	2116	12	9	15
CBC/BBS England	38	1967-2005	598	41	24	58
	25	1980-2005	815	21	10	32
	10	1995-2005	1652	9	6	12
	5	2000-2005	1694	8	6	11
CES adults	21	1984-2005	95	11	-6	26
	10	1995-2005	107	1	-7	12
	5	2000-2005	99	11	0	23
CES juveniles	21	1984-2005	95	-34	-48	-13	>25
	10	1995-2005	108	-28	-36	-18	>25
	5	2000-2005	101	5	-7	18
BBS UK	10	1995-2005	1913	12	8	15
	5	2000-2005	2085	11	8	13
BBS England	10	1995-2005	1545	9	6	12
	5	2000-2005	1667	8	5	10
BBS Scotland	10	1995-2005	133	21	7	38
	5	2000-2005	137	22	8	36
BBS Wales	10	1995-2005	161	22	10	36
	5	2000-2005	191	18	11	28
BBS N.Ireland	10	1995-2005	65	31	-5	66
	5	2000-2005	80	17	8	33

Productivity trends

Table of productivity changes for Blue Tit

Variable	Period (yrs)	Years	Mean annual sample	Trend	Modelled in first year	Modelled in 2005	Change
Clutch size	37	1968-2005	131	Linear decline	9.41 eggs	8.57 eggs	-8.9%
Brood size	37	1968-2005	220	Curvilinear	8.04 chicks	7.01 chicks	-12.7%
Daily failure rate (eggs)	37	1968-2005	215	Linear decline	0.48% nests/day	0.23% nests/day	-52.1%
Daily failure rate (chicks)	37	1968-2005	165	Linear increase	0.64% nests/day	0.89% nests/day	39.1%
Laying date	37	1968-2005	173	Linear decline	May 3	Apr 26	-7 days
Juvenile to Adult ratio (CES)	21	1984-2005	99	Smoothed trend	180 Index value	100 Index value	-44% >25
Juvenile to Adult ratio (CES)	10	1995-2005	112	Smoothed trend	145 Index value	100 Index value	-31% >25
Juvenile to Adult ratio (CES)	5	2000-2005	104	Smoothed trend	100 Index value	100 Index value	0%

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