BirdTrends 2012 - BTO - British Trust for Ornithology

Species links

Alphabetic species...

Taxonomic species...

Section links

Population changes
Demographic trends

Additional info

Chaffinch
Fringilla coelebs

Key facts

Conservation listings: Europe: no SPEC category (concentrated in Europe, conservation status favourable) (BiE04)
UK: green (species level); amber (race gengleri, >20% of European breeders) (BoCC3)
Long-term trend: UK, England: shallow increase
Population size: 6.2 million territories in 2009 (APEP13: 1988-91 Atlas estimate updated using CBC/BBS trend)

http://www.bto.org/birdtrends2010/images/chaff1THjpg.jpg

Status summary

Chaffinch abundance has increased rapidly since the early 1970s, according to CBC/BBS and CES, but numbers seemed to stabilise for a period during the 1990s. This relative stability was associated with a reduction in annual survival, which could be density-dependent (Siriwardena et al. 1999). There was also some evidence of improved breeding performance during the early years of population increase, with larger broods, fewer egg-stage nest failures, and more fledglings per breeding attempt, but these trends are now reversed. The BBS map of change in relative density between 1994-96 and 2007-09 indicates that there have been decreases in a band from eastern Northern Ireland across Wales to Devon and Dorset, outweighed by increases elsewhere. The downturn in numbers since 2006 is linked to the widespread and severe outbreak of trichomonosis that began in 2005, being greatest in areas with a high incidence of the disease (Robinson et al. 2010). The trend towards earlier laying may be partly explained by recent climate change (Crick & Sparks 1999). Chaffinches are well adapted to suburban and garden habitats, as well as to highly fragmented woodland and hedgerows, occurring less in the open-field, arable habitats that have been affected most by agricultural intensification, so it is possible that they have benefited by environmental changes from which other seed-eating passerines have suffered. Numbers have shown widespread moderate increase across Europe since 1980, though with little change since 1990 (PECBMS 2012a).

Population changes in detail

Source	Period (yrs)	Years	Plots (n)	Change (%)	Lower limit	Upper limit	Alert	Comment
CBC/BBS UK	43	1967-2010	1047	28	15	43
	25	1985-2010	1644	12	5	18
	10	2000-2010	2726	5	2	8
	5	2005-2010	3096	-1	-3	2
CBC/BBS England	43	1967-2010	829	30	14	44
	25	1985-2010	1292	12	5	19
	10	2000-2010	2131	3	0	6
	5	2005-2010	2437	-5	-7	-3
CES adults	26	1984-2010	78	8	-39	74
	25	1985-2010	80	5	-36	62
	10	2000-2010	87	-9	-25	7
	5	2005-2010	84	-17	-27	-6
CES juveniles	26	1984-2010	61	51	-13	157
	25	1985-2010	62	83	14	210
	10	2000-2010	69	110	48	170
	5	2005-2010	66	25	-5	57
BBS UK	15	1995-2010	2428	12	8	15
	10	2000-2010	2710	5	2	8
	5	2005-2010	3096	0	-3	2
BBS England	15	1995-2010	1865	12	8	16
	10	2000-2010	2076	3	1	6
	5	2005-2010	2368	-4	-6	-2
BBS Scotland	15	1995-2010	238	15	5	27
	10	2000-2010	254	14	3	23
	5	2005-2010	298	10	2	17
BBS Wales	15	1995-2010	197	-4	-16	10
	10	2000-2010	222	5	-4	15
	5	2005-2010	234	-1	-8	7
BBS N.Ireland	15	1995-2010	89	41	7	56
	10	2000-2010	103	-11	-22	1
	5	2005-2010	111	-2	-8	5

Tables show changes with their 90% confidence limits. Alerts are flagged for significant changes only. See here for more information.

Demographic trends

More on demographic trends

Variable	Period (yrs)	Years	Mean annual sample	Trend	Modelled in first year	Modelled in 2010	Change	Alert	Comment
Fledglings per breeding attempt	42	1968-2010	114	Curvilinear	1.57 fledglings	1.41 fledglings	-10.4%
Clutch size	42	1968-2010	86	Curvilinear	4.23 eggs	4.07 eggs	-3.8%
Brood size	42	1968-2010	139	Curvilinear	3.60 chicks	3.56 chicks	-1.1%
Nest failure rate at egg stage	42	1968-2010	164	Curvilinear	3.04% nests/day	3.84% nests/day	26.3%
Nest failure rate at chick stage	42	1968-2010	114	Curvilinear	3.00% nests/day	3.12% nests/day	4.0%
Laying date	42	1968-2010	107	Linear decline	May 12	May 2	-10 days
Juvenile to Adult ratio (CES)	26	1984-2010	84	Smoothed trend	43 Index value	100 Index value	134%
Juvenile to Adult ratio (CES)	25	1985-2010	86	Smoothed trend	53 Index value	100 Index value	90%
Juvenile to Adult ratio (CES)	10	2000-2010	95	Smoothed trend	66 Index value	100 Index value	51%
Juvenile to Adult ratio (CES)	5	2005-2010	90	Smoothed trend	88 Index value	100 Index value	13%

For details of analytical methods for the Nest Record Scheme, the Constant Effort Sites (CES) and the Retrapping Adults for Survival (RAS) scheme, please follow links here.