BTO - Breeding Birds of the Wider Countryside: Spotted Flycatcher

SPOTTED FLYCATCHER
Muscicapa striata

• Population
changes

• Productivity
trends

• Additional
information

Conservation listings

Europe: SPEC category 3, declining
UK: red (>50% population decline)
UK Biodiversity Action Plan: click here

Long-term trend

UK, England: rapid decline

UK population size

63,700 territories in 2000 (1988–91 Atlas estimate updated using CBC/BBS trend: BiE04, APEP06)

Status summary

Spotted Flycatchers have declined rapidly and consistently since the 1960s and the CBC/BBS decline is also reflected in the trend revealed by CES. Productivity measures indicate greater nest losses at the chick stage, and a decrease overall in the ratio of juveniles to adults. Demographic modelling shows that decreases in the annual survival rates of birds in their first year of life are most likely to have driven the decline (Freeman & Crick 2003). Decreasing survival rates may have been caused by deteriorations in woodland habitats, particularly leading to declines in large flying insects, or by conditions either on the wintering grounds or along migration routes (Fuller et al. 2005). Since trends have been similar across UK regions and habitats, however, it is more likely that the decline has been driven by factors operating outside the UK. A predator 'control' experiment has suggested that the abundance of the introduced grey squirrel and other nest predators may be determining the breeding success of Spotted Flycatchers, especially in woodland, where nest success was lower overall than in gardens (Stoate & Szczur 2006).

Population changes

Table of population changes for Spotted Flycatcher

Source	Period (yrs)	Years	Plots (n)	Change (%)	Lower limit	Upper limit	Alert	Comment
CBC/BBS UK	38	1967-2005	118	-84	-89	-78	>50
	25	1980-2005	136	-79	-84	-72	>50
	10	1995-2005	219	-23	-31	-9
	5	2000-2005	200	-10	-22	1
CBC/BBS England	38	1967-2005	91	-87	-91	-80	>50
	25	1980-2005	102	-81	-87	-74	>50
	10	1995-2005	158	-29	-39	-15	>25
	5	2000-2005	140	-20	-31	-9
CES adults	21	1984-2005	15	-34	-80	27		Small sample
	10	1995-2005	13	2	-46	62		Small sample
	5	2000-2005	12	30	-30	125		Small sample
CES juveniles	21	1984-2005	11	-61	-84	-13	>50	Small sample
BBS UK	10	1995-2005	199	-27	-38	-12	>25
	5	2000-2005	194	-9	-23	4
BBS England	10	1995-2005	142	-33	-46	-22	>25
	5	2000-2005	136	-19	-30	-5

Productivity trends

Table of productivity changes for Spotted Flycatcher

Variable	Period (yrs)	Years	Mean annual sample	Trend	Modelled in first year	Modelled in 2005	Change	Comment
Clutch size	37	1968-2005	82	Curvilinear	4.22 eggs	4.16 eggs	-1.6%
Brood size	37	1968-2005	132	Curvilinear	3.61 chicks	3.61 chicks	-0.1%
Daily failure rate (eggs)	37	1968-2005	123	Curvilinear	1.77% nests/day	1.78% nests/day	0.6%
Daily failure rate (chicks)	37	1968-2005	110	Linear increase	0.96% nests/day	1.47% nests/day	53.1%
Laying date	37	1968-2005	73	None
Juvenile to Adult ratio (CES)	21	1984-2005	21	Smoothed trend	102 Index value	100 Index value	-2%
Juvenile to Adult ratio (CES)	10	1995-2005	18	Smoothed trend	80 Index value	100 Index value	25%	Small sample
Juvenile to Adult ratio (CES)	5	2000-2005	16	Smoothed trend	134 Index value	100 Index value	-26%	Small sample

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