Garden Warbler

Listen to example recordings of the main vocalisations of Garden Warbler, provided by xeno-canto contributors.

This species can be found on the following statutory and conservation listings and schedules.

UK Birds of Conservation Concern	Green listed
Species of European Conservation Concern	Least Concern
IUCN Red List of Threatened Species (global)	Least Concern
Schedule 1 license required (to disturb)	No
Birds Directive Annex 1	No
Listed on the Annexes of	Bern(III), Bonn(II)

Despite large short-term fluctuations in abundance, the CBC/BBS data suggest that the population may possibly be in long-term decline. Although the long-term trend does not raise alerts in this report due to wide confidence intervals, formal alerts have been raised in two of the last three reports. The BBS map of change in relative density between 1994-96 and 2007-09 indicates that strong decreases in southern and eastern Britain over that period contrasted with increases in the west and north. There has been a decline across Europe since 1980 (PECBMS: PECBMS 2020a>).

UK breeding population

No population change in UK (1967–2022)

Garden Warblers favour scrub, copses and woodland edge throughout England, Wales and southern and central Scotland; farther north they are distributed more patchily, occurring in northeast Scotland, Strathspey and along the Great Glen. Garden Warblers are scarce in Ireland.

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Occupied 10-km squares in UK

No. occupied in breeding season	2096
% occupied in breeding season	69
No. occupied in winter	18
% occupied in winter	0.6

European Distribution Map

European Breeding Bird Atlas 2

Breeding Season Habitats

Most frequent in	Scrub
Also common in	Deciduous Wood

Relative frequency by habitat

Relative occurrence in different habitat types during the breeding season.

Since the 1968–72 Breeding Atlas there has been a 12% increase in Garden Warbler range in Britain & Ireland. These increases are most evident in the west and north of the range, in Ireland, Northumberland and Scotland. Increases are also apparent on low ground around the Fens and in Lancashire.

Garden Warbler is a summer visitor, arriving from mid April. When not singing it is much harder to detect and is recorded at low levels during autumn migration.

View a summary of recoveries in the Online Ringing Report.

Foreign locations of birds ringed or recovered in Britain & Ireland

View number ringed each year in the Online Ringing Report

Maximum Age from Ringing	10 years 1 months 6 days (set in 2015)
Typical Lifespan	2 years with breeding typically at 1 year
Adult Survival	0.5±0.045
Juvenile Survival	0.265 (in first year)

Wing Length	Adults	77.9±2 | Range 75–81mm, N=6566
	Juveniles	77±2.1 | Range 74-81mm, N=8124
	Males	78±2.1 | Range 75–81mm, N=1017
	Females	77.7±1.9 | Range 75–81mm, N=1859

Body Weight	Adults	17.2±1.6 | Range 15.2–20.4g, N=5834
	Juveniles	18.5±2.3 | Range 15.4–23.0g, N=7512
	Males	16.7±1.1 | Range 15.2–18.5g, N=894
	Females	17.5±1.6 | Range 15.4–20.5g, N=1612

Feather measurements and photos on featherbase

Ring size	A (pulli B)
Field Codes	2-letter: GW | 5-letter code: GARWA | Euring: 12760

For information in another language (where available) click on a linked name

Causes of change

The causes of change in Garden Warbler abundance are unclear, but the decline is most likely to be driven by reduced productivity or juvenile survival.

Further information on causes of change

Garden Warbler abundance has varied alongside that of other trans-Saharan migrant warblers (Siriwardena et al. 1998b), probably reflecting the influence of changes in their winter environment. Despite large short-term fluctuations in abundance, the CBC/BBS data suggest that the population may be in long-term decline. Analysis of annual population changes and winter survival estimates across western Europe shows only a weak relationship between survival and population change, suggesting than long-term population change may be driven by reduced productivity or juvenile survival (Johnston et al. 2016). CES survival rates for adults have decreased, and there have been increases in nest failure rates and corresponding declines in the number of fledglings per breeding attempt. Post-fledging productivity, as measured by the CES, has also declined sharply since 1983. The negative effects of deer browsing are particularly strong for Garden Warbler (Holt et al. 2011) and hence a reduction in understorey habitat could potentially be a factor which has contributed towards the observed trends, though this has not been confirmed.

Information about conservation actions

The main drivers of change for Garden Warbler are not known and may possibly reflect changes during winter, but productivity may play a role and therefore conservation actions to improve breeding habitat could benefit this species. Mustin et al. (2014) found that the change in vegetation cover at 0.5 to 2 m above ground was the most important factor determining colonization or extinction by Garden Warbler, and suggested that habitat creation could help counteract possible future effects of future climate change.

The importance of understorey habitat to this species is also highlighted by another study which looked at the effects of deer browsing on bird species. The negative effects of deer browsing were particularly strong for Garden Warbler (Holt et al. 2011) and therefore actions to control deer numbers or exclosures to exclude deer are likely to help provide understorey habitat for this species, as well as other actions to encourage the growth of shrub layer vegetation.