Sedge Warbler

Listen to example recordings of the main vocalisations of Sedge 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	Amber 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)

The trend, though apparently a moderate decline, is uncertain because the long-term changes are partly obscured by shorter fluctuations in numbers. Numbers across Europe have been broadly stable since 1980 (PECBMS: PECBMS 2020a>).

UK breeding population

-38% decrease (1967–2022)

Sedge Warblers breed throughout Britain & Ireland, being absent or present at low density only in the uplands. In Britain they reach high densities in the lowlands, especially the fens, valleys and coastal marshes of eastern England, the Scottish Central Belt and parts of eastern Scotland. In Ireland, high densities are associated with the Shannon catchment and with inland waterbodies and coasts in the north.

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Occupied 10-km squares in UK

No. occupied in breeding season	2297
% occupied in breeding season	76
No. occupied in winter	1
% occupied in winter	0.03

European Distribution Map

European Breeding Bird Atlas 2

Breeding Season Habitats

Most frequent in

Reedbed, Along Rivers

Relative frequency by habitat

Relative occurrence in different habitat types during the breeding season.

The Sedge Warbler's breeding range contracted by 12% between 1968–72 and 1988–91 and then expanded by 17% up to 2008–11. Whilst the dip in range size in 1988–91 is consistent with under-recording, it should be borne in mind that Sedge Warbler populations fluctuate widely in response to wet-season rainfall in their West African wintering grounds and that a major population crash occurred in 1984/85.

Sedge Warbler is a summer visitor, arriving from early April with autumn migration extending into mid September.

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	8 years 8 months 8 days (set in 2001)
Typical Lifespan	2 years with breeding typically at 1 year
Adult Survival	0.224±0.031
Juvenile Survival	0.25 (in first year)

Wing Length	Adults	65.5±1.9 | Range 62–68mm, N=22838
	Juveniles	64.8±1.7 | Range 62-67mm, N=44228
	Males	66.3±1.6 | Range 64–69mm, N=5545
	Females	64.2±1.5 | Range 62–67mm, N=4969

Body Weight	Adults	11.4±1.1 | Range 10.0–13.2g, N=20329
	Juveniles	10.9±1.3 | Range 9.60–12.7g, N=41859
	Males	11.2±0.8 | Range 10.1–12.5g, N=4697
	Females	11.6±1.2 | Range 10.0–13.9g, N=4219

Feather measurements and photos on featherbase

Ring size	A
Field Codes	2-letter: SW | 5-letter code: SEDWA | Euring: 12430

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

Causes of change

Much of the year-to-year variation in population size is driven by changes in adult survival rates which, in turn, are related to changes in rainfall on their wintering grounds.

Further information on causes of change

Detailed analysis of BTO data sets has shown that much of the year-to-year variation in population size is driven by changes in adult survival rates which, in turn, are related to changes in rainfall on their wintering grounds, which lie just south of the Sahara Desert, in the West African Sahel (Peach et al. 1991), and analysis which also included additional data from western Europe also showed a strong relationship between overwinter survival and population change (Johnston et al. 2016). The smoothed CBC/BBS and WBS/WBBS trends show four troughs in population, related to years of poor West African rainfall, with a low point in 1984-85. The CES, which provides the biggest Sedge Warbler sample, shows the most recent three of the same troughs. Daily nest failure rates at the egg stage have increased slightly but the number of fledglings per breeding attempt has shown no change. CES productivity data show a sustained decrease since the late 1980s.

Information about conservation actions

This species shows fluctuating trends which are thought to be mainly driven by overwinter survival which is linked to rainfall on their wintering grounds. No significant problems have been identified on the breeding grounds and therefore few specific conservation actions have been proposed to benefit Sedge Warblers.

A study in the Netherlands found that Sedge Warblers preferred uncut reeds to cut reeds when choosing nest territories and that the areas of uncut reed had higher nesting densities and lower predation rates (Graveland 1999).