Bittern

Listen to example recordings of the main vocalisations of Bittern, 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)	Yes
Birds Directive Annex 1	Yes
Listed on the Annexes of	WCA(I), WBD(I), Bern(III), Bonn(II), AEWA, NERC (41)

Previously widespread, Bitterns becamee extinct in the UK in the late nineteenth century before returning and increasing to around 80 booming males in the 1950s (Brown et al. 2012). The number of Bitterns in the UK then declined to a low of 11 booming males in 1997 (Brown et al. 2012) but has subsequently increased and has been rising consistently over the last ten years, with a new record total of 227 pairs counted in 2019 (Eaton et al. 2021). The breeding range has consequently also expanded considerably over the 40 years since the 1968–72 Breeding Atlas (Balmer et al. 2013).

UK winter population

+300% increase (1995/96 to 2020/21)

The extensive wet reedbeds that Bitterns require for breeding are provided at clusters of sites in Kent, East Anglia, Somerset and Yorkshire. In winter, Bitterns are much more widespread and can be found at many smaller sites with a mix of reedbeds and pools and also along riverbanks.

A few areas along the Norfolk and Suffolk coastline, in the Norfolk Broads and in north Kent have recorded breeding Bitterns in all three breeding atlases. Recent gains at inland sites correspond with extensive habitat creation schemes.

Bitterns are recorded throughout the year, but most often in winter and in spring when its territorial booming calls can be heard, and when adults may be seen on provisioning flights.

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	11 years 11 months 16 days (set in 2012)
Typical Lifespan	4 years with breeding typically at 1 year
Adult Survival	0.7±0.05

Feather measurements and photos on featherbase

Ring size	J
Field Codes	2-letter: BI | 5-letter code: BITTE | Euring: 950

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Causes of change

Degradation of habitat was considered an important driver of the declines between the 1950s and the late 1990s, with water levels within reedbeds being important (Tyler et al. 1998, Brown et al. 2012). Bitterns require extensive reedbeds for breeding and the recent increases have been driven by conservation efforts which have led to existing reedbeds being restored and new sites being created. Ongoing management of habitat is likely to remain important especially in the face of likely effects of climate change in south-east England (Brown et al. 2012).