Rallus aquaticus (Linnaeus, 1758)
Family: Gruiformes > Rallidae
A member of the crake family, the Water Rail, with its long red bill and black-and-white striped sides, favour the lush dense vegetation associated with waterbodies and wet ground.
This is a species that is more often heard than seen, and this is one reason why this is such a difficult bird to census. It is thought that around 4,000 pairs breed in the UK.
During the winter the most common call is a ‘pig-like’ squeal and Water Rail squealing are often referred to as ‘sharming’. The species can be adversely affected during periods of prolonged freezing conditions, and individuals will move elsewhere in search of warmer conditions. Birds from Europe bolster numbers during the winter and the BirdTrack reporting rate graph shows records peaking at this time.
Select a topic for more facts and statistics about the Water Rail
Water Rail identification is often straightforward.
Listen to example recordings of the main vocalisations of Water Rail, provided by xeno-canto contributors.
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Status and Trends
Population size and trends and patterns of distribution based on BTO surveys and atlases with data collected by BTO volunteers.
This species can be found on the following statutory and conservation listings and schedules.
The Water Rail is a secretive species and hence difficult to monitor robustly. Atlas data show a small (6%) increase in the number of occupied 10-km squares in Britain since 1968–72, but it is uncertain whether this reflects a real change or differences in observer coverage (Balmer et al. 2013). The UK population has recently been estimated at 3,900+ pairs taking into account county estimates and dedicated site surveys (Francis et al. 2020). The species had been added to the list of species considered by the Rare Breeding Birds Panel in 2006 but it was dropped in 2018 as a result of this revised UK population estimate. The population is most likely to be stable or increasing, but this is uncertain due to the unreliability of monitoring.
|UK winter population||+48% increase (1995/96 to 2020/21)|
Breeding Water Rails are patchily distributed throughout the lowlands of Britain and Ireland. In winter they are twice as widespread in Britain perhaps because resident breeders are supplemented by migrants from continental Europe.
Occupied 10-km squares in UK
|No. occupied in breeding season||717|
|% occupied in breeding season||24|
|No. occupied in winter||1322|
|% occupied in winter||44|
European Distribution Map
Changes in range are difficult to interpret for this difficult to detect species.
Change in occupied 10-km squares in the UK
|% change in range in breeding season (1968–72 to 2008–11)||+0.4%|
|% change in range in winter (1981–84 to 2007–11)||+50.4%|
Water Rails are present throughout the year, sometimes heard in the breeding season but more often seen in winter months.
Information about movement and migration based on online bird portals (e.g. BirdTrack), Ringing schemes and tracking studies.
Lifecycle and body size information about Water Rail, including statistics on nesting, eggs and lifespan based on BTO ringing and nest recording data.
View number ringed each year in the Online Ringing Report
|Maximum Age from Ringing||8 years 9 months 30 days (set in 1996)|
|Wing Length||Adults||121.3±5.8 | Range 112–130mm, N=483|
|Juveniles||120±5.8 | Range 111-129mm, N=244|
|Males||126.3±3.2 | Range 122–131mm, N=217|
|Females||116±3.1 | Range 110–121mm, N=204|
|Body Weight||Adults||127±22.01 | Range 93.0–164g, N=429|
|Juveniles||117±22.8751 | Range 82.0–158g, N=218|
|Males||141±18.62 | Range 102–172g, N=186|
|Females||112±14.68 | Range 90.0–135g, N=188|
Feather measurements and photos on featherbase
|Ring size||D (pulli E)|
|Field Codes||2-letter: WA | 5-letter code: WATRA | Euring: 4070|
For information in another language (where available) click on a linked name
Interpretation and scientific publications about Water Rail from BTO scientists.
Causes of change
Given the difficulty in monitoring this species it is unclear whether there have been any changes in population, although it is likely that the population is stable or increasing (Francis et al. 2020). The small increase in range since 1968–72 could perhaps have been prompted by relatively mild winters during the 1990s and 2000s but it is unclear whether the increase is genuine and it may result simply from improved observer coverage (Balmer et al. 2013). Habitat restoration and creation for other reedbed specialists such as the Bittern may also have benefited the Water Rail.
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