Mareca strepera (Linnaeus, 1758)
Family: Anseriformes > Anatidae
Slightly smaller than Mallard, Gadwall is a slimmer duck with a white speculum and (useful in flight) a whitish belly.
The Gadwall is a herbivorous surface-feeding duck that favours the more productive margins and shallower water of lakes and other waterbodies. It has been shown to exploit some deeper waterbodies thanks to a habit of stealing plant material collected by other waterbirds, including Coot.
As a breeding species, Gadwall is thought to have become established with the aid of introductions during the 1850s, since when the population has increased. Winter numbers are swelled through the arrival of individuals from both the Continent and Iceland.
Select a topic for more facts and statistics about the Gadwall
Gadwall identification is sometimes difficult. The following article may help when identifying Gadwall.
Ducks are usually easy to identify, but the females can be more challenging. Many of our familiar dabbling ducks have subtly-plumaged brown females which, on first glance, appear similar. This workshop will help you tell them apart with confidence.
Listen to example recordings of the main vocalisations of Gadwall, provided by xeno-canto contributors.
Develop your bird ID skills with our training courses
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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.
Since wildfowlers released a wing-clipped pair of migrants in Norfolk in 1850, far from their native UK breeding distribution in Scotland, the breeding distribution of Gadwall has expanded and now covers much of lowland Britain, though with many gaps still in the west of the country (Balmer et al. 2013). Range expansion has been rapid since the 1950s. Numbers have recently surpassed the level where a BBS trend can be calculated: further strong increases are indicated and the population may even have redoubled over the latest 10-year period. Winter numbers, which include many continental visitors, have also risen strongly in England, Wales and Scotland, but show recent signs of levelling off in England (since around 2010/11) and have fluctuated in Northern Ireland (WeBS: Frost et al. 2020).
|UK breeding population
|+234% increase (1995–2020)
|UK winter population
|+73% increase (1995/96 to 2020/21)
The winter distribution of Gadwall is wider than in the breeding season due to dispersal from natal areas and the arrival of migrants from Iceland, the Netherlands, Scandinavia and central Europe. This is particularly evident in southwest England, coastal Wales and Ireland, and Shetland.
Occupied 10-km squares in UK
|No. occupied in breeding season
|% occupied in breeding season
|No. occupied in winter
|% occupied in winter
European Distribution Map
From the former strongholds in East Anglia, Fife and Lough Neagh recorded during the 1968–72 Breeding Atlas, the breeding range of Gadwall has expanded throughout much of the lowlands of central, eastern and northwest England, eastern Scotland, Orkney and the Uists.
Change in occupied 10-km squares in the UK
|% change in range in breeding season (1968–72 to 2008–11)
|% change in range in winter (1981–84 to 2007–11)
Information about movement and migration based on online bird portals (e.g. BirdTrack), Ringing schemes and tracking studies.
Lifecycle and body size information about Gadwall, including statistics on nesting, eggs and lifespan based on BTO ringing and nest recording data.
|Number of Broods
|55×39 mm Weight = 44 g (of which 8% is shell)
View number ringed each year in the Online Ringing Report
|Maximum Age from Ringing
|21 years 3 months 29 days (set in 1986)
|4 years with breeding typically at 1 year
|0.72 (Male: 0.752±0.054 Female: 0.69±0.065)
|264.3±10.3 | Range 247–280mm, N=198
|254.1±13.9 | Range 231-271mm, N=29
|271.7±6.9 | Range 260–284mm, N=106
|255.7±6.1 | Range 245–265mm, N=91
|810±105 | Range 650–980g, N=183
|749±90.2146 | Range 610–920g, N=29
|840±98.22 | Range 675–990g, N=95
|778±103.2 | Range 630–980g, N=87
Feather measurements and photos on featherbase
|2-letter: GA | 5-letter code: GADWA | Euring: 1820
For information in another language (where available) click on a linked name
Interpretation and scientific publications about Gadwall from BTO scientists.
Causes of change
There is little good evidence available regarding the drivers of the breeding population increase in this species in the UK.
Further information on causes of change
No further information is available.
Information about conservation actions
Many of the current breeding populations probably descended from released birds, although the species is a native breeder in Scotland and it is unclear whether any of the introduced breeding populations have been joined by wild birds. As an increasing species, no specific conservation actions are currently required for Gadwall, although actions to maintain and create wetland habitats and to provide nesting sites for other wildfowl are also likely to support this species.
Links to more information from ConservationEvidence.com
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