Afghanistan (NB) (P), Albania (B) (NB), Algeria (B), Armenia (B) (NB), Austria (B) (NB) (P), Azerbaijan (B) (NB), Bahamas, Bahrain, Bangladesh (NB), Belarus (B) (NB), Belgium (B) (NB) (P), Bermuda, Bhutan, Bosnia and Herzegovina (B), Bulgaria (B) (NB), Canada (B) (P), Cayman Islands, China (mainland), Croatia (Local Name: Hrvatska) (B) (NB) (P), Cuba, Cyprus (NB), Czech Republic (B) (NB) (P), Denmark (B) (NB) (P), Egypt, Eritrea, Estonia (B) (NB) (P), Ethiopia, Finland (B) (P), France (B) (NB) (P), Germany (B) (NB) (P), Greece (B) (NB), Guam (NB), Haiti, Hong Kong (China), Hungary (B) (NB) (P), Iceland (B) (NB), India, Iran [Islamic Republic of] (NB), Iraq (NB), Ireland (B) (NB), Israel, Italy (B) (NB) (P), Japan, Jordan (NB), Kazakhstan (B), Kenya, Kiribati (E) (B), Kuwait, Kyrgyzstan (B) (NB), Latvia (B) (NB), Lebanon, Libyan Arab Jamahiriya, Liechtenstein, Lithuania (B) (NB) (P), Luxembourg (B) (NB), Macedonia [The Former Yugoslav Republic of] (B) (NB), Malaysia, Malta, Mexico, Moldova [Republic of] (B) (NB) (P), Mongolia (B), Montenegro (B) (NB), Morocco, Myanmar, Nepal, Netherlands Antilles (B) (NB), North Korea, Northern Mariana Islands (NB), Norway (B), Oman, Pakistan, Philippines, Poland (B) (NB) (P), Portugal (B) (NB), Puerto Rico, Qatar, Romania (B) (NB) (P), Russia (Asian) (B), Russia (Central Asian) (B) (P), Russia (European) (B) (P), Saudi Arabia, Senegal, Serbia (B) (NB), Singapore, Slovakia (Slovak Republic) (B) (NB) (P), Slovenia (B) (NB), South Korea, Spain (B) (NB), Sri Lanka, Sudan, Sweden (B) (NB) (P), Switzerland (B) (NB), Syrian Arab Republic, Taiwan (China), Tajikistan (B), Tanzania [United Republic of], Thailand, Tunisia (NB), Turkey (B) (NB), Turkmenistan, Turks and Caicos Islands, Ukraine (B) (NB) (P), United Arab Emirates, United Kingdom (B) (NB), USA (B), Uzbekistan, Vietnam, Yemen.
Vagrant to Cameroon, Congo [The Democratic Republic of the], Gibraltar, Greenland, Jamaica, Mali, Niger, Nigeria, Somalia, St Pierre and Miquelon (NB).
Unknown to Marshall Islands.
Widespread over great part of Palearctic and Nearctic Regions.
 
Population
Estimated population is 3,200,000 - 3,800,000 (2010).
Gadwall (Mareca) [XC848182]
by SonoNatura from Tacumshin Lake (East End), County Wexford, Ireland (call, flight call)
Gadwall (Mareca strepera) [XC845777]
by Paul Kelly from As Pozas, O Freixo, Sanxenxo, Galicia, Spain (call, courtship calls)
Nest
On the ground beside water.
Eggs (Guide)
Usually 8 - 12; pale yellowish-buff; ellipsoidal. Incubation: about 28 days; by male. Color is similar to that of the Eurasian Wigeon (Mareca penelope).
Subspecies
Subspecies couesi, Coues' Gadwall, described from Washington and New York Is, central Pacific, apparently not seen after its discovery in 1874 and considered extinct.
The following 2 subspecies are recognised:
strepera (Linnaeus, 1758) - Widespread over great part of Palearctic and Nearctic Regions.
couesi! (Streets, 1876) - Tabuaeran Is. (Kiribati). Extinct.
The Reader's Digest Book of British Birds 1980, 3rd Edition, Drive Publications Ltd ISBN 0 340 25308 8
Birds in Colour Campbell, B., 1960, Penguin Books Ltd
The Pocket Guide to Nest and Eggs Fitter, R.S.R., 1954, Collins
RSPB Handbook of British Birds Holden, P., Cleeves, T., 2002, A & C Black ISBN 0 7136 5713 8
Birds of Britain and Europe Sterry, P., et al., 2001, AA Publishing ISBN 0 7495 3068 5
The Popular Handbook of British Birds Hollom, P.A.D., 1973, H.F. & G. Witherby Ltd ISBN 0 85493 002 7