Originally from sub-Saharan Africa, this species has a well established and expanding population centered on Lisbon and the Tagus estuary. It is now established on the Sado as well and will doubtless move further south in the future. 

The male has stunning yellow and black plumage during the breeding season and his bill also changes colour from fawn to black at the same time. The female is an inconspicuous brown and can easily be mistaken for a Sparrow. 

They inhabit wetlands surrounding rivers and rice paddies, breed in reed beds and can attain large numbers.