Stamping is unique to flamingos, and not a foraging technique you see often in the Algarve as usually the birds walk slowly forwards with heads immersed, occasionally up-ending if in deep water. So I was delighted when we actually saw them stamping one day in Ludo and Lagoa de São Lourenço.
As they stamp and sink into the mud, the birds turn in a circle around their bills, gathering invertebrates/larvae buried in the mud or eating the mud they sieve from the centre of the circular depression they have created. If the water was to recede you would see saucer like depressions. Sometimes they don’t turn but simply ‘mark time’ as they stamp rapidly to stir up the mud and bring their prey into the muddy water. On this occasion as you can see from MrB’s video they seem to be doing both! Apologies by the way for the camera shake it was an incredibly windy day.
One of the most unexpected things I think about flamingos is their call. Before I heard it for the first time, I had envisaged a rather elegant sound given their appearance, but instead it is honk like a goose! And flamingos don’t just sound like geese they also graze, well almost. Flamingo grazing takes the form of filtering the water or mud in order to capture their invertebrate prey. Their unusual shaped bill contains a complex mechanism which enables them to filter organisms from mud and water. By opening the bill a few milimetres water is sucked in. The bill is then closed to enable the flamingo to filter the water by using its tongue; the water is expelled near the base of bill. They do something similar when they eat mud, but I am still trying to get my head around that!
I have also learnt that flamingo foraging behaviour varies depending on their feeding environment. The most common foraging behaviour to be observed in Portugal is the first one depicted in the Poyser diagram – walking and filtering. It is also not uncommon to see up-ending and even swimming as some of the lagoons are quite deep. The latter though always strikes me as odd! In winter when their normal food is in short supply, you are more likely to see them walking forwards with the head immersed and snaking side to side. By the way if you see one ‘running’ after its prey that you are indeed privileged as it is rare for any flamingo to seize prey in this fashion. It has been observed though, so you never know! The only reason I know any of this is because of my fascinating Greater Flamingo book, a Poyser Monograph, written by Alan Johnson and Frank Cézilly. Poyser monographs are superbly written and authoritative ornithology books, and well worth their price tag.