I can see where you are coming from here, in so far as birds are meant to fly, and taking that ability from them irreversibly seems cruel.
IMO it's unethical, given the availability of reversible practices and netting of modern aviaries.
As far as flamingos -
here is an interesting NY Times article on one that escaped from a zoo and is surviving in the wild.
It might help? answer your question about pinioning:
"Scott Newland, the curator of birds at the zoo, said if the birds had arrived as newborns, they would have been kept flightless by essentially amputating a part of the wing in which they had not yet developed sensation, before the bone was formed. But the birds came to the zoo as adults, probably around 3 years old, and the institution considered the practice unethical for birds of their age.
Instead, adult birds are kept grounded by feather clipping, which Mr. Newland called “no different than you or I getting a haircut.”
I get the impression from
other recent articles that the common practice is on its way out; it's gotten more attention in the UK and Europe.
Eg: "Roger Sweeney, General Curator of North Carolina Zoo told us “
While pinioning is still widely practiced in the USA by the private waterfowl collections, zoos are moving towards discouraging the practice…The AZA encourages zoos towards using reversible methods of flight restriction and advise their members should develop a written policy on if, when, and how flight restriction is employed.”
It appears to be the AZA recommendation
since 2013.
