I refer to the letter from E. H. Saas headlined, 'Leave pigeons alone' (South China Morning Post, December 13), and would like to respond to the points made, since any argument for the rights of humans and animals to freedom must necessarily be qualified.

It is my understanding that all faeces, whatever its source, causes disease - that is why we are urged to wash our hands after visiting the toilet. However, having humans and pet animals produce faeces in a (hopefully) controlled manner in our homes is not quite the same as faeces being either dropped on us and our property by pigeons, or having faeces deposited on the pavements where we walk (by dogs).

As E. H. Saas says, dogs and rats can cause rabies, and so the Government tries to control them. Such animals kept as pets are presumably not carriers of rabies. The pigeons flying around where I live are under no such control - they nest in the air-conditioner spaces, where the smell and particles of their deposits are drawn into our homes.