Ecology is a study of organisms at their home. Ecological study of an birds included various aspects like population, habitat selection, food and feeding, roosting and roosting behavior, breeding activities etc. out of the above in this book we discuss only two parameters i.e. population and habitat of the birds of family Threskiornithidae. In this book we try to cover all the aspect of population and habitat selection for various proposes. The family Threskiornithidae is divided into two natural groups, the ibises with long thin and strongly down curved bill and the spoonbills whose bills are broad and flat. All the family members are gregarious and feeding in flocks. We used many references to make this book effective which are given in the last chapter This book included 10 chapters out of 10 chapter no. 1 to 5 written by Dr. Chirag A. Acharya and rest 05 (Chapter No. 6 to 10) written by Dr. Rajesh C. Senma.