In this book ...Nature is as important to children as food and sleep....the message is about the connection to nature and the crucial part it plays in develop(ment)....for a generation of todays children the pleasures of free-range childhood are missing and their indoor habits contribute to epidemic obesity attention-deficit disorder, isolation and childhood depression....SAVING OUR CHILDREN FROM NATURE-DEFICIT DISORDER. Atlantic Books London 2009 2010
'A cri de coeur for our children'... Margaret Stead, Guardian.

Nature and crisis....Song bird ownership, trading and competition is a large undertaking in Indonesia. Forest birds are endangered.  The forest goes silent.
The program, Earshot, on ABC Radio National, 11 Sep 2017, The Silent Forest, reveals more.  The program is available on media if you are brave enough.
I made an effort to be aware of bird life in Indonesia and while some were seen many a time it slipped my memory but no big numbers were there like in those instances where we have to use spikes to discourage them nesting on the front of city buildings or where they will literally steal food as you are about to take a bite. By and large, city birds are a different matter to wild birds.