Pre-Panel & One Quick Question

Why do seabirds/shorebirds screech and land birds sing (what is to our ears) melodious notes? If Immigration NZ has the prerogative to refuse entry to anyone coming into this country, why can't it refuse entry to people who are NZ citizens by birth, have lived in Australia since a very young age and have no connection with NZ, but are being deported by the Australian Government for relatively minor crimes? What is flit?