Kite bird scarer

A neighbor has put a Hawk kite on their washing line to scare away birds from his cherry tree. I went and told him it would scare ALL the birds in the area and not just the birds visiting his garden.  Including nesting Herring Gulls on the roof of the house behind them. They took off at first and left the nest and the egg/eggs unprotected. They have now come back. Thankfully

Is he allowed to use this type of scarer in a domestic setting