George Christodoulou, a municipal employee, trains a Harris's hawk in Larissa, Greece, June 5, 2018. The Harris's hawk is particularly trained to chase away birds so that the city remains clean from bird droppings. (Xinhua/Apostolos Domalis)

George Christodoulou, a municipal employee, trains a Harris's hawk in Larissa, Greece, June 5, 2018. The Harris's hawk is particularly trained to chase away birds so that the city remains clean from bird droppings. (Xinhua/Apostolos Domalis)

George Christodoulou, a municipal employee, trains a Harris's hawk in Larissa, Greece, June 5, 2018. The Harris's hawk is particularly trained to chase away birds so that the city remains clean from bird droppings. (Xinhua/Apostolos Domalis)

George Christodoulou, a municipal employee, trains a Harris's hawk in Larissa, Greece, June 5, 2018. The Harris's hawk is particularly trained to chase away birds so that the city remains clean from bird droppings. (Xinhua/Apostolos Domalis)

A Harris's hawk is seen during its training in Larissa, Greece, June 5, 2018. The Harris's hawk is particularly trained to chase away birds so that the city remains clean from bird droppings. (Xinhua/Apostolos Domalis)