Hawks lined the nest with plastic bags

According to a study, plastic lining plays a role in warning other birds that the owner of this nest is ready to fight .

The nest of an 11-year-old hawk.
(Photo: Discovery News)

Hawks are carnivorous birds that are found throughout Europe and Asia. The females and males work together and line the nest with a white plastic bag before the female lays eggs.

To find out, this expert Fabrizio Sergio, of the National Scientific Research Committee in Seville (Spain), and his colleagues observed a hawk population in the Doñana National Park , Spain. . This population has been followed for decades and researchers have documented the age of most of these birds.

First, the researchers recorded the level of ' decoration ' in the 127 nest of this bird. They found that 77% of the nest was decorated and supplemented in 20 days before the birds lay eggs. Both females and males pick up plastic bags, and only choose white. Birds from 7 - 12 years old, their most prolific age, have the most majestic decorated nest. Very young or older birds decorate very little, according to Discovery New .

Hawks are still competing for aerial territory, injuring each other with their sharp claws. Those battles are not for the weak. According to the researchers, nesting birds with white plastic bags are often more successful in fighting invading enemies and are generally less vulnerable to attack. These birds always win when competing for food, so their offspring have a higher survival rate.