Argentine football club River Plate announced some unusual new signings on Saturday – two sparrow hawks brought in to frighten other birds away from the club’s newly laid playing surface.

The Buenos Aires club returned to its Monumental stadium last month after a seven-month refurbishment, costing a reported 200 million peso ($2.20 million), that included laying a brand new pitch.

The hawks were introduced after pigeons ate grass seeds, compromising the ground where the Argentina national team play many of its home games and where it won its first World Cup trophy in 1978, the club told Reuters.

Local media showed videos of the hawks being let loose and flying across the pitch.

River takes on its archrivals Boca Juniors in a league clash away from home on Sunday.

Hawks are widely used to protect airports and sports grounds, including golf courses, to keep away other smaller bird species and harmful insects.