The invention relates to uses and methods relating to grass and endophyte combinations to repel avian species from the grass and endophyte combination. In particular, methods are described to select grass and endophyte combinations in order to enhance or maximise the repellent effect. Preferred endophyte and grass combinations are described which are based on the selection methods and include AR4, AR5, AR8 and AR94 (Deposit Nos. V07/029054, V07/029055, V07/029056, V07/029057) in Lolium cultivars as well as AR601, AR602, AR603, and AR604 (Deposit Nos. V07/029058, V07/029059, V07/029060, V07/029061) in Festuca cultivars.
