Honestly, bloody-curdling screams that go on for hours. I think there's a den in one of my neighbours gardens. I got up to watch them the other night because they were making such a racket. They can scale a 6ft + 2ft trellis fence like it's nothing. Playing in my neighbours paddling pool. Wouldn't be so bad if they only mated once a year but I think in the city they just breed all year round. Anyone else driven nuts by them?