Image from Google Images
Our skies have been besieged by these guys - sulphur-crested cockatoos. A native of Australia, they have an unusual, screeching call. They eat the acorn-like nuts that are in the plane trees that line our streets and at about this time of year - when the nuts are just right, presumably - they descend en masse. There are probably 200 in the trees surrounding our house right now. And when they're not screeching all you hear is a determined crunch, crunch, crunch of nuts.
PS I've posted this pic in preference to one of my own - every time I got near them, they all flew away!