As we all know, to blur out a zoo fence you need a telephoto lens and large aperture. The problem sometimes is that when you are zoomed in, you only get part of the animal. But when you zoom back to get the whole animal, then the fence shows up. Here is one solution. I zoomed in (200mm wide open with a 70-200 2.
and did a series of three vertical shots. Start at the head and work my way down, with manual focus and manual exposure. Then put them in the panorama builder in Photoshop Elements 9 and there you have it! (Just a few minor tweaks afterwards, including Tonal Contrast in Nik Color Efex 4).
Canon 5d2, 70-200 2.8L (non IS), great hornbill, Reid Park Zoo (Tucson, USA)