While some may question whether Xenophora, the shells that collect and arrange shells, are truly "Assemblage Artists of the Deep", as the Zymoglyphic Museum claims, bowerbirds can make a much stronger claim to the title of "artist". These birds live in the rain forests of New Guinea and northern Australia. Males use sticks to build bowers, which are staging areas for their collections of interesting objects. They arrange these objects in particular ways to entice females, who are the judges of quality, to mate. Their selection of objects has remarkable overlap with Zymoglyphic art - snail shells, bones, small skulls, moss, fungus, dead bugs, flowers, and the occasional interesting plastic figure. One bird was even found to collect skeletonized leaves! Each individual bird has his own style, often preferring, for example, that all objects in an arrangement be a particular color, or a pair of colors.
David Attenborough has produced an excellent documentary on these birds. My favorite part is when he proves that the birds don't just collect these objects, but are are quite particular about the arrangement of them - he moves a few of the objects around when the bird is off somewhere, and when the bird comes back, it cocks its head quizzically at the disturbed objects and puts them back where it had them originally. There is also a sequence in which he compares the birds' elaborate stick bowers with a stick pile made by artist Andy Goldsworthy. You can see that clip here. The last part of the film shows the influence of the modern age on bowerbird art. In more urbanized settings, they collecting all manner of plastic toys and shiny things for their arrangements.
The documentary is available in the US as Nova - Flying Casanovas. In the UK, it is included on the BBC DVD "Attenborough in Paradise".
The photo above is from Animal Artisans