Another example that many people have probably heard about is the crows in Australia who like nuts (see video below). The problem for the crows is getting the nuts open - they cannot do it themselves so instead they have developed a very clever strategy to achieve their goal. They fly to an intersection with traffic-lights and then wait until the cars stop (red light on), at this point they place their nut in their intersection and then fly up to a light-post of wire and wait for the cars to start driving. The cars then crack the nut and next time when the traffic light are red the crows fly down to the road and get their reward. Very clever indeed!
A third example that I only heard about yesterday, even though it was in our own Capital (Stockholm), is the doves who commute to work. In Stockholm there is a train network which is partially below ground and partially above. Doves have regularly been seen to board these trains, drive one station and then exit the train again. It seems that their rendezvous is "Farsta Strand" where there is plenty of cafes and restaurants where they find their food. The doves typically fly home however, sometimes they commute back from their work as well.
In some of the articles writing about this they say that the doves in London are even cleveler... They sometimes travel more than one stop.... My guess is that these behaviors (maybe with the exception of the chimp) are all extreme cases of operant conditioning. For some unlikely reasons the birds more or less accidentally dropped a nut or entered a train and then received a significant reward (either a nut or a lot of saved energy), which increased the likelihood that the behavior would occur again.