Despite the comments, I have a very hard time believing that it is CGI. To do this kind of work requires 3D computer software at over $1,000 to create and animate the duck, another piece of software at over $1,000 to do the digital editing, a very powerful computer, one heck of a lot of knowledge and technical skill in the area, some artistic talent and one considerable amount of time to put it all together. This is definitely not something that any average computer type could even attempt.
To be up-to-date the creation software is $3,500 and the video editing software is $5,000.
Err have you heard of software piracy? The worth of a package does not bar someone from using it. Neither does ram requirements. There are plenty of commercial software packages used by movie studios which you wouldn't dream of using on a machine with less than 8gb of ram, er if you're making a commercial movie. But the graphics what you see here could easily be done on 3d studio max R6 or even 5. (current version is 9). I remember playing around with 3dsmax R3 using camera motion capture to put a 3d object in a filmed scene on a P200 MMX with 128mb of ram. The final 12 seconds of footage took about 3 days to render.
/EDIT: I'm not arguing about it being fake or not just pointing out there's no real barrier to doing it in CG, especially given the crap video quality youtube offers.