How can I check if Warren Buffett or Berkshire Hathaway is parking cash more than usual?

according to a poll by UBS Global Wealth Management.

Hello, I'm Warren Buffett and some UBS GWM asked ME, in poll, if I think that it's good time to invest or to wait. Because I want to make money I will say to them that I'll wait while I invest so whoever listens to them will buy from me.

And any other combination of possible answers.

And obligatory Dilbert comic :

Updated version for 2013:

As @DumbCoder coder suggested, filed annual reports is the only real public information you have, but this is at a point in time, and may be arbitrarily abnormal; for tax reasons.

You also have public statements, like the one you saw. These are again at a point in time, and there may be ulterior motives for these — both from Warren Buffett and the news reporter. So biases will exist.

The information you are wanting is probably needed on a daily or weekly basis, since you want to engage with the market as quickly as Berkshire Hathaway do.

This just isn't available.