Are we then looking for life in Australia?

Seriously, the Martians are there (they invaded Earth back in August, when Mars was so close, but we fought them off). They analyze our probes and crash or buggerup those which would discover them, and let the others land. I mean, look at the pictures -- YOU wouldn't live there and neither do the Martians. Their rationale is that we'll think we have a high failure rate on a planet with a surface that looks like an Australian pizza and we'll leave them alone.

And why, you ask, are they doing this? Simple -- they have their listening and viewing posts on Earth and they get such laughs and giggles out of us they don't want the show disturbed.