More often than not ticks are hanging out on long grass waiting for you to brush up against it.

I believe it's a common (and unproven) myth[1] that 'falling from trees' is the primary way that ticks seek out targets...

1. http://medent.usyd.edu.au/fact/ticks.htm

Yeah ticks will really swell up on an animal that can't get rid of them. You see them on outdoor dogs sometimes too, they look like grapes they're so full of blood.