Hi SunTracker,
I once picked up close to a dozen in one day of playing in a field in Nova Scotia.
The advice regarding covering yourself in DEET is good. I use Deep Woods Off (the unscented version) and that works very well. DEET can also be used for getting them off. Spray the little buggers with it in situ and they'll let go in a jiffy, no head, no squeezing, no rumaging for the tweezers.
As far as advice for avoiding them. Avoid leaf piles and walking through standing grass above ankle height. When you come in from areas they are likely to be, take off your outer clothing and then check that first (that's where they start the climb) also, run your hand through your hair every now and then while you are outside (course for some of us, that becomes less time consuming every year).
- SEAGOON