In my experience, they tend to move through the whole pile.
Renais

Welcome to the forum Harry.

If you seed your compost pile with wigglers, they will likely venture through the entire pile, as long as it does not dry out too much. You may or may not see them again.
Once worms are well established, If you maintain your pile as a " cold compost" pile and continually add materials, then the squirm will stay closer to the surface. That is, they will stay up as long as there is food and the bed is damp, dark, not too hot, not too cold, and protected. from predators.

What is your goals? There are lots of considerations if you want to turn the compost pile into a working wormery.

Happy wormin' back to you and good luck!

Pete

Thanks for the quick response mendopete.
What I was thinking was why not speed up the composting through the winter months using some of the oodles of noodles(ie.redworms) from my two worm bins. Just wonder if they will work the whole pile and whether they will be interested in a diet consisting mainly of the partially composted leaves(mostly maple leaves)? Any thoughts?
Harry

"using some of the oodles of noodles(ie.redworms) from my two worm bins. "
Go for it! They should be perfectly happy in the pile. The "next generation" of worms you should see in the spring will be well adapted and should thrive in the compost. Just keep it damp and protected.

Good luck!