eye contact

I try to say hello or, at the very least, acknowledge people who are walking towards me with a smile or a gentle nod of recognition, especially here at the field station. I've found that the foreign researchers always greet you back. Most of the locals, on the other hand, tend to avoid eye contact. They either  look away at the last minute or not acknowledge the greeting at all. I think it might be cultural. Perhaps I need to change my brash Australian ways. The locals must think I am creepy.