Relax. HK is a safe place.
I have never heard birdwatchers in HK are victims of robbery. Not an issue in HK, probably thieves are too lazy and don't go and hike in countryside. Also targets (the occurrence of birdwatchers) are unpredictable in countryside.
But in other places, it is a problem. I have given up visiting a mountain forest nr Kathmandu, Nepal after listened to local advice.