Helicopters can be funny because it's like the wild west with them often easily with the 0-400' AGL range where drones live. We have a lot of helicopter traffic at the beach where I fly. Lots of Coast Guard choppers, but also others. I sometimes instinctively drop altitude, but I sometimes just stay stationary if I can determine that it's obviously 100% nowhere near a collision risk. The other thing to be aware of is if there is anything obstructing your view of oncoming low altitude air traffic. I was flying a quarter mile north of a pier when a Coast Guard chopper suddenly appeared just past the end of the pier.
Get this though: I saw a private helicopter flying incredibly low when I was out surfing there yesterday -- under 50' AGL, maybe around 30-40' AGL. It was low enough that the passenger and I made eye contact as they flew directly over me. That one would have been hairy with a drone for sure!