I had exact same noise, a tink while I was out of the saddle torquing up hills. Lbs identified it as thefreewheel in my hub. They replaced, problem gon . They knew their stuff.

Why does my bike make a noise when I pedal hard?
I can't think of the word to describe it. Something similar to "wanderer" or "roamer". 

It's often used to describe people that don't stay in one place... not "migratory"...
