Compare those diadems with this Hun crown from NE China. I think we also talked about this particular piece in some other thread. The head of the falcon/buzzard/eagle is not fixed so when the wearer walked/rode it bobbed. Anyway it is very dissimilar even tho the diadem found at Kerch does have a bird on it.
So this is why Hunnic cauldrons became important. These can be found from the Korea to the Atlantic, all the way in Eurasia, and a typical item of the Huns. Some has a base/foot.