Is it common practice to remove an author's name from a paper?
This seems to be a blatant attempt to take credit for your work - as far as I know, this is both not common, nor acceptable. To quote @JeffE "hell, no", or a polite variant, is the only response.

I would, politely but firmly, state that as you have done the research and the write-up, then you are the first author, perhaps offer to have them as a co-author, only if they have contributed something.

I would also consider having a quiet word with the head of the department about this.