New Species of Bird

Several months ago, I put up a bird feeder in our backyard.  I mainly wanted to entertain the kitties, but it was spring and why not feed the birds (it's only tuppence a bag).  I covered all the bases and put up a finch feeder, a hummingbird feeder, a suet block, and a general "wild bird" feeder.  Well, since then, there has been a very fat something eating the wild bird seed very quickly.  I always thought we had a family of squirrels or raccoons eating in our backyard-- you know, the usual bird feeder guests.  Then, the other day I come home and happen to look out the window and see who had really been visiting us!!

Now, my question is: are deer cute enough that I continue feeding it, or should I take steps to try to deter it from eating out of my bird feeder?