So I tossed out an avocado, as an experiment.
Initially the couple of deer who came over sniffed at the new offering gingerly and then turned back and attacked the apples. They didn't seem certain as to what was required to deal with the avocado. But later on one of the deer came back and nosed out the avocado from under the snow. There was a little wrinkling of the nose, rather like a two-year-old who's been given spinach for the first time and isn't sure that this is an experience that he/she might want to actually repeat - but it's STILL only 20F out there, and food is food, and the deer finally figured it out and ate the avocado. I didn't see what it did with the pit, which is admittedly rather larger than anything one might discover inside an apple - but it went, the avocado.
I suppose, standing hock-deep in snow with more threatening to come down any moment now, they'll take what they can get. They prefer the apples, the corn - the familiar - but sometimes food is food...
(BTW - new icon - specially for winter deer posts...)