I have been able to hide antibiotics in food, but you MUST track how much you put in, and not put too much into a large batch of food, as they must eat it all. In the past, Nilla wafer minis have served me well (and yes-- they are not healthy...but it was a matter of NEEDING to get the meds in and I didn't have a second set of hands, so that was what I did.).Note: This method is subject to waste, so you will need to ask your vet ahead of time in case they will be unwilling to provide you with added meds (in the event that yours gets tossed to the cage floor). It is essential that you know how much you have given your bird in order to complete the antibiotic course.
Never mix meds in with more food than they will eat, as it will make it impossible for you to know what they consumed and there will be so much waste. I found that giving the doses gradually (across a few different, small but novel ) foods, made it easier to ensure that it was all consumed and it allowed me to monitor dosing better as well. Plain oatmeal mixed with mashed bananas is another possibility for hiding meds, but remember, the medicine does have a flavor, and so hiding that will be the difference between success and failure. Sweet potatoes (cooked and mashed) can also hide things well, but again, keep the amount of food small so that you can track how much medication was actually ingested.
Toweling is the other option. If I could do that as a single person, I would because it is nice to get it over with, but it also stresses me out to think I might shove the syringe in the wrong part of her mouth...so I am pretty passive but meticulous when giving meds.