Learning a foreign language, the hard way

Communicating with Zip is a hit-and-miss affair. Sometimes I know exactly what he wants. But there are other times:

• On Sunday afternoon, my husband was napping in his chair when Zip woke him with a great fuss of alarming chirps and squawks. The tone was clearly understood: Something is very wrong! But it took some time to figure out that the something was my red, reflective-lensed sunglasses -- which had been sitting on the table facing him all day long, but had just become a problem.
  
  
• On Sunday evening, Zip was tucked away to sleep for the night. But about 10 p.m., he raises a ruckus, banging his food dish repeatedly with his beak. After a while he gives up and flaps his wings wildly in place, then goes back to sleep. The next morning, I discover that he has either eaten or thrown out almost all the food in his dish. Was this before or after the banging? Was the banging to signal he wanted more food? Or that he disliked the food he had?