Being small, round, fluffy, cute, and very vocal makes it easy to communicate preferences when you have them.
For instance, you can shriek. You can crunch things with your sharp beak. You can flap your wings and hang upside down (this is particularly effective in the evening – and around Halloween each year).
You can also leave a trail.
If the trail happens to contain tell-tale signs of the specific thing(s) you have a preference for, even better.
Here is an example.
Author: Shannon Cutts
Co-Author: Pearl Cutts