Don't Poo-Poo These Caterpillars

I had exhausted my options of what to call these very odd-looking caterpillars hanging onto the trunk and leaves of my potted orange tree on the deck as I was trying to identify them with an online search. I was about to brush them off orange tree leaves on my deck, thinking some bird had settled in the tree for the morning, when one of them moved his head and stuck out little red antenna. After several searches for brown caterpillars and caterpillars with red antenna, turns out these interesting-looking caterpillars, ranging in size from 1 to 2 inches, are know as bird-poop caterpillars and will soon become swallowtail butterflies! Another good reason not to use pesticides in the garden. Now I need to make sure I have enough good flowers in the garden they like to munch....