Caterpillars in the yard

When I walked outside this morning I noticed one big caterpillar that I determined was a Monarch butterfly caterpillar on the butterfly weed, asclepias.   Then I looked closer and found another large one and two tiny ones, less than an inch.  But looking under the leaves I noticed a very tiny, no bigger than a large pin head, something that I think is a just hatched.  

I got in touch with our Blipfoto  monarch butterfly expert about creating a place to put the caterpillars so I could be sure to see the next two stages of the life cycle, the pupa or chrysalis and the emerging butterfly.   After some debate with myself, I decided to just let the caterpillars stay where they were.    My butterfly weed is in the process of turning yellow and dying so decided the cats knew better how to take care of themselves than I did. The one stalk where I saw the biggest caterpillar is completely stripped of leaves so I broke off the stem he was on and moved it to a better stalk.   He was chowing down when I went out to look a few minutes ago.   Unfortunately, I did not see the second larger caterpillar who was very close to where this one was.   I did not see any wasps or other bugs that could eat him but maybe a bird came by.

So I will be watching every day.   Maybe more eggs will crack open and make caterpillers.   I have some plants in the front yard but did not see anything on them yet but I will be watching those too.  

Nature is so amazing!