More Monarch caterpillars found

There are three caterpillars that I've found, and since they're kind of hard to find, more could be found. And they don't stay put - one night they'll be on one milkweed, so I mark that one with a stake so I can easily find the caterpillar later. Then I come back a day or two later and look for the critter, and it's moved to a completely different plant. Don't know why they do that.

The little guy to the right is the smallest; originally it was up on the leaves of a full-grown plant, then the next day when I returned, it was on a very small, juvenile milkweed plant. I don't know if it fell from the higher plant, or if the leaves of the larger, older milkweed were too tough for a new, young caterpillar, so it voluntarily moved.

The caterpillar to the left is one of the two bigger ones. Last night when I went out to look for all three of them, I was only able to find two. They can be difficult to spot since they generally stay on the underside of the leaves. I suspect, too, that a bird would be excited about finding one of these tasty morsels.