I think many birds will gladly eat them while they're smallish. Once they get large, it's probably only the more dedicated insectivores that will go for them. Like cardinals. Here's video of a cardinal eating a similar sized caterpillar that could be a hornworm. https://www.youtube.com/watch?v=ktWIEnqKK34 (Warning: the video is a little gross, as the bird really mangles the caterpillar). I haven't personally seen cardinals in the act of eating a hornworm, but something must be doing so because I only find about 2 a year, but I see the moths in my yard. And cardinals do like to nest in my neighbor's hawthorn bush and use my garden as an insect larder.

There are half a dozen subspecies of American robin. The ones from Newfoundland are sometimes called "black-backed robins", and in addition to being much darker than the more common subspecies are somewhat larger. Birds from the rain forests of the pacific Northwest are also very dark. Probably what you saw was an adult male bird from one of those subspecies.

It's not a wren. My wren says "kiddeo kiddeo kiddeo." I listened to wrens' sounds online and it wasn't there. My wrens appear in plain view for me. Love them. Flibbidy jibbit is exactly what the bird says! It repeats it about 8 times and stops. It's always from high in the trees. I looked up the vireo's song and it isn't that. I've never seen a vireo where I live. Thank you both. I'm still trying to figure this out.

beautiful! I would guess snowy egret, does it have yellow feet?