I'm not at all surprised, Karyn! Deer and rabbits not only eat butterfly host plants, they undoubtedly eat a lot of butterfly eggs/caterillars when they browse. They'll eat most anything! I let some American ladies stay on the host plant - cudweed - earlier this spring, and deer or rabbits ate the cudweed down to the nubs.
When I first moved to the country, all the deer hunters bothered me. Now I say, right on!
Sherry

It is my understanding, too, that during a drought, deer will eat plants they normally wouldn't touch due to the decline in their preferred food plants.

Is there a drought in the area where the BCs region?

Susan

In my area, we actually had more rain than usual. For whatever reason, the deer have decided my common milkweed is one of their hostplants this year.

Karyn, Sorry to hear about the deer making the BC population decline. When I planted Chelone lyonii here, I thought of the possibility of deer eating it and the cats on it (if I ever got any, which I haven't), but they haven't touched it. We have four regularly come into our backyard, but they mostly just eat the grass. There was one here just last week eating some of the jewelweed that is down by our stream. It was there for the longest time chomping away. I don't mind if they eat that, as it is very plentiful. I love to see the deer in the backyard, but I also know that they can be detrimental to the environment.
Cathy

No drought conditions here but the deer eat everything. They even eat my daturas and castor though they haven't gone after the milkweed.....yet. I never thought about the impact they have on the butterfly population and insects in general until I heard that report. At least the deer can't get into the backyard and that's where my butterfly garden is.

Sherry I used to feel the same way. I was such a bambi lover. Now we allow friends to hunt on our property with bow & arrow, no guns. We have an electrified fence at the farm but can't use that at home, besides that it would look terrible and the neighbors would have a fit.

We do have fun with the deer at the farm. They love peanut butter so we spread it on aluminum pie plates and attach the plates to the live wire. The deer can't help themselves and keep going back for more and getting zapped. It's like watching a Simpson's episode. lol

I have deer eating all my violets & hollyhocks this year. They also have grazed on my hostas & even my Partridge Pea plants. I think it is because of the drought we're having!!!
I used to grow annual pansies in the winter & the deer loved them...they would eat them to the ground! I heard to put human hair around the plants to prevent the deer from eating it...tried it on my pansies & it worked! When I get my hair cut, I ask my stylist to give me all of her cut hair she has swept up & take it home & scatter it around the plants I want to protect. It works on lower foliage but probably wouldn't work on taller growing plants.
They ate all my yellow indigo this year, also & even dug up the roots...I wish I had more seed but didn't realize they were after it until it was too late!

Deer are the big problem. ATVs are a small issue, in that some people like to go mudding, but they tend to make one rut and stick to it. Deer, OTOH, are hungry. Turtlehead is on the menu. 'Nuff said.

Now, my friends go deer-hunting by car. Whatever leaps in the way, gets clobbered. Not so nice for Hondas, but 18 wheelers make a very, very impressive pink deer mist.

Pink deer mist..... I LOVE IT!!!!!

Thr deer and bunnies are my enemy. Even DH said if he saw a deer in our yard he would shoot it! (It's not hunting season, but they are eating all of his mimosa trees.)

I'm so proud of him!

Betty

Turtlehead is the one plant that the deer never touch in my yard. Unfortunately I also don't have any baltimore checkerspots.