July 28, 2008

The Thistle Dilemma

Butterflies on musk thistle (Carduus nutans)

Here are the butterflies sipping nectar from a thistle. Happy happy butterflies. Everyone likes butterflies.

But the musk thistle is declared to be a noxious weed almost everywhere, including Custer County, Colorado. Bad bad thistle--it sometimes takes over pastures, particularly over-grazed pastures.

And every summer there is a "spray the noxious weeds" program. M. goes ballistic at the idea of anyone spraying anything anywhere near our place, and I am not too keen on it myself.

The last time I saw county spraying in action, it was one guy driving a flatbed truck down the road with a sprayer mounted on the bed. He steered with his right hand, while waving the spray wand wildly up and over the cab with his left.

Not exactly what you would call "targeted application." I could smell the spray 100 yards away.

So I try to control thistles mechanically, in the hopes that I don't give anyone a reason for spraying here. Alas, poor butterflies.

Anyone want to identify the butterflies? Some kind of fritillaries? They look like the Variable Checkerspots on this page to me.

UPDATE: In the comments, photographer Tom Whelan identifies it as a greater fritillary.


Anonymous said...

Well, I like butterflies, so it is sad to see the thistle they like being removed. On the other hand, if it chokes out other plants, it should be removed. Hopefully the butterflies can find something else they like as well.

TomW said...

Nice image, great perch.

It's a greater fritillary and not a checkerspot. In the mountains in the west there are a pile of similar species (Great Spangled, Calippe, Zerene...) and you need all the underside markings and upperside markings to tell them apart.

Chas S. Clifton said...

Thanks, Tom. I know most of the local birds, but only a couple of the butterflies.