Mourning Cloak Butterfly

2011 December 24

And here is our annual Christmas butterfly[1] – in a bit better shape than the one from last year.
I’ve been stalking these for years, and I finally caught one. This one was flying around the feral apple trees in the back yard on August 14. I had to chase it all over the yard with the insect net, and it almost got away at the end, but I eventually snagged it when it landed in the tall grass.

It’s a Mourning Cloak, Nymphalis antiopa, a large, strong-flying butterfly that is nearly as big as a Monarch. That first photo with its wings open was really hard to get, because it would only flash the wings open briefly before either fluttering off, or slapping them back together again to look like this:


It looks rather a lot like a piece of lichen-encrusted bark or a dead, moldy leaf when it poses like that, which is one of the reasons it took a long time to catch one – they’re hard to see except when they are flying. We see them around quite a bit, they are generally the first butterflies we see in the spring, and the last ones we see in the fall. That’s because they overwinter as adults, nestling down in crevices of tree bark, cracks in buildings, and other somewhat protected spaces before letting themselves freeze solid. So, they fly out in the spring almost as soon as the sun thaws them out.

There aren’t many flowers first thing in the spring, so instead of drinking flower nectar they mostly go after other sugar sources, like tree sap. It’s not just maple trees that have a big rush of sap in the spring, most other hardwoods do it too, so there is a reasonable amount for them to eat. They lay eggs pretty early in the season on willow, birch, poplar, elm, and related trees, and the eggs hatch out into black, spiky caterpillars with orange spots running down their backs. The caterpillars mature fairly quickly, then pupate to emerge as adults around mid-summer. They then disperse across the countryside, and promptly estivate (the summer equivalent of hibernation) until late summer or early fall. They then eat what they can to fatten up for the winter, with a particular interest in fruit juices, tree saps, and the liquids from animal droppings (they are only occasionally found on flowers).

Mourning cloaks are in the same family (Nymphalidae) as a lot of other large, showy butterflies like the Monarchs, Viceroys, Admirals, Tortoiseshells, and Fritillaries, which are collectively known as “brush-footed butterflies”. I hadn’t realized previously what was meant by “brush-footed”, but while reading up on this one I found that the first pair of legs on the adults is reduced to a small brush-like structure, and they only stand on four legs when they rest:

It looks like nobody is quite sure what advantage, if any, they get from the reduced size of the front legs.

Anyway, one of the reasons for the dark, almost black color is that it helps them absorb sunlight in cold weather so that they can more quickly reach flying temperature. Which is really, really important in this climate.

And, aside from their unwillingness to hold still, it is really hard to get the exposure right for the whole wing. If the exposure is right to show detail in the dark part, then the gold trim ends up washed out.

Mourning Cloaks are found all over North America and most of Eurasia, and for once humans didn’t import them anywhere[2]. They are strong enough fliers and migrators that they did it themselves, sometime in the distant past. And the name is the English translation of the German, Swedish, and Norwegian names, who all thought these butterflies resembled the black cloaks commonly worn by people who were in mourning for the dead.

[1] If you do something once, it’s just a thing. But if you do it twice, it’s a tradition!

[2] Except maybe to Great Britain, where the common name is “Camberwell Beauty”, after some specimens that were discovered in Camberwell (part of South London) in 1748. They were believed to have been stowaways on Scandinavian lumber ships. These days, they occasionally migrate to Great Britain during the summers, but they don’t seem to have established a breeding population there. It is believed that they need cold winters, with a solid freeze and dry air, to overwinter successfully. The prolonged wet, hovering-around-freezing UK winters don’t allow them to hibernate properly.

4 Responses
  1. December 30, 2011

    Great shot with the wings open. That doesn’t look like your normal camera backdrop. Did you use a field camera to capture this?

  2. December 31, 2011

    I didn’t use a different camera for this one, but I probably should have; with the macro lens I normally use, I had to stand way back (about 3-4-feet), and still couldn’t get the whole wing into the picture (which is why the wings ended up a little clipped on the left).

    The backdrop is the inside of one of the collapsable mesh cages that I got from BioQuip. It has shown up as a backdrop a number of times in the past, but it looks rather different at the high magnifications that I normally work at. I think you’re right – it makes a much nicer backdrop at low magnification like this, when there isn’t so much contrast between the blazing white screen fibers, and the dark holes.

  3. January 7, 2012

    I wasn’t complaining at all. Splendid shots! It would be interesting to see a close-up of part of one wing, like the upper right hand corner. I wondered if you could see the dust or tiny hairs or structure of the wing with that photo. If you used your monster camera, then the wing photo looks like you reduced the resolution considerably and you might be able to post a tiny detailed insert.

  4. July 22, 2014

    I took a picture of one of these last year in Colorado and i have been looking for info ever since. Thanks for the awesome update!

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