Question of the Day: Are These Birds Toxic?

image from Reuters, pinched from the Sydney Morning Hereld
Monarch butterfly. Photo from Reuters, pinched from the Sydney Morning Herald

The burning question of the day popped up this morning while I was making coffee at 4 am (I’m a light sleeper) and listening to a BBC program on monarch butterfly migration. These beautiful North American butterflies are right now heading south along with all those feathered vertebrates to their wintering grounds in Mexico and parts of central California. My yard in Oklahoma is en route. A population of monarchs winter in the Monterey pines of Pacific Grove, California, and the sight of tree-covering clusters of orange-and-black butterflies bending down the branches is really something to see.

The key phrase here is “orange-and-black”. It’s a color scheme known as aposematic and is used as a warning to predators: their target may be toxic. Having fed on lovely but toxic milkweed when they were caterpillars, the adult butterflies taste bad and don’t get eaten too often, usually by mistake (and I’m picturing some young, inexperienced bird spitting and making a face- a nice image). I’ve always heard that nothing preyed regularly on them, but according to Chip Taylor, professor of entomology at University of Kansas and director of Monarch Watch, and Bill Calvert, an independent monarch biologist, there are three predators on the monarch’s Mexican wintering grounds, one species of mouse and two birds: the black-backed oriole and the black-headed grosbeak. What do these birds have in common (besides the word “black” in their names)? They are both black-and-orange.

Black-backed Oriole. Photo by Manuel Grosselet
Black-backed Oriole. Photo by Manuel Grosselet
Point Reyes Bird Observatory
Black-headed Grosbeak. Photo: Point Reyes Bird Observatory

Which led me to wonder: are these two species are eating monarch butterflies for toxic protection from their own predators? Are there any toxic birds out there, anyway? The answer is yes, one known case.

New Guinea Hooded Pitohui. Photo John Dumbacher
New Guinea Hooded Pitohui. Photo John Dumbacher

The New Guinea Pitohui (a name that sounds like what a predator does when spitting one out) is the only known example of a poisonous bird. It’s skin and feathers are toxic when eaten. It’s also black-and-orange. According to a recent study by the California Academy of Sciences, the pitohui may get its toxins by eating choresine beetles. Fascinating stuff. Further reading here and here.

So the question of the day is this: are black-backed orioles and black-headed grosbeaks toxic? Who wants to test this one out? And will someone please check on that mouse?

11 thoughts on “Question of the Day: Are These Birds Toxic?

  1. julie Zickefoose says:

    No comments yet??? I LOVE This Post!! Synthetic thinking, it’s the cornerstone of natural history. I have always wondered if most woodpeckers have aposematic coloration–I’m told they taste bad. With the exception of the pileated, which my neighbor ate and said were good–he called them wood hens.

    And toucans taste bad, too, and they have the black-white-red-combo AND blue skin.
    Ratels taste bad: black and white.
    Skunks, well, you know.

    There are a lot more toxic things out there than we know, and we mostly ignore the way they try to tell us with their coloration. We just think they’re pretty.

  2. lola says:

    You’re onto something there. I find it quite interesting as well that they could have some sort of protection because of their diet. I am unsure, however, that they actually do have protection or not. I just hope that my grade 7 monarch project turns out O.K. šŸ™‚

    Look below to see the crazily smart genius kid’s name…NOT! I luv usin ur midle name!

  3. lola says:

    me again! im so awesome i just wanted to say hopray for monarchs! Don’t kill them off! šŸ˜¦ Help out in any way that you can!!! šŸ™‚ šŸ™‚ šŸ™‚ šŸ™‚

  4. lola says:

    me again! im so awesome i just wanted to say hooray for monarchs! Don’t kill them off! šŸ˜¦ Help out in any way that you can!!! šŸ™‚ šŸ™‚ šŸ™‚ šŸ™‚

  5. Mike says:

    Now that lola (the commenter above) will let me get a word in edgewise, I just want to tell you how much I love this post. The black-and-orange connection is very cool. Could it be that only male orioles taste bad? I doubt it but the fact that coloration is variable across ages and sexes makes me wonder whether the plumage is intended to signal toxicity.

  6. zeladoniac says:

    I like the question- and note the resemblance between the three birds in markings as well as color. Is the coloration the result of sexual selection, mimicry, toxicity in adult males, or all three?

    This would make someone a nice thesis, and I know just the person to take it on. Lola- do you need another science project?

  7. Amelia says:

    Now here is a post I’ll be thinking about for a while, orange-black connections. I have been watching a monarch in my yard for last several days. I, of course, think it is the same solitary one I see each day. It seems to feeding mainly on my Mexican Sunflower (tithonia). It’s a bright orange flower, (no black) and I wonder if the butterfly thinks he’s in Mexico already. I’ve taken photos and have been thinking to do a painting of it some wintry day.

  8. Brian says:

    Thanks for the Okie take on digiscoping, I needed that.
    Where did you find that collapsible pochade(?) box tripod, and do all canon powershot models work with this set up, or just one kind?

  9. zeladoniac says:

    Hi Brian- the pochade box tripod came from EasyL, at and their pochade boxes are wonderful, too. It’s a ball-head style tripod mount with a quick-release. I think it would fall over with a heavier scope but it’s perfectly fine with the lightweight Nikon. As to the variety of cameras the connector will work with, the answer is unkown, since I’ve only used it with mine šŸ™‚ but it’s easy enough to try it out- let me know if it works with yours.

    Amelia- I LOVE tithonia. You remind me that I should look for some seeds of it for next spring. Have fun painting!

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