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Are monarch butterflies poisonous to birds?

Are monarch butterflies poisonous to birds? Topic: Main sections of a research report
July 17, 2019 / By Bonny
Question: I saw a raptor dive down on a monarch and bye bye monarch. But I've been told that monarchs are poisnous for birds. Do any of you know for sure? The raptor, a kite, seemed to be fine.
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Best Answers: Are monarch butterflies poisonous to birds?

Alberta Alberta | 6 days ago
Monarchs have an effective chemical defense. When they eat milkweed, they sequester the poisonous cardenolides (also called cardiac glycosides) in the milkweed. Cardenolides are poisonous to vertebrates (although maybe not to invertebrates, bacteria, and viruses), and most Monarchs face little predation from frogs, lizards, mice, birds, and other species with backbones. But being poisonous doesn't help the Monarchs after a predator has already killed and tried to eat them. Monarchs need some way to warn off predators before they become lunch. Monarchs do this through their warning coloration, or bright colors (yellow, orange, black, and white). This coloration warns potential predators that the animal contains poisonous chemicals. Warning coloration may work particularly well in adult butterflies because the hard body and wings allows a predator to bite the adult, taste the poison, and release the butterfly without killing it. It is common to see butterflies with beak-sized sections gone from their wings. Large wings help the butterfly escape relatively unharmed. Since Monarch wings contain distasteful cardenolides, one bite may discourage further attack without killing the adult. Early studies of Monarchs showed that when a blue jay ate a Monarch butterfly, it vomited shortly afterwards due to the cardenolides. That bird also learned to never eat another Monarch butterfly. Like this early study, most research about Monarch predation has focused on bird predation, especially on adults, and researchers have found a few species that eat Monarchs despite the cardenolides. Bird Predators In the mid-1970s, scientists discovered Monarch overwintering roosts in Mexico. As they began to study these roosts, they found extraordinarily high mortality due to predation. Although researchers had reported some predation in California Monarch roosts before this, such high levels of predation spurred a number of studies investigating the species that preyed upon the Monarchs, ways those species avoided poisoning, the patterns of predation, and the impact of predation on Monarch populations. Although many birds live in the same area as the Mexican roosts, only a few feed heavily on Monarchs. Of 37 bird species reported in the region, 25 never feed on Monarchs while another eight only rarely eat a Monarch. Two species, Scott's oriole and Stellar's jay, occasionally hunt Monarchs, which means that small numbers of birds visit the roosts irregularly to feed on Monarchs. The two remaining species, black-headed grosbeaks and black-backed orioles, are the main Monarch predators. These two species feed twice daily at the roosts in mixed flocks of five to at least 60 birds and annually consume several million Monarchs in the Mexican roosts. Black-headed grosbeaks and black-backed orioles have very different ways of avoiding poisoning when they eat Monarchs. Grosbeaks, which eat the entire Monarch abdomen, are relatively insensitive to cardenolides and can tolerate moderate levels of these chemicals in their digestive tract. Orioles, on the other hand, vomit after consuming much smaller amounts of cardenolides. They avoid poisoning by not eating the cuticle, which is where Monarchs store cardenolides. Orioles slit open the body and strip out the soft insides. Oriole and grosbeak predation follows several patterns. For example, grosbeaks eat fewer female Monarchs than orioles. Female Monarchs have, on average, 30% higher cardenolide concentrations than males. Females, therefore, may be more toxic than males. Since orioles avoid the cardenolide-laden cuticle, increasing concentrations may not affect them. On the other hand, females also contain more lipids (fats) than males and therefore may provide more nutrients per prey item than males. Scientists still have not determined the relative important of these two different forces (avoiding poisons and obtaining nutrients).
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Alberta Originally Answered: Has anyone had any luck getting orchardists to stop using m-80's or dynamite to scare away birds?
I know what you mean - I know someone who used to live across the street from a blueberry farm, and the noise was incredible - why she didn't haev PTSD I don't know... This is a question of who was there first, and whether you knew they did it when you bought your property, and something to research at your county or town hall...if the local laws allow it, then you're up a creek. It does seem iffy about them being able to set them off before 7AM, though -sooner or later, people need to be able to live in their house in peace and quiet, and not at the whims of the local industry. But money is power, and all those fruit baskets generate a lot - and if it's who I think it is, you may as well be up against the federal government. Start with local government, and go from there - you may have to go to court, and take your neighbors with you. With the power of the internet, you may have a class action suit.
Alberta Originally Answered: Has anyone had any luck getting orchardists to stop using m-80's or dynamite to scare away birds?
At first glance I bet it seems like a nice place to live. lol I can't believe they are using cherry bombs!!! Why on earth would they do this in the morning? Or the middle of the night!?! I can see why the dogs are barking. It is honestly best to just keep yoru dog inside. You have every right to complain. I bet it does feel like a war zone. I would be so upset. I've never had this problem, nor heard of this before. You need to move and keep your dog inside. Or, I suggest getting a bunch of people together and making a petition.
Alberta Originally Answered: Has anyone had any luck getting orchardists to stop using m-80's or dynamite to scare away birds?
Well, were they there first? I actually get annoyed when people move to the country, then complain about the farmers!!! The farmers need to scare away the birds, and this is how they do it - do you have any other suggestions for them?

Trevelyan Trevelyan
Yes. Raptors can make mistakes. If what you saw was a monarch, that kite could be in trouble. Even mimics would normally be safe from predators, but you must realize that the poison defense works on average. So, by what ever mechanism the the raptors use for avoidance, it is not foolproof and some raptors will be no ones ancestor.
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Trevelyan Originally Answered: Has anyone had any luck getting orchardists to stop using m-80's or dynamite to scare away birds?
I know what you mean - I know someone who used to live across the street from a blueberry farm, and the noise was incredible - why she didn't haev PTSD I don't know... This is a question of who was there first, and whether you knew they did it when you bought your property, and something to research at your county or town hall...if the local laws allow it, then you're up a creek. It does seem iffy about them being able to set them off before 7AM, though -sooner or later, people need to be able to live in their house in peace and quiet, and not at the whims of the local industry. But money is power, and all those fruit baskets generate a lot - and if it's who I think it is, you may as well be up against the federal government. Start with local government, and go from there - you may have to go to court, and take your neighbors with you. With the power of the internet, you may have a class action suit.
Trevelyan Originally Answered: Has anyone had any luck getting orchardists to stop using m-80's or dynamite to scare away birds?
At first glance I bet it seems like a nice place to live. lol I can't believe they are using cherry bombs!!! Why on earth would they do this in the morning? Or the middle of the night!?! I can see why the dogs are barking. It is honestly best to just keep yoru dog inside. You have every right to complain. I bet it does feel like a war zone. I would be so upset. I've never had this problem, nor heard of this before. You need to move and keep your dog inside. Or, I suggest getting a bunch of people together and making a petition.

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