Wildlife Scientist Explains In a Fascinating Twitter Thread Why Some Crows Kill Each Other

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    Bird - Kaeli Swift, PhD Follow @corvidresearch I've been getting a lot of questions lately on the theme of "did I really just see crows killing another crow?!" so let me dedicate a quick thread to the topic. Kaeli Swift
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    Text - Kaeli Swift, PhD Follow @corvidresearch Let's cut to the chase right away: yes, crows sometimes kill each other. Look, crows are complicated. Yes they engage in behaviors that we find enducing of "awwws" like gently preening their mate, or bringing people "presents", or playing silly games. 10:31 am 29 May 2019 NO A NO NC INOT 76 Retweets 465 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch But at the end of they day they're also competitive & need to survive & will kill to do it. A Murder of Crow A Murder of Crow, a visual story of a crow apparently being executed by one of a group of crows, with plenty of help and encouragement. youtube.com 10:31 am 29 May 2019 NO A NO NO INOT 42 Retweets 333 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch There's 2 main reasons crows kill each other. The first is territory transgressions i.e. someone crossed a boundary they shouldn't have and got attacked by the pair (and whoever they recruited) 10:31 am 29 May 2019 57 Retweets 360 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch This is especially relevant at this time of year, when males will try and sneak on other territories to copulate with the female. So these kinds of lethal interactions seem to tick up right now. 10:31 am 29 May 2019 42 Retweets 315 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch The second is that, for reasons not entirely clear to us, crows will go after and kill already injured crows. This scenario is usually the hardest for people to swallow because it feels so entirely unfair. But sometimes, it's what they do. Even with juveniles. 10:31 am - 29 May 2019 Ma 54 Retweets 387 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch Maybe they do that because they're willing to take advantage of any opportunity to reduce competition, or maybe as a way to reduce predation of crows. We don't really know. 10:31 am 29 May 2019 AIY 38 Retweets 311 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch So yeah, it's a grisly part of their behavior. But it's also, on the whole, rare. And before any crow haters are tempted to weaponize this into a reason "crows are the worst" let's put this into broader context. 10:31 am 29 May 2019 30 Retweets 300 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch The reality is that tons of other animals also, sometimes or even regularly, kill members of their own species for a variety of reasons. 10:31 am - 29 May 2019 WALL 29 Retweets 305 Likes ento
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    Text - Kaeli Swift, PhD Follow @corvidresearch Many social primates with form coalitions and kill rival groups to reduce competition, or will kill more dominate individuals even from within their own groups. scholar.google.com/scholar? hl en& 10:31 am 29 May 2019 27 Retweets 269 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch And a quick google search reveals a whole grab bag of misc. observations of different kinds of animals killing their own, from pumas to wolves, to ground squirrels and tree swallows. 10:31 am - 29 May 2019 23 Retweets 230 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch Things gets really dramatic when you look specifically at infanticide, something crows also do, albeit it seemingly extra rarely. 10:31 am 29 May 2019 18 Retweets 221 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch For example cliff swallows may destroy their neighbor's eggs so that they can drop their own eggs off. sora.unm.edu/sites/default/. 10:31 am 29 May 2019 18 Retweets 213 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch And of course some mammals like brown bears, lions, most primates, many dolphins etc. will commit infanticide in order to mate with the female(s) 10:31 am 29 May 2019 23 Retweets 231 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch And I'll never forget, during my stint on a caspian tern colony, watching curious babies take a mere couple steps too far from their nest only to be bombarded with pecks from their angry adult neighbors, resulting in a confused panic which led them further astray & usually dead 10:31 am 29 May 2019 21 Retweets 236 Likes
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    Text - Kaeli Swift, PhD Follow @corvidresearch In conclusion: yes crows sometimes kill each other for reasons that are complex and not always clear, especially at this time of year, and not unlike many other animals. GIF 10:31 am 29 May 2019 24 Retweets 431 Likes

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