Crows removing ticks: helpfulness, opportunism, or something else?

Guest post by Thom van Dooren

If you’ve spent much time at all watching YouTube videos of corvids, you’ve likely come across some of the numerous examples of them engaging in the seemingly helpful act of removing ticks and other ectoparasites from all kinds of other animals. The lucky ‘client’ might be a rhino, a sambar deer, or a cow.  Admittedly, it isn’t always entirely clear that these crows are being exclusively helpful, engaging in what biologists call symbiotic cleaning. In at least some of these cases, there seems to be a reasonable chance that they’re (also) playing, pestering, or even getting ready to take a bite out of an unsuspecting animal. 

In a few cases though, the results of their cleaning work speak for themselves. One recent set ofcamera trap videoscirculating at the moment on social media shows a group of corvids, probably Torresian Crows (

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