Magpie grooming elk with tick-damaged fur.

This video shows an example of mutualism between elk and magpies. I have only ever observed this behaviour in mid-February to mid/late March, so presumably the magpies are consuming winter ticks (Dermacentor albipictus) that engorge on mammal hosts at this time. Elk are habitual groomers and so don't suffer the tick damage that moose do, but the thick hair on the back of an elk's neck is difficult/impossible for them to groom as they do the rest of their body. Thus, the benefits of letting a bird land and eat the ticks out of the elk's neck fur are clear, as are the benefits to the magpie: free food!

Видео Magpie grooming elk with tick-damaged fur. канала Rob Found