Eurasian Roller: The Smell of Fear
Rollers are one of my favorite birds, not only for its colorful plumage, but also for the splendid symmetry in the arrangement of their feathers, which is seen when their wings are extended.
This is Coracias garrulus (Coraciiformes - Coraciidae), better known as Eurasian Roller, a Near Threatened species found in Europa, Asia and Africa.
Many animals react to danger by producing chemical cues that can be smelled by others, which is called the smell of fear. Some bird species produce chemical compounds when threatened, such as nestlings of Coracias garrulus that vomit an odorous orange liquid when scared in their nests.
Indeed, a study showed that the supposedly defensive liquid which nestling rollers vomit when disturbed is smelled by parents so that they can adjust their behavior to avoid predation. Therefore, the expelling of vomit may act as a cue informing parents of a recent danger at their nests. Interestingly too, this research add to the growing body of evidence showing that birds are not anosmic (unable to perceive odors) and that they may rely on olfaction for important tasks.
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Photo credit: ©Hendri Venter
Locality: Kruger National Park, South Africa