Biodiversity 4 min

Macaws that blush: facial expressions demonstrated for the first time in birds

PRESS RELEASE - Up to now, the question of positive emotions in birds has received little attention, research having focused mainly on stress-related behaviour. In order to carry out studies of facial behavioural indicators, INRA scientists teamed up with the Beauval Zoo to look at blue-and-yellow macaws (Ara ararauna), who have the distinctive characteristic of having a portion of their cheeks devoid of feathers. During their experiment, the scientists were able to describe for the first time facial expressions in the birds within a context of positive valence: the macaws blushed and ruffled their crown feathers. These initial findings are opening up new avenues for studying how facial expressions act as visual clues that can communicate the emotional state of individual birds within their social groups.

Published on 22 August 2018

illustration Macaws that blush: facial expressions demonstrated for the first time in birds

The scientists observed the behaviour of macaws from the Beauval Zoo that are trained on a daily basis by caretakers for a bird show. The birds are therefore in close contact with humans, and a relationship of trust has been forged. To begin with, a list of observable parameters on the birds’ faces was established. The scientists identified three zones where feathers can be ruffled independently: the crown (top of the head), nape and cheeks. They also observed variations in the skin colour on the birds’ cheeks, going from white to red in seconds. Then the scientists used the human-animal relationship to observe these parameters within a context of contrasting emotional valence. The experiments consisted of observing birds during a two-part session: first the caretakers placed the birds on a perch and stood in front of them, interacting with and talking to the animals while looking at them (positive valence for birds). During the control phase, the caretakers kept the same distance from the birds but did not interact with them, turning their backs on the animals (less positive valence).

Each session was repeated ten times for all five birds used in the experiment. The entire experiment was recorded on film, and close-up photographs taken of each bird’s facial profile during and at the end of the sessions. The scientists then deciphered all of the footage and still photography. Naïve observers looked at the photographs and took note of the zone around the birds’ eyes, looking specifically at the colour, white or red. As for the films, they were paused every five seconds so that observers could take note of the position of feathers on the crown, nape and cheeks, according to the established list, i.e. sleek or ruffled.

The findings1showed that ruffled feathers on the crown was more frequent during the phase of mutual interaction between the macaws and their caretakers. Likewise, blushing on the birds’ cheeks – described for the very first time – was more frequently observed during this same interactive phase.

A: targeted zone observed by naïve observers; B: example of a photograph where all observers noted blushing; C: example of a photograph where no observers noted blushing.

The scientists also observed the birds in groups, in their living environment. They observed more frequent head feather ruffling when the birds were engaged in activities with positive valence and low-arousal levels, such as rest, positive social contact and when given some form of enrichment.

These ground-breaking findings in birds offer the first indicators of arousal level and/or emotional valence, which are key components of the emotional state of animals.

Further study is needed to understand the range of emotions encoded by these facial expressions, and what role they play in the interaction that takes place in social groups. Until now, blushing was thought to be unique to humans. But blushing observed on the cheeks of macaws could contribute to a better understanding of the evolutionary origins and function of this visual indicator.


1 Reference: Bertin A, Beraud A, Lansade L, Blache M-C, Diot A, Mulot B, et al. (2018) Facial display and blushing: Means of visual communication in blue-and-yellow macaws (Ara Ararauna)? PLoS ONE 13(8): e0201762.

Service presse INRAE


Aline BERTIN Scientific directorJoint Research Unit "Reproductive and Behavioural Physiology" (INRA - CNRS - Université François Rabelais de Tours - IFCE)

Service presse du ZooParc de Beauval



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