We all recognize that blue jays communicate with one another using a wide variety of calls; however, it is less widely known that these noisy birds also communicate with their cohorts using their crests. In fact, you can learn much about a blue jay’s state of mind by looking at how high a jay’s crest is held above its head.
Blue jays use their crests to demonstrate its level of calmness and aggression. For example, the next time you see one or more blue jays placidly feeding in your yard, undoubtedly, their crests will be held close to their heads. However, if a family cat comes into their view; their crests will instantaneously become erect. On the other hand, should the cat turn around and walk in the other direction realizing the feline no longer poses a threat; the birds’ crests will drop. Similarly, if a blue jay is startled by the arrival of a bird the blue jay perceives as a competitor for the food it is dining on, such as an American crow, the jay will erect its crest. By the same, if a cardinal alights near a feeding jay, the blue jay might not raise its crest at all.
How high a jay erects its crest is indicative of its perceived level of threat or agitation. For example, if a blue jay notices a hawk circling in the sky some distance away, it may not fully raise its crest. However, once the hawk flies close enough to where the jay senses it poses an imminent threat, its crest will then become fully erect.