Blue Jays Mob and Imitate Hawks

I'm guessing an experienced birder can probably tell the difference between a blue jay's imitation of a hawk call and an actual hawk call. I'm not sure I'm there yet but I have observed a blue jay imitating a hawk and have gotten pretty accurate, based on where a call is originating from, deciding if the hawk call I am hearing is real or imitation. I used to go in search of the hawk I was hearing and wonder why I could not find such a big bird in the direction of the call. One day I finally saw a blue jay making the call when I zeroed in on the sound. I knew blue jays were one of the birds that would pester, or mob hawks, but until then I did not realize they also impersonated them.

I have read a few thoughts as to why they do this, such as alerting other birds to an actual hawk danger or scaring off other birds. I have not been able to tell exactly what my blue jay impersonators are trying to accomplish. I have heard several of them go into extreme blue jay alarm call, but not a hawk imitation, when there has been a small hawk around. I found this example of a clever blue jay doing a hawk call to scare off other birds, thus reducing competition at the bird feeder.

While I have seen a half a dozen or more blue jays sounding the alarm and mobbing a hawk perched in a tree in my pasture, I have also noted a single blue jay making an alarm call and mobbing a hawk as seen in my photographic art images of this post (click to enlarge). The hawk seems mighty calm or even unimpressed at the antics of the blue jay. These images were taken in early May so it is possible that the red-shouldered hawk perched on the light pole was too close to the blue jay's nest for comfort. Or perhaps some blue jays just enjoy picking on the raptors and getting away with it.