Blue Jay Alarm Calls and Imitating a Sharp-shinned Hawk

In the video, a female Blue jay I have known for 5 years, makes a few different alarm calls. The first one is a call I have only heard her make. I know about 20 blue jays and haven't witnessed the others making it, that isn't to say that they don't though. When she makes this call it can be for either hawks or crows.
The second call is of her imitating a Sharp-shinned hawk. They use this imitating of hawks to alert other jays and also sometimes to decieve others into thinking a hawk is around. In this case she was alerting her mate of a Sharp-shinned hawk that was near. The last call is just a regular jay alarm, again letting her mate know of the hawk.