2007 XK cabriolet 93,000 miles. Slight "chirping" emanating from right side air vent. Goes away when climate control is shut off. Returns when system on either in auto or manual. Read hat could be leaf or other debris in vents or bad blower motor. Any other thoughts?

 

Most likely a piece of tape. I doubt debris can enter the system with a filter installed. Use an inspection camera.

You could listen carefully to the motor itself, by turning the fan speed, if its the motor it will change with speed.

 

https://www.jaguarforums.com/forum/xk-xkr-x150-33/x150-replacement-blower-motor-156145/

 

The chirping sound emanates from the blower motor on the passengers side. It probably got wet, due to the typical failure of the condensation of water in the airco.
I had the same problem, it disappeared after I changed the blower motor. Mind you, check first if there are signs of water on the passengers side. If you don't correct the blockage of the duckbill, your new motor is due to fail as well in time.