Yes ... it is!
I was about to report no sightings or sounds of noises coming from my A/C vent (since my original post), but then I heard it!!!
It sounds like a bird. I think I heard some wing flapping going on down there. I didn't close the vent this time, just covered it with a toy. Same vent, by the way. Oh crud! It's going crazy in there! I'm going crazy out here!! It's trying to get out! I can hear it thumping and flapping and scratching!
I didn't feel well this morning, so I didn't go to church. Joe took all the children, and because I am a big scaredy cat I'm dying here alone!
Joe didn't get home from work on Friday until after 8 pm. Then he had to work yesterday and didn't get home until after 7 pm. He hasn't had time to investigate, but in all fairness, I have not heard anything since Friday.
I think I'm getting crampy now ...