Why cats sometimes make baby cry sound?

My 18 year old female cat has recently started making the baby cry and I'm not sure what to make of it. She isn't crying in pain and she isn't being disturbed by another cat. She makes it when she is preparing either to lay on my bed pillow or on her quilt in the closet. Perhaps she is aware of scent that bothers or or maybe she is calling for me. When I stop what I am doing to try to determine what is bothering her, I find her staring at the pillow or at her quilt. None of the other cats ever goes either place, to the best of my knowledge and I live alone. Go figure.