This number has called several times a day for a couple of weeks. Caller ID shows only the phone number. Messages left from the number are garbled and end with "thank you." I answered the call today, and it was a hang-up.
Have some family from Chicago so answered. It was a woman who asked for me by name, representing World Wildlife Fund , saying that this was not a solicitation call but just a call to thank me for my support of the World Wildlife Fund (I contributed a small amount this past year). After brief conversation the call ended.