This company cllas many times a day daytime and nights including weekends. Caller ID says DONOR SERVICES. Never leaves a message. Very bothersome.

When I picked up the call it was a recorded message saying that it was "The World Wildlife Fund".

Yes it is the World Wildlife Fund, and they periodically make unsolicited daily calls that can last up to several weeks.  This happened to us several times and we finally decided to stop supporting WWF.  It's a shame that an organization dedicated to a good cause resorts to unethical fundraising tactics which alienates people.

I've been receiving calls daily (at all hours of the day) for the last 2 weeks. Do not answer.

Received several calls in the past couple of weeks from WWF, World Wildlife Fund, but didn't answer the phone.  They never left a message.  Called the number back in the evening, and a recorded message said it was after their usual business hours, so I left a message for them to remove our phone number from their calling list.  Hopefully, the calls will stop.