You answer the call and nobody says a word, yeah, that will certainly result in a donation, slimeballs.
These calls are from "The Share Group".
Their website states
"Our core business is comprised of outbound telemarketing services: fundraising, membership mobilization and affinity sales calls. We are however a full-service provider, with offerings that include inbound calling programs, activist recruitment, online giving options, e-mail address collection and e-mail pledge fulfillment."
If you call the number back, you get a recorded message stating something like:
The number you have called belongs to "The Share Group", a call center for non-profit organizations which you may have donated to in the past.... you can select Option 2 to have your number taken off the call list... but it may take up 72 hours for your request to be processed...