Tweets, emails, instagram posts, whatever. Obviously not openly talking about illegal activity, but Diana is simply looking for an increase in activity after reports of syndicate member deaths have gone out. Who starts sending messages to others asking if anyone knows what happened, who did it, was anything found, etc., using words or phrases that might seem like code, and does activity by the syndicate change in areas where they’re believed to have a presence. Things like that. She’s watching for the ripple affect online.
That foliage isn’t thick enough to camouflage completely, and satellites do have other visions in their lenses, hence why Diana is able to follow along when 47 kills a target and he’s not even near them: infrared satellite.