There are only two places to charm a Raven, both in in Sacnoth Valley (see map):
On an inaccessible hilltop near Dalada Uplands. Although you can't reach it, you can still get in range to charm it when it is close to the edge of the hill.
Near the center of the southern edge of the zone. The nearby enemies will not attack the raven, making it easy to clear the area before charming it. If the raven does die, rezone at Rragar's Menagerie and try again.
The Raven is one of four pets that appear to fly when they move.