Fergus likes
Bright, indirect light
Fergus likes moderate light. Try a few metres from a window without direct light.
Humidity
In spring and summer, bird's nest ferns like moist (not wet) soil. He'll thrive in the humidity of a bright bathroom, or else will appreciate a regular misting.
Warmth
He doesn't enjoy the cold, so give him a spot away from drafts or very chilly rooms (but not by a radiator).