Alight, Light, Land, Perch and Roost share the meaning to come to rest after or as if after a flight, a descent, or a fall.
Alight suggests previous controlled or gentle movement through the air or open space (as of a flying bird or a floating snowflake)
- skylarks alight on the ground
Light, sometimes the equivalent of alight, more often presupposes a falling or jumping than flying or floating, and sometimes merely a wandering or roving.
- he sprang from the roof and lighted on his feet
- we came smack down on the animal tent; when we lit the tent began to tear
—Sandburg
Land applies to a boat coming to land or an airplane grounding. Though often used interchangeably with light, it may connote arrival at a destination and sometimes driving force or power.
- the airplane landed in a swamp
- he fell headlong and landed on his face
- his blow landed in the spot he aimed at
- he has landedwhere he hoped, in an executive position
Perch and roost basically imply alighting of birds, but perch suggests settling on something elevated to which the claws may cling (as to a pole, bar, or twig) and roost, the settling for rest or sleep, especially by domestic fowls, on the perches and in the shelters prepared for them. So perch often implies elevation of position and tenuousness of grasp or hold.
- twenty or more [rooks] perched aloft, cawing and conversing comfortably
—Jefferies - a lofty perpendicular cliff . . . with a castle . . . perched on the distant top
—Lucas
Roost, when used of persons, often suggests a position like that of roosting fowls
- boys roosting on the rail of a fence