Yes, MIGRATIONS is a Scrabble word!

Letter values in Scrabble US: M 3, I 1, G 2, R 1, A 1, T 1, I 1, O 1, N 1, S 1.

Is it a valid word?

MIGRATIONS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the movement of persons from one country or locality to another
a group of people migrating together (especially in some given time period)
(chemistry) the nonrandom movement of an atom or radical from one place to another within a molecule
the periodic passage of groups of animals (especially birds or fishes) from one region to another for feeding or breeding