Yes, REDSTARTS is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, D 2, S 1, T 1, A 1, R 1, T 1, S 1.

Is it a valid word?

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

flycatching warbler of eastern North America the male having bright orange on sides and wings and tail
European songbird with a reddish breast and tail; related to Old World robins

Also: american redstart, setophaga ruticilla.