...also if anag 'the road' could somehow be combined with a 't' from another word in the clue then that gives 'throated' - a component of many, many bird names. [and believe me, I've looked at lists and lists!]
From bobbinwales's idea, and his idiosyncratic English usage, can I suggest that it's an anagram of 'they are' shortened (erroneously) to 'there', 'road' and 'slows' (for traffic loses speed) to give 'short-eared owls'. ;-)
Ha, yes indeed I have mangled the English language in many posts on here!
But I now think theres a simpler explanation of short eared owls which dosn't rely on mangling they're into there.
Perhaps on = about or RE. So anagram of RE THE ROAD and SLOWS.
There might be another explanation involving the even letters of rOaD or even letters of bEfOrE