Birds of a feather splat together

...behavioural differences suggest that individual birds that are not killed in traffic should have larger brains for their body size. We analysed the link between being killed by traffic and relative brain mass in 3521 birds belonging to 251 species brought to a taxidermist. Birds that were killed in traffic indeed had relatively smaller brains, while there was no similar difference for liver mass, heart mass or lung mass. These findings suggest that birds learn the behaviour of car drivers, and that they use their brains to adjust behaviour in an attempt to avoid mortality caused by rapidly and predictably moving objects. 

Which is presumably why the panicky, feather-brained pheasant seems to be in almost as much danger of ending up as roadkill as it is of being blasted out of the sky by some feather-brained toff with a shotgun. The altogether smarter crow, on the other hand, will view your approaching vehicle with bored contempt, then grudgingly hop out of the way at the very last, precisely-timed, moment before returning to resume its rudely-interrupted meal of carrion (pheasant, if it's lucky).