In English, calling someone a bird brain is the equivalent to labeling them a dumbbell. Bird brains are small and synonymous with stupidity, although avians are clever enough to make tools, have memories, and even commit crime.

Now, new research confirms bird intelligence yet again, indicating that the smarter ones among them study our behavior and use their brains to adjust to a relatively new human activity.

A study published in the Royal Society Open Science March 29, led by evolutionary biologist Anders Moller of the University of Paris-Sud, linked relative bird brain size with the ability to survive. Birds with bigger brains are less likely to be killed in traffic, he found, as they can apparently better perceive oncoming traffic and avoid smashing into cars. The study also seems to indicate that bigger brained birds can better shirk human hunters.

To arrive at this conclusion, the evolutionary biologist studied the brains and bodies of 3,521 birds killed in Denmark. The creatures were from 251 different species collected between 1960-2015 by taxidermist Johannes Erritzoe, who had carefully noted the cause of death for each when he received them or conducted an autopsy. Their review of these bird brains, as compared to other organs in the body, showed a link between survival and brain size.

Moller writes, “Birds killed by cars have disproportionately small brains for their body size. In contrast, there was no difference in terms of the size of the liver, heart or lungs. Both road kills and birds being shot had disproportionately small brains for their body size.” He believes that the findings suggest that cognitive differences between dead birds and survivors may be linked to differences in perception and adjustment to movement.

In other words, big brained birds seem to be smarter at dodging oncoming cars, indicating that they are more intelligent. This may be a sign that over time, where there is a lot of traffic, birds face evolutionary pressure to get smart or die.