When I was in school, some professors noticed that the crows on campus were astoundingly intelligent. These crows recognized that when lights were green, cars could go and when they were red, cars would stop. Using this knowledge, the crows would put nuts on the crosswalk so that during a green light, they'd be run over by cars and their shells cracked for the crows, to be collected at a red light. Or so it seemed.
Unfortunately, despite showing signs of understanding the signals, a lot of crows were dying, being bludgeoned to death. Upon examination, they discovered that the crows were specifically only being hit by large vehicles. This fascinated our professors.
As a result, the professors setup cameras to monitor the actions of the crows.
What they discovered was that the crows actually had a lookout crow who was signalling to the other crows when cars were coming and when they were not.
After a lot of monitoring and research, the professors discovered that it was a lack of adequate crow-to-crow communication that was causing the crows to be killed by larger vehicles.
As it turned out, the crows could only say "Caw! Caw!" and couldn't say "Truck! Truck!"