200 dead crows near greater Boston recently, and there was
concern that they may have died from Avian Flu. A bird
pathologist examined the remains of all the crows, and, to
everyone's relief, confirmed the problem was definitely not
Avian Flu. The cause of death appeared to be vehicular impacts.
However, during the detailed analysis it was noted that varying
colors of paints appeared on the bird's beaks and claws. By
analyzing these paint residues it was determined that 98% of the
crows had been killed by impact with trucks, while only 2% were
killed by an impact with a car.
MTA then hired an ornithological behaviorist to determine if
there was a cause for the disproportionate percentages of truck
kills versus car kills.
The ornithological behaviorist very quickly concluded the cause:
When crows eat road kill, they always have a look-out crow in a
nearby tree to warn of impending danger. They discovered that
while all the lookout crows could shout "Cah", not a single one
could shout "Truck."