It merely required a government agency to to get involved.
Researchers for the Highways Agency recently found over 200 dead crows near Gatwick Airport on the M23 recently, and there was concern that they may have died from Avian Flu or some other imported pathogen.
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 lorries, while only 2% were killed by an impact with a car.
The Highways Agency 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.
The conclusion was that while all the lookout crows could say “Cah”, none could say “Lorry”