Researchers for the Ministry of Transport found over 200 dead crows near greater Manchester 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 colours of paints appeared on the bird's beaks and claws. By analysing 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.
MofT then hired an Ornithological Behaviourist to determine if there was a cause for the disproportionate percentages of truck kills versus car kills.
The Ornithological Behaviourist 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 "Lorry."