Warning Colouration Puns

There was concern that they might have died from Avian Flu. An avian pathologist examined the remains of the crows, and to everyone's relief, confirmed the problem was definitely not avian flu. The cause of death was vehicular impacts.

However, during the detailed analysis it was noted that varying colours of paints appeared on the birds beaks and claws. By analyzing these paint residues it was determined that nearly 96% of the crows had been struck by trucks, while only 4% were car impacts.

The MTA then hired an Ornithological Behavourist to determine the reason for the disproportionate percentages of truck kills vs car kills. He very quickly concluded the cause: When crows eat roadkill, they have a look-out crow nearby to warn of impending danger. They discovered that while all the look-out crows could shout "Cah!", none could shout "Truck!"