Did you know that gas leaks were detected by birds?

In some parts of the United States, there is a curious fact that gas leaks can be detected by ravens.  So, for this purpose the gas transported through the pipeline is added to the chemical that contains rotten meat a chemical substance with the smell of rotten meat. In the event of a gas leak, the smell of that meat spreads around. A gas leak is defined as the ravens fly around this scent.