english: When methane built up, or carbon dioxide built up, or oxygen was diminished, the birds would swoon before people would -- so it acted as an early warning system: Hey, get out of the mine. Things aren't going so well.
non_english: Kada bi nivo metana ili  ugljen-dioksida porastao, ili kada bi nivo kiseonika opao,  ptice bi izgubile svest pre ljudi, tako da je to služilo kao sistem upozoravanja: Hej, izlazite iz rudnika. Stvari baš i ne stoje najbolje.