canary in the coal mine

plural canaries in the coal mine · plural canaries in coal mines · plural canaries in the coal mines

1. alternativeAlternative form of canary in a coal mine.

   Sex is the canary in the coal mine. It's the first thing to go when a marriage is in trouble.

   2009, Erica Manfred, He's History, You're Not: Surviving Divorce After 40, GPP Life, →ISBN, page 167

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   The second canary in the coal mine — along with the Arctic— is Antarctica, the largest mass of ice on the planet by far.

   2006, Al Gore, An Inconvenient Truth: The Planetary Emergency of Global Warming and What We Can Do About It, Rodale, →ISBN, page 176

   Many authors state, almost as a truism, that amphibians are more vulnerable to environmental insults than are other vertebrates and therefore might serve as a kind of “canary in the coal mine,” an indicator of environmental degradation (e.g., Carroll 1999).

   2007, Kentwood D. Wells, The Ecology and Behavior of Amphibians, The University of Chicago Press, →ISBN, pages 784–785