Is it a new silent spring?

Global warming may be turning some songbirds away from insects that are a mainstay of their diet, a new study shows.

Black-capped chickadees dine on caterpillars, but scientists found they have a strong aversion to caterpillars that consume leaves rich in two chemicals formed when plants take up too much carbon dioxide. CO2 is the gas from vehicles and industry that many scientists believe is heating the planet.

Effects have apparently rippled into the food chain: Increased chemicals in leaves deter insects too, which could mean fewer bugs for birds and other critters.

The study, conducted by researchers from the University of Rhode Island and the University of Wisconsin, is the latest to link climate change to disruption of ecosystems, species extinction or migrations of flora and fauna.

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-- Gary Polakovic