Researchers from Florida State University are studying Rocky Mountain bumblebees, and researcher Doctor Jane Ogilvie says the warmer weather is stretching their limited food supply over a longer season.
It's like too little butter spread over too much bread.
Scientists say the warmer weather means bees have more time to forage, but there's no corresponding increase in flowers.
"We have about the same amount of flowers in a season consistently over four decades," Ogilvie said. "But it's getting spread thinly over the season."
The result is a decline in bumblebee populations.
Ogilvie says the link between climate change and the health of pollinators is becoming impossible to ignore.