The earlier, longer, less-intense peak may be disrupting animals' yearly patterns as well. For example, hummingbirds time their nesting so that their eggs will hatch during the spring peak's bounty of nectar. Now, the hummingbird hatchlings may be out of sync with the peak or supply of nectar may be smaller.
Riddle of Early Bird Migration Cracked
The first spring blossom burst six days earlier per decade in the long-term study. Approximately half of the alpine flowers now open their first blossoms earlier. The last flowers of the fall bloomed three days later per decade.
Beyond timing, the wildflowers have altered their life cycles in complicated ways. Also, flowers that used to bloom at the same time may now be out of sync. Others may now flower in unison that didn't before.
These changes may be rippling out to affect the lives of other animals, like the hummingbirds, and plants in Colorado's alpine meadows.
IMAGE: Yellow wildflower. In the background Mount Mestas (3,528 metres), Rough Mountain on the right. (Wing-Chi Poon, Wikimedia Commons)