May 15, 2017 by Loretta Waldman
New research shows climate change is altering the delicate seasonal clock that North American migratory songbirds rely on to successfully mate and raise healthy offspring, setting in motion a domino effect that could threaten the survival of many familiar backyard bird species.
A growing shift in the onset of spring has left nine of 48 species of songbirds studied unable to reach their northern breeding grounds at the calendar marks critical for producing the next generation of fledglings, according to a paper published today in Nature Scientific Reports.
That's because in many regions, warming temperatures are triggering plants to begin their growth earlier or later than normal, skewing biological cycles that have long been in sync.
"The birds are trying to keep us with the speed of climate change but they can't…it's just too fast," said Morgan Tingley, assistant professor of ecology and evolutionary biology at the University of Connecticut, and a study author. "They can't adapt quickly enough."
The multi-institutional study used data from satellites and citizen scientists to study how quickly the interval between spring plant growth and the arrival of 48 songbird species across North America changed from 2001 to 2012.
Researchers found the gap lengthened by over half a day per year across all species on average, a rate of five days per decade—but for some species, the mismatch is growing at double or triple that rate.
Nine species were clearly unable to keep up with the shift: great crested flycatchers, indigo buntings, scarlet tanagers, rose-breasted grosbeaks, eastern wood pewees, yellow-billed cuckoos, northern parulas, blue-winged warblers and Townsend's warblers.
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