California birds nesting a week earlier than they did a century agoLeave a Comment
- Earlier breeding allows birds to raise young at cooler temperatures, avoiding warming climes
November 13, 2017 University of California – Berkeley read full ScienceDaily article here
- Many birds are adjusting their life styles to breed 5-12 days earlier to avoid warming that has occurred since the early 1900s, an ongoing survey of California birds and comparison with century-old [Grinnell Survey] data shows. This strategy, combined with the trend of other birds to move northward in range or upward in elevation, allows adaptation to climate change, though eventually the cool window for breeding may become too short for some species…
- …Early spring arrivals have long been noted by the public and reported by scientists, but the assumption has been that the birds are tracking resources, primarily food: with warming temperatures, plants produce leaves and seeds earlier, and insects emerge earlier.The new study spotlights another major reason: By nesting a week earlier, birds produce eggs and young at a temperature about 1 degree Celsius (1.8 degrees Fahrenheit) lower than if they nested at the normal time in the same place. This exactly counterbalances the approximately 1 degree Celsius increase in global temperatures over the past century.
“By nesting a week or 10 days earlier, birds are avoiding some of the negative effects of climate warming,” Beissinger said…..”…we don’t know yet whether staying in place and shifting schedules earlier is a permanent solution, or only provides temporary relief from the 2 degree Celsius (3.5 degree Fahrenheit) rise in temperatures forecast to occur..”
Jacob B. Socolar, Peter N. Epanchin, Steven R. Beissinger, Morgan W. Tingley. Phenological shifts conserve thermal niches in North American birds and reshape expectations for climate-driven range shifts. Proceedings of the National Academy of Sciences, 2017; 201705897 DOI: 10.1073/pnas.1705897114