This week's paper is in Global Change Biology and is co-authored by three former Kent Island Directors. It is lead-authored by Bob Mauck of Kenyon College, with Don Dearborn of Bates College, and (posthumously) Chuck Huntington of Bowdoin. The three directors used long-term data collected on Kent Island to study the effects of global temperature on reproductive success in Leach's storm petrels. Data on temperature has been collected on Kent Island since 1939, and the storm-petrel dataset was initiated by Chuck Huntington in 1955. In this week's paper Mauck et al. examined the effects of local (Kent Island) temperature, global mean temperature (a combination of air and sea temperatures), and sea surface temperature on reproduction of storm-petrels using 56 years (1955-2010) of the Kent Island long-term databases on weather and petrel reproduction. The best fitting model for predicting storm-petrel reproductive success included both global mean temperature and local temperature on Kent Island, but global mean temperature is the most important predictor of reproductive success in storm-petrels.
Mauck et al. found that as temperatures rose between 1955 and 1988 storm-petrel hatching success increased (likely due to decreased incubation costs), until in 1988 it appears that global temperatures reached a critical point, and since 1988 hatching success as declined as global temperatures have continued to rise. The decline in hatching success since 1988 is most likely due to the negative impacts of increasing temperatures on food availabilities for petrels as fish move further northward and into deeper waters.
The effects of increasing temperature, however, were not the same on all birds. Birds with more breeding experience have higher hatching success in general, and appeared to be somewhat buffered against these effects of climate change. The effects of increasing temperatures on hatching success were more strongly observed in less experienced petrels (both positively before 1988 and negatively afterword). Mauck et al. propose that this is because less experienced petrels are less effective foragers, and therefore have benefitted more from reduced incubation costs with increased temperatures, but suffered more from reduced food availabilities.