Welcome to the American Ornithological Society 2018 Annual Conference. We are pleased to have you join us at the lovely Hilton El Conquistador Resort in Tucson, AZ.
Many studies have now linked changes in climate to alterations in phenology, distribution, and demographic performance of birds across taxa and geographic regions. While the past decade has witnessed an increased focus on effects of climate change on raptors throughout the world, relatively few studies have focused on raptors compared to other taxa in North America, and how changes in climate have affected their demographic performance. I examined the long-term patterns in breeding phenology and reproductive performance of Flammulated Owls (Psiloscops flammeolus) in central Colorado from 1981-2017, in an attempt to elucidate the relationship between breeding parameters and climatic factors. Data from 205 nests revealed that Julian dates of incubation onset, which decreased by 0.15 d/yr, were negatively correlated with mean temperature for the month of May, a time period coinciding with the onset of territory defense, courtship, and incubation in the owls. Number of fledglings/brood also was negatively correlated with onset of incubation, and with January-to-June precipitation, which declined by nearly half over the study period. The mean number of fledglings/brood declined by more than 35\% in years when January-to-June precipitation fell below 10 cm (2.1 + 0.1 fledglings/brood vs 1.3 + 0.3 fledglings/brood), and this decline in productivity was associated with increased nest predation by Red Squirrels (Tamiasciurus hudsonicus). No changes in density of breeding pairs were detected. Further study is needed to reveal how changes in climate may affect demographic parameters of raptors and mediate interactions across trophic levels in ecosystems.
