Despite birds being heavily studied members of forest communities, few generalities exist regarding species response to fire. Further, there very few studies of bird communities outside the breeding season. Quality of nonbreeding habitat is critically important to migrants, local transients, and wintering species, and changes to nonbreeding habitats can have important consequences for communities across seasons. In 2015, the Rough Fire burned part of the Grant Grove sequoia forest within Sequoia Kings Canyon National Park (SEKI) in areas with different fire management histories. Subsequently, SEKI deployed acoustic recording units (ARUs) at nine stations in five sites in areas with (prescribed and wildfire) and without prior fire management activities (old growth and second generation mature forest). The aim of this study was to test the effects of these fire histories on nonbreeding community composition by quantifying and comparing species richness and composition in fall and in winter. A secondary aim was to determine the efficacy of manually detecting winter species from surveys of nonbreeding-season recordings. Random 10-minute samples were manually surveyed from each point recording six times September 2017 – Februrary 2018 for a total of 540 minutes surveyed. Differences in richness and composition between fall and winter were analyzed by site type and sites organized into fire history categories. Richness was evaluated with a general linear mixed model and a Poisson regression with fixed factor effects to test for significance. Differences in species composition were compared and tested with non-metric multidimensional scaling (NMDS) using a community-by-species matrix. Frequency was examined to evaluate individual species contribution to composition. There were 45 total species detected, 22 across both seasons. Winter season had significantly lower species richness (ß = -0.88, p < 2e-16) than fall. The second generation mature forest (ß = -0.4, p = 0.033) and the site burned during the Rough Fire (ß = -0.3, p = 0.09) both had significantly lower species richness in winter. The prescribed fire history category had significantly greater species richness (ß = 0.37, p = 0.002). Species richness was also significantly higher at sites with increasing numbers of prescribed fires (ß = 0.12, p=0.0023). Species composition was more similar in fall than in winter. There were significant differences in species composition among all sites (r2=0.80, P=0.02) and for three of the five fire-associated categories in winter: sites with and without fire history (r2=0.4, P=0.01), with different time since fire (r2=0.52, P=0.01), and increasing total number of prescribed fires (r2=0.86, P=0.01). Differences among sites grouped by prescribed fire or wildfire did not significantly correlate with species composition. Overall, this study indicates that fire history positively affects winter bird communities, and demonstrates that acoustic recordings are effective in detecting winter species. This baseline investigation will benefit SEKI’s efforts to understand how to best use these long-duration recordings for examining relationships between species and habitat, and future studies of how fire histories affect winter communities. Understanding the differences in these avian communities can assist land managers in protecting associated birds in fire-prone landscapes across all seasons.

In this dissertation, I explore the reproductive biology of seabirds, from ecology and evolution in chapter one to physiology and behavior in chapter two, then take a conservation methods approach in chapter three. In chapter one, I investigated how flexibility in diet affects interannual variability in seabird breeding phenology, the implications for interannual variability in reproductive success, and then evaluate the findings in the context of human-induced rapid environmental change. To this end, I compiled three large datasets of seabird phenology, diet, and productivity spanning from 1970 to the present and analyzed them using a combination of structural equation models, mixed-effect models, and meta regression. I found that generalists exhibited greater interannual variability in reproductive phenology than specialists but also had more consistent (but middling) reproductive success. Seabird reproductive phenology is growing later globally, and generalists exhibited greater magnitude of change than specialists. Worryingly, seabird reproductive success has declined by 6% in the past 50 years, with no difference between generalists and specialists. This contradicts evidence from other systems that diet generalization will provide some resilience against human-induced environmental change. In chapter two, I took a more proximate perspective and explored the benefits of perennial monogamy to individuals in Cassin’s auklet Ptychoramphus aleuticus. Improvement in reproductive outcomes with pair experience (termed the mate familiarity effect) has been observed in many species of perennially monogamous animals, but the mechanisms by which benefits are conferred have proved difficult to identify. To investigate mechanisms of the mate familiarity effect, I collected nest attendance data, body condition information, levels of the hormones prolactin and corticosterone, and followed individual nests to fledging to measure reproductive success over two years with very different oceanic conditions. I found evidence that the mate familiarity effect is due to physiologically mediated differences in behavior, and that the benefits seem mostly to be conferred by the male. I found that male attendance is correlated with female attendance in a pair-experience dependent manner, and that the relationship of plasma prolactin to male attendance changes depending on the attendance of the female. Females, however, appear to be using less external information and have attendance correlated primarily with internal information: levels of prolactin, corticosterone, and their own body condition. Hatching success was determined primarily by the effect of year, with almost complete nesting failure in 2019 and almost complete success in 2021. There was a trend, however, of better male attentiveness in the few eggs that hatched in 2019 compared with the eggs that failed. There was no such trend for female attentiveness. Similarly, in both years, male attentiveness was correlated with greater maximum chick weight, but there was only an effect of female attentiveness when the female entered the breeding season in good condition. Together, these results suggest that the female is energetically limited in the quality of care she can provide, and that the male is integrating information about her behavior, which is the primary determinant of post lay reproductive success. Experience with his mate may improve his ability to respond to her behavior, leading to improved hatching success and maximum chick weight. These results highlight the importance of social bonds in reproductive partnerships, as well as the different but complementary roles played by each partner. In my third chapter, I evaluated the effectiveness of using radio frequency identification (RFID) technology to improve monitoring and conservation of the imperiled Ashy storm petrel Oceanodroma homochroa. The Ashy storm petrel is a small, elusive seabird that nests in inaccessible rocky crevices. Despite approximately 50 years of conservation monitoring and study, very little is known about their reproductive biology. I equipped individuals captured in mist-nets with passive integrated transponder (PIT) tags in 2018 and 2019. In 2018, I deployed stationary RFID readers in an array in areas of known storm petrel nesting activity to identify nest sites. In 2019, I took a more active approach, using a mobile backpack RFID reader to scan likely storm petrel nesting habitat for tagged birds. Both methods yielded little usable information. I concluded that although RFID technology has great potential for monitoring elusive species, the range is insufficient to detect individuals that may have many potential entrances and exits to the nest site and that nest in rocky habitat that obstructs the signal from PIT tags.