Negligible evidence for detrimental effects of infections among Emperor Geese () breeding on the Yukon-Kuskokwim Delta, Alaska.

Emperor Geese () are iconic waterfowl endemic to Alaska and adjacent areas of northeastern Russia that are considered to be near threatened by the International Union for Conservation. This species has been identified as harboring diverse viruses and parasites which have, at times, been associated with disease in other avian taxa. To better assess if disease represents a vulnerability for Emperor Geese breeding on the Yukon-Kuskokwim Delta, Alaska, we evaluated if haemosporidian parasites were associated with decreased mass or survival among adult female nesting birds captured during 2006-2016. Through molecular analyses, we detected genetically diverse , , and parasites in 28%, 1%, and 1% of 607 blood samples screened in triplicate, respectively. Using regression analysis, we found evidence for a small effect of infection on the mass of incubating adult female Emperor Geese. The estimated mass of infected individuals was approximately 43 g (95% CI: 20-67 g), or approximately 2%, less than uninfected birds when captured during the second half of incubation (days 11-25). We did not, however, find support for an effect of infection on survival of adult female nesting Emperor Geese using a multi-state hidden Markov framework to analyze mark-resight and recapture data. Using parasite mitochondrial DNA cytochrome sequences, we identified 23 haplotypes among infected Emperor Geese. haplotypes clustered into three phylogenetically supported clades designated as ' clade A', ' clade B', and 'other '. We did not find evidence that parasites assigned to any of these clades were associated with differential mass measures among nesting adult female Emperor Geese. Collectively, our results provide negligible evidence for parasites as causing detrimental effects to adult female Emperor Geese breeding on the Yukon-Kuskokwim Delta.