Numerous organisms exhibit carry-over effects, in which previous environmental conditions impact current performance. For example, reproductive output for many migratory birds can be impacted by events during the preceding migration. Lesser Scaup (Aythya affinis (Eyton, 1838)-hereafter scaup) declined dramatically during 1970s–2000s, and there is evidence linking reduced reproductive output to reduced body condition during spring migration. In addition to food availability and quality, haemosporidian parasites (Plasmodium spp., Haemoproteus spp.) may be associated with condition of spring-migrating birds. We examined whether haemosporidian parasite infection status was linked to measures of size (mass, wing, tarsus and keel length) and condition (body fat, size-corrected mass, wing-load) in female spring-migrating scaup. Infection prevalence varied by year (21.7% in 2014; 47.1% in 2015), and percent body fat was negatively associated with the probability of infection. Body fat levels declined from ...
Merrill, L., Levengood, J., England, J. C., Osborn, J., & Hagy, H. M. (2018). Blood parasite infection linked to condition of spring-migrating Lesser Scaup (Aythya affinis). Canadian Journal of Zoology, 96(10), 1145-1152. https://doi.org/10.1139/cjz-2017-0307