The abundance and relative composition of helminth communities in the lower gut of LESC differed among regions. Total helminths and % trematodes increased and % cestodes decreased with increasing latitude. Measures of scaup health differed by region, and generally decreased with increasing latitude. Perturbations in health parameters that can be associated with infectious disease or other health insult (e.g., PCV, increased lymphocytes, reduced heterophil/lymphocyte ratios, reduced monocytes) reflected the geographic pattern of infection with the highly pathogenic trematode Sphaeridiotrema pseudoglobulus. However, some exceptions were apparent and may reflect the combined effects of healthy and infected birds. For example, CMRV included LESC from Mississippi River pool 19, considered high quality habitat, and pool 12, where ducks were infected with S. pseudoglobulus. Patterns of variation in measures of condition were less clear. For example, fresh mass of LESC increased with latitude, with the exception of ducks from UMRV in 2014. This was reflected in lower carcass lipids, triglycerides and NEFA and increased BHB in that sample. Ducks collected from IRV were in poorer condition in 2015 than 2014, judging by a decline in carcass lipids without a concomitant decrease in mass. These results suggest interactions between annual wetland conditions (i.e., food availability) and infectious disease agents (highly-pathogenic intestinal helminths). In the sequel, we intend to further explore these patterns and interrelationships with the addition of the outstanding 2015 LESC health data, helminth community analyses, and incorporation of wetland quality indices.
|Name||INHS Technical Report 2015 (24)|