Investigators:
Andrew Stetter, M.S. Student

Project Supervisor:
Dr. David Haukos

Funding:
U.S. Fish and Wildlife Service
U.S. Geological Survey
Kansas State University

Cooperators:
Red Rocks Lake NWR
Jeff Warren, USFWS
Jane Austin, USGS fe

Location: Red Rocks Lake NWR

Completion: August 2014

Status: On-going

Lesser Scaup

Objectives:
Provide baseline information on scaup health and parasitemia.
Relate parasitemia prevalence and indices of health to body condition and breeding status.

Progress and Results:
The role of disease, and perhaps parasites in particular, have been largely overlooked as drivers of avian life history evolution and population dynamics with few exceptions (e.g., botulism, cholera, HPAI). Haemoproteus parasitemia is common in North American waterfowl, with prevalence of this blood parasite positively correlated with mortality rates in waterfowl. Haemoproteus parasitemia, per se, does not lead to mortality, but instead reduces an individual’s health, which may ultimately lead to lower fitness. We are conducting a study to explore relationships among parasitemia, health, and reproduction in lesser scaup (Aythya affinis). Objectives of the current study are to 1) provide baseline information on scaup health and parasitemia, and 2) relate parasitemia prevalence and indices of health to body condition and breeding status. The study was conducted on Lower Red Rock Lake, a high elevation montane wetland complex in southwest Montana. Adult lesser scaup are captured during the breeding season via spotlighting. Morphological measurements and a blood sample are taken from each individual. A size-adjusted relative body condition was calculated for each individual (BCIndex). Reproductive status of each female was determined by palpating the oviduct for the presence of an egg. The health of each individual was estimated using the heterophile:lymphocyte ratio (H-LRatio). Of the fifty birds captured, 10% were found to have blood parasites, all of which were male. Relationships between scaup relative body condition and H-LRatio were inconsistent between sexes. A strong negative relationship between H-LRatio and BCIndex for male scaup was found, indicating individuals in poor body condition were also in poor health. We did not find a similar relationship for female scaup. Breeding status of females was not related to health. There was also no relationship between presence of blood parasites in males and health.