Western Grebes (Aechmophorus occidentalis) winter on the West coast of North America and travel inland to breed in fresh water lakes and reservoirs. Preening is a maintenance behavior in which individuals adjust and maintain their feathers. This is a particularly important behavior for water birds because it helps maintain certain water-proofing properties of the feathers necessary for heat retention. Preening is only one important behavior that a grebe must engage in throughout the day. They must also forage, be alert for potential predators, and court potential mates so the grebes must prioritize their time and energy effectively. The purpose of this project was to examine how preening behavior varies with time of day. We conducted the project at Lake Cascade in Cascade Idaho for five weeks between June and July of 2017. We observed Grebes during three set observation periods: morning (0600 – 0900); afternoon (1200 – 1500); evening (1800 – 2100). During each observation period we would observe 10 individual grebes for 5 minutes each. We recorded the total number of preening actions performed by each grebe during this time.
Results/Conclusions
We observed a total of 308 individual grebes throughout the study period. We found that the amount of preens performed varies significantly (p < 0.5) between times of day and is highest during the evening. These results suggest that grebes are most active in the morning and evening with the evening being particularly important for maintenance behaviors such as preening. The waters that western Grebe inhabit in Idaho are popular recreational areas with high boating usage. If grebes are disturbed during key preening time there may be fitness consequences due to the decreased maintenance. Understanding when grebes are most likely to engage in maintenance behaviors may be able to inform recreational regulations and conservation plans in areas where Western Grebes are present.