Does Weather or Site Characteristics Influence the Ability of Scavengers to Locate Food?
Olfactory predators and scavengers rely on odors to locate food, and they forage primarily at night. We hypothesized that weather (e.g. wind speed, humidity, and temperature), vegetation, and landscape features affect the dissipation of odors in the atmosphere and, thus, impact the foraging efficiency of olfactory predators. We tested this hypothesis by assessing what conditions were correlated with the persistence of bait along the dike surrounding Willard Bay Reservoir, Utah. We distributed 124 chicken eggs and 199 dead European starlings (Sturnus vulgaris) as bait over 21 separate occasions spanning from May 21, 2009, to August 18, 2009. We used timers to record the time of consumption and cameras to identify which species ate the bait. Sixty-six eggs and 87 dead European starlings were consumed. The bait was consumed mostly at night (83%) and by striped skunks (Mephitis mephitis), raccoons (Procyon lotor), and red foxes (Vulpes vulpes). We used nest survival models in program MARK to determine which covariates influenced bait persistence. We tested nine variables and found that bait persistence was influenced by section of the dike, time since study initiation, temperature, humidity, and wind speed but not bait type (egg or dead European starling), terrain, or visual cover. How quickly scavengers were able to locate food, which was inversely related to rates of bait persistence, decreased with higher temperatures and wind speeds and increased with higher humidity. Our results support the hypothesis that weather and micro-habitat characteristics impact the ability of olfactory predators and scavengers to locate food.
Ruzicka, R. L. and M. R. Conover. 2012. Does weather or site characteristics influence the ability of scavengers to locate food? Ethology 118: 187-196.