Can researchers conceal their scent from predators in artificial nest studies?

Artificial nests have been used extensively to study nesting ecology of several avian species. However, the effect of human scent on depredation rates of artificial nests has been questioned. Researchers leave scent trails as they move through brush conducting field experiments, and the trails may be used by predators as cues to locate nests. Researchers have attempted to limit the effect their scent may have on depredation rates of nests, but methodologies have not been tested. We used depredation rates of artificial nests to test our hypothesis that humans cannot conceal their scent from predators. We equally divided 300 artificial ground nests among 15400-m transects. Each treatment (human scent masked by a neutralizing agent, human scent masked by dog scent, and human scent as a control) was replicated evenly among the transects. We checked nests every 3 days over a 24-day period and recorded depredated nests. We detected no differences in rates of depredation between the 3 treatments. Predators that use olfaction as their primary means to locate prey were capable of locating nests despite our attempts to conceal our scent trails. Although researchers often include scent-masking methodologies within depredation studies of artificial nests, such attempts appear ineffective.