The Effects of Owl Decoys and Non-threatening Objects on Bird Feeding Behavior

As traditional agricultural practices change, the scarecrow has also been renovated and modernized to include mock natural predators, such as owls, hawks, and falcons instead of comical human representations. These facsimiles represent an excellent opportunity to examine anti-predatory tactics and vigilance behavior in birds as a response to perceived threats. In this study, we tested songbird reaction to an owl decoy that mimicked the presence of a predator and to a non-threatening object placed in an oak woodland within Oregon’s Willamette Valley. Frequency of bird visitations to bird feeders when either a plastic owl or a cardboard box of similar size was used to examine the effect of the presence of a predator on bird feeding behavior. We hypothesized that introduction of a model owl would reduce the number of birds observed at a nearby feeder, but a cardboard box would not have a significant effect on bird presence. Using paired t-tests, we determined that a false predator was effective in deterring bird species from feeding, while a box was not

Roost selection and social organization of myotis in maternity colonies

Wild animals often congregate in social groups to enhance individual and group survival. Social cooperation allows animals to share limited resources among conspecifics without incurring the costs of competition. Many reproductive bats demonstrate social cooperation by congregating in maternity colony roosts, which are critical but limited habitat components for North American bat populations. Female myotis bat species may select artificial structures, such as bat boxes and buildings to form their colonies, and may move among multiple roosts throughout the season. Female little brown bats (Myotis lucifugus) and Yuma bats (M. yumanesis), for example, form maternity colonies during the summer to rear their young. I studied two colonies in artificial structures near Vancouver, British Columbia, to assess social behavior and understand what conditions influenced day roost selection. During summer 2019, I used Passive Integrated Technology (PIT-tags and scanners) to track individuals’ daily roost selection. I monitored temperature and humidity at all known roosts and used radio telemetry to find previously unknown roosts. Yuma myotis and little brown myotis used at least 5 roosts at each site and switched locations frequently between roosts. Bats selected roosts within specific temperature ranges likely corresponding to their thermoneutral zone. Bats were less likely to switch during lactation when the pups were vulnerable and most likely to leave a roost during post-lactation when the pups were volant. Yuma myotis and little brown myotis formed strong, close associations with conspecifics during pregnancy and lactation, which then fragmented during post lactation when adults could roost independently with volant pups. Little brown myotis left the maternity site in August, while Yuma myotis persisted until September. During this time, Yuma myotis mixed with conspecifics from nearby maternity colonies in a previously unoccupied roost. My findings suggest land managers should ensure that multiple nearby roosts are available to maternity colonies, as bats in a maternity colony require a range of temperatures and roost types during the summer. Yuma myotis and little brown myotis may have similar roost requirements, but different social behavior, suggesting that these two species have different life history patterns.Science, Irving K. Barber Faculty of (Okanagan)Biology, Department of (Okanagan)Graduat