Foraging and Calling Behavior of Carolina chickadees (Poecile carolinensis) in Response to the Head Orientation of Potential Predators

Do domestic budgerigars perceive predation risk?

Predation risk may affect the foraging behavior of birds. However, there has been little research on the ability of domestic birds to perceive predation risk and thus adjust their feeding behavior. In this study, we tested whether domestic budgerigars (Melopsittacus undulatus) perceived predation risk after the presentation of specimens and sounds of sparrowhawks (Accipiter nisus), domestic cats (Felis catus), and humans, and whether this in turn influenced their feeding behavior. When exposed to visual or acoustic stimuli, budgerigars showed significantly longer latency to feed under sparrowhawk, domestic cat, and human treatments than with controls. Budgerigars responded more strongly to acoustic stimuli than visual stimuli, and they showed the longest latency to feed and the least number of feeding times in response to sparrowhawk calls. Moreover, budgerigars showed shorter latency to feed and greater numbers of feeding times in response to human voices than to sparrowhawk or domestic cat calls. Our results suggest that domestic budgerigars may identify predation risk through visual or acoustic signals and adjust their feeding behavior accordingly.

Influences of roaming domestic cats on wildlife activity in patchy urban environments

Roaming domestic cats (Felis catus) are recognised as a threat to wildlife globally. Yet management of pet cats in urbanised areas is not regularly mandated, and management of feral cats in urbanised areas is rarely implemented. Mounting evidence emphasises the value of urban environments as hot spots of wildlife activity, which as the human population continues to grow may become the best or only habitats available to some wildlife species. Wildlife in urban environments must navigate introduced stressors that can compound with natural stressors. Additional, often novel, predators such as free-roaming pet and feral cats that are prevalent in urban environments could have high nonconsumptive fear/stress impacts on urban wildlife that influence their activity and adversely affect their health and reproduction capabilities, possibly more so than direct predation effects do. Cat roaming activity, particularly that of pet cats, could be managed with the support of the community, though motivation needs to be ensured. Understanding if roaming cat activity influences urban wildlife activity via perceived fear/stress impacts will help to build community motivation for the need for domestic cat management in urbanised areas. Using infrared motion sensor cameras positioned in both yards and green space edge habitats, we observed whether the presence and times active of native and introduced small mammals, and native birds, were impacted by domestic cat activity within a 24-h period and by their activity in the prior-24-h period. We found evidence of cat roaming activity during the hours of most wildlife activity, and show that wildlife navigated “landscapes of fear” relative to cat activity, as wildlife observed across a 24-h period increased their activity in the absence of cats in the same 24-h period and in the previous 24-h period. We also tested if cat activity was relative to previous cat activity, or disturbances, and found that cats reduced activity in response to each, but were still consistently present. Our results provide justification for the need to increase management of domestic cats in urbanised areas and offer fear/stress impacts as a novel approach to engender community support of such management.

A songbird strategically modifies its blinking behavior when viewing human faces

Even though blinking is necessary to maintain clear vision in many species, blinking is likely costly because it temporarily impairs vision. Given this cost, individuals can strategically modify their blinking behavior to minimize information loss. We tested whether a songbird species modifies its blinking behavior when viewing potential threats (human faces). We recorded the blinking behavior of captive great-tailed grackles (Quiscalus mexicanus) before, during, and after they viewed human face stimuli or control stimuli (tree bark as well as scrambled versions of human faces and tree bark). We found that the birds inhibited their blinking behavior the most when viewing human faces versus controls. In addition, they inhibited their blinking behavior more when viewing human faces that were directed rather than averted. Furthermore, when viewing the human faces, their blinking behavior was modified based on reactivity. These results suggest that a songbird can strategically modify its blinking behavior based on its perceived level of risk.

Do Carolina chickadees (Poecile carolinensis) and tufted titmice (Baeolophus bicolor) use predator eyes in risk assessment?

Previous studies have found that Carolina chickadees and tufted titmice use a predator's head orientation to determine risk, taking fewer seeds from a feeder if an avian predator model's head is facing the feeder while ignoring the head orientation. In addition to head orientation, eyes are a cue of predator risk. In the current study, I examined whether or not chickadees and titmice used the presence of eyes of a predator model to determine when to forage for food. Plastic owl models, with their eyes covered or uncovered, were presented to wild flocks of chickadees and titmice. To test whether or not chickadees and titmice would respond to the presence of eyes, the number of seeds taken and the calling behavior of birds were compared between the two types of predator presentations (eyes covered or uncovered). Chickadees and titmice took fewer seeds when the eyes were uncovered than when they were covered. Chickadees also gave significantly more introductory notes, often used in association with the presence of predators or risk, in their calls when the eyes were visible than when the eyes of the predator model were covered. The results indicate that chickadees and titmice can use the presence of eyes on predators to determine predation risk and possibly use eye gaze to determine where a predator is looking.