To forage or hide? Threat-sensitive foraging behaviour in wild, non-reproductive passerine birds

Abstract

Because antipredator behaviours are costly, the threat-sensitive predator avoidance hypothesis predicts that individual animals should express predator-avoidance behaviour proportionally to the perceived threat posed by the predator. Here, we experimentally tested this hypothesis by providing wild passerine birds supplemental food (on a raised feeding platform) at either 1 or 4 m from the edge of forest cover (potential refuge), in either the presence or absence of a nearby simulated predation threat (a sharp-shinned hawk Accipiter striatus model). Compared with the control treatment, we observed proportionally fewer bird visits to the food patch, and the birds took longer to re-emerge from forest refuge and return to feed at the food patch, after the hawk presentation than before it. The observed threat-sensitive latency-to-return response was stronger when the food patch was further away from the nearest refuge. Overall, our results are consistent with the predictions of the threat-sensitive predator avoidance hypothesis in that wild passerine birds (primarily black-capped chickadees Poecile atricapillus) exhibited more intense antipredator behavioural responses with increasing level of apparent threat. The birds were thus sensitive to their local perceived threat of predation and traded-off safety from predation (by refuging) and foraging gains in open habitat in a graded, threat-sensitive manner.

The Effect of Pine Forest Structure on Bird-Mobbing Behavior: From Individual Response to Community Composition

“…Furthermore, the responding birds kept a greater distance from the speaker than they did for the calls of the two all-year residents. These results support the possibility that interspecific responses are genetically coded behavior [50] or conspecific identification [72], along with allopatric response to mobbing calls [48,94]. Yet, most of the responders to P. ater calls were non-resident species.…”

“…The calling sounds were played using a portable speaker, located 1 m away from a tree and 1.5 m up from the ground in a Pistacia lentiscus shrub. The speaker was viewed from a distance using binoculars in 10 min intervals [71,72]. Mobbing experiments included a 10 min playback of each bird species with 15 min break between each playback.…”

“…We recorded responses by the mobbing behavior in 50 m radius from the speaker of each individual with two parameters: distance and time. The distance from the speaker was recorded [52,72] as the response level [73]. We also noted the time of reaction of the first responder [49] because first responders to mobbing subject to greater risk from the predator, since they start to react before mobbing behavior is spread across the surrounding bird community [28,29].…”

Vegetation and predator interactions affect northern bobwhite behavior

“…This result indicates bobwhites are capable of threat‐type detection and threat‐sensitive predator avoidance responses (Helfman ). Evidence for threat‐sensitive behavior has been reported in other taxa such as fish (Brown and Dreier , Wishingrad et al ), passerines (Turney and Godin , Freeberg et al ), and ungulates (Creel et al , Kuijper et al ).…”

“…Vegetation structure can interfere with an animal's ability to receive and interpret visual and auditory cues, impeding their detection of predators and anti‐predator behaviors (Underwood , Metcalfe , Devereux et al ). Vegetation can also improve concealment of prey, thereby reducing the prey's exposure to predators (Lima and Dill , Griesser and Nystrand , Turney and Godin ). Habitat may affect a prey animal's assessment of predation risk and their avoidance behavior such that energetically costly behaviors (e.g., flight) are reserved for only those situations of imminent threat (Whittingham et al , Stears and Shrader ).…”