Search results for "Alarm signal"
showing 7 items of 7 documents
Predator encounters have spatially extensive impacts on parental behaviour in a breeding bird community.
2016
Predation risk has negative indirect effects on prey fitness, partly mediated through changes in behaviour. Evidence that individuals gather social information from other members of the population suggests that events in a community may impact the behaviour of distant individuals. However, spatially wide-ranging impacts on individual behaviour caused by a predator encounter elsewhere in a community have not been documented before. We investigated the effect of a predator encounter (hawk model presented at a focal nest) on the parental behaviour of pied flycatchers ( Ficedula hypoleuca ), both at the focal nest and at nearby nests different distances from the predator encounter. We show tha…
Age Differences in the Response of Willow Tits (Parus montanus ) to Conspecific Alarm Calls
2003
Predation is an important mortality factor in wintering birds. To counter this, birds produce alarm calls in the presence of predators which serve to warn conspecifics. In social hierarchical bird flocks, adults survive the winter better than juveniles and therefore survival strategies probably vary with social status. This study examined the differential responses to alarm calls by free-living willow tits, Parus montanus, in dominance-structured winter flocks in Finland. To explore the age-dependent differences in response to conspecific alarm calls, a series with three alarm calls was played to focal adults and juveniles while they sat in the middle section of a spruce branch. Immediately…
Chemosensory anxiety signals prime defensive behavior in prepubertal girls
2017
indexation en cours; Chemosensory anxiety signals effectively prime motor responses related to withdrawal behavior, such as the startle reflex, in adult humans. As the reproductive status strongly affects the response to social chemosignals, the current study examined whether chemosensory anxiety signals would augment the startle response in prepubertal children as it does in adults. Using cotton pads, axillary sweat was collected from 28 men while waiting for an important oral examination (anxiety condition), and during ergometer training (sport control condition). Using a constant-flow olfactometer, sweat samples and pure cotton samples (cotton control) were presented to 10 prepubertal gi…
Age-dependent responses to alarm calls depend on foraging activity in Willow TitsPoecile montanus
2011
Survivorship in animals depends on both foraging activities and avoidance of predation, and thus behavioural decisions often reflect a trade-off between predation risk and foraging efficiency. In this experimental study, we compared behavioural responses of free-living adult and juvenile Willow Tits Poecile montanus to a conspecific alarm call in two treatments. The alarm call was played back when a focal bird was either not feeding, or feeding on a sunflower seed on the middle part of a spruce branch. When feeding at the time of the alarm call, juveniles more often stayed motionless or moved shorter distances than adults. Our results suggest that in hierarchical groups, juveniles are force…
Behaviour and neural responses in crucian carp to skin odours from cross-order species
2012
Many teleost species respond with fright reactions to olfactory cues from injured skin of conspecifics, but they may also display responses to skin extracts of heterospecific fish. In the present study, we exposed crucian carp to skin extracts of conspecifics and three cross-order species of fish (brown trout, pike, and perch). Behavioural experiments showed that conspecific skin extracts induced fright reactions in crucian carp; extracts of brown trout induced such behaviour less frequently, while extracts of perch and pike were poor inducers of fright responses. The olfactory bulb is chemo-topically organized, and different sub-sets of neurons respond to functionally related odorants that…
Alarm calling by individual willow tits, Parus montanus
1990
Abstract Alarm responses of wild-captured individual willow tits to model sparrowhawks, Accipiter nisus, flying over a test chamber were studied. Tits did not usually give alarm calls if the apparent predator was passing nearby (at a height of 10 m), while over half of the individuals responded by alarm calling for a more distant predator (40 m). This suggests that alarm calling involves a risk to the caller. Second, there was individual variation in the responses, with older males giving the call more frequently than females or young males. The greater responsiveness of adult males may indicate that different individuals in a flock gain different benefits by warning the others. The tendenc…
Effect of Willow TitPoecile montanusalarm calls on attack rates by Pygmy OwlsGlaucidium passerinum
2013
One suggested anti-predator function of alarm calls is to deliver a message to a predator that it has been detected. Moreover, giving the alarm call could provide a signal to the predator that capturing the individual giving the alarm is more difficult than capturing its silent group members, as the caller is probably the most aware of the predator's location. In an aviary experiment using stuffed dummy Willow Tits Poecile montanus, we assessed whether an authentic alarm call given by Willow Tit affected Pygmy Owl Glaucidium passerinum prey preference. In the experiment, the Owls attacked only the ‘silent’ dummy individuals, suggesting that alarm calling could offer direct fitness benefits …