The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Christopher N. Templeton - One of the best experts on this subject based on the ideXlab platform.
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Sparrowhawk movement calling and presence of dead conspecifics differentially impact blue tit cyanistes caeruleus vocal and behavioral mobbing responses
Behavioral Ecology and Sociobiology, 2017Co-Authors: Nora V. Carlson, Helen M. Pargeter, Christopher N. TempletonAbstract:Many animals alter their anti-predator behavior in accordance to the threat level of a predator. While much research has examined variation in mobbing responses to different predators, few studies have investigated how anti-predator behavior is affected by changes in a predator’s own state or behavior. We examined the effect of Sparrowhawk (Accipiter nisus) behavior on the mobbing response of wild blue tits (Cyanistes caeruleus) using robotic taxidermy Sparrowhawks. We manipulated whether the simulated predator moved its head, produced vocalizations, or held a taxidermy blue tit in its talons. When any Sparrowhawk model was present, blue tits decreased foraging and increased anti-predator behavior and vocalizations. Additionally, each manipulation of the model predator’s state (moving, vocalizing, or the presence of a dead conspecific) impacted different types of blue tit anti-predator behavior and vocalizations. These results indicate that different components of mobbing vary according to the specific state of a given predator—beyond its presence or absence—and suggest that each might play a different role in the overall mobbing response. Last, our results indicate that using more life-like predator stimuli—those featuring simple head movements and audio playback of vocalizations—changes how prey respond to the predator; these ‘robo-raptor’ models provide a powerful tool to provide increased realism in simulated predator encounters without sacrificing experimental control. Anti-predatory behavior is often modulated by the threat level posed by a particular predator. While much research has tested how different types of predators change prey behavior, few experiments have examined how predator behavior affects anti-predatory responses of prey. By experimentally manipulating robotic predators, we show that blue tits not only respond to the presence of a Sparrowhawk, by decreasing feeding and increasing anti-predator behavior and vocalizations, but that they vary specific anti-predator behaviors when encountering differently behaving predators (moving, vocalizing, or those with captured prey), suggesting that prey pay attention to their predators’ state and behavior.
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Sparrowhawk movement, calling, and presence of dead conspecifics differentially impact blue tit (Cyanistes caeruleus) vocal and behavioral mobbing responses
Behavioral Ecology and Sociobiology, 2017Co-Authors: Nora V. Carlson, Helen M. Pargeter, Christopher N. TempletonAbstract:Many animals alter their anti-predator behavior in accordance to the threat level of a predator. While much research has examined variation in mobbing responses to different predators, few studies have investigated how anti-predator behavior is affected by changes in a predator’s own state or behavior. We examined the effect of Sparrowhawk ( Accipiter nisus ) behavior on the mobbing response of wild blue tits ( Cyanistes caeruleus ) using robotic taxidermy Sparrowhawks. We manipulated whether the simulated predator moved its head, produced vocalizations, or held a taxidermy blue tit in its talons. When any Sparrowhawk model was present, blue tits decreased foraging and increased anti-predator behavior and vocalizations. Additionally, each manipulation of the model predator’s state (moving, vocalizing, or the presence of a dead conspecific) impacted different types of blue tit anti-predator behavior and vocalizations. These results indicate that different components of mobbing vary according to the specific state of a given predator—beyond its presence or absence—and suggest that each might play a different role in the overall mobbing response. Last, our results indicate that using more life-like predator stimuli—those featuring simple head movements and audio playback of vocalizations—changes how prey respond to the predator; these ‘robo-raptor’ models provide a powerful tool to provide increased realism in simulated predator encounters without sacrificing experimental control. Significance statement Anti-predatory behavior is often modulated by the threat level posed by a particular predator. While much research has tested how different types of predators change prey behavior, few experiments have examined how predator behavior affects anti-predatory responses of prey. By experimentally manipulating robotic predators, we show that blue tits not only respond to the presence of a Sparrowhawk, by decreasing feeding and increasing anti-predator behavior and vocalizations, but that they vary specific anti-predator behaviors when encountering differently behaving predators (moving, vocalizing, or those with captured prey), suggesting that prey pay attention to their predators’ state and behavior.
I Newton - One of the best experts on this subject based on the ideXlab platform.
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Latitudinal variation in the body‐size of Sparrowhawks Accipiter nisus within Britain
Ibis, 2008Co-Authors: I. Wyllie, I NewtonAbstract:On the basis of Sparrowhawks Accipiter nisus found dead in various parts of Britain during 1979–1991. wing-length was found to provide the most reliable index of overall body-size because it gave the best and most consistent correlations with five other measures of body-size. A marked latitudinal trend in the body-size of Sparrowhawks was found within Britain, with birds of each sex and age group increasing in size from south to north, in line with Bergmann's Rule. For each successive degree of latitude (approximately 110 km), wing-length increased by an average of 0.86 mm in adult males and O.75 mm in adult females. No obvious west-east trend in body-size was found within Britain.
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Effects of dieldrin on population growth rates of Sparrowhawks 1963–1986
Journal of Applied Ecology, 2000Co-Authors: Richard M. Sibly, I Newton, C H WalkerAbstract:Summary 1. A recent reappraisal of the evidence of the effects of cyclodiene insecticides on Sparrowhawks Accipiter nisus and kestrels Falco tinnunculus in Britain suggested that during 1963–75 at least 29% of Sparrowhawks found in an eastern area of high cyclodiene use died directly from dieldrin poisoning, compared with only 6% in a more western area of low cyclodiene use. Here, these data are used in a life-history analysis of the quantitative effects of dieldrin on some British Sparrowhawk populations. Where necessary, life-history parameters were taken from two British study populations, one stable and one increasing. 2. Four scenarios were analysed. In scenario 1, reflecting high cyclodiene use, the effect of dieldrin poisoning was to increase the instantaneous mortality rate by 0·20 year−1. Life-history modelling revealed that this would have produced a population decline of 20% year−1 (λ = 0·82 year−1). Adding in possible sublethal effects of dieldrin produced an even more serious decline of 60% year−1 (scenario 2). 3. Data suggested that population growth rate increased linearly as population density decreased. A simple analysis omitting age structure suggested that density-dependence would not save the scenario 2 population from extinction, but would hold the scenario 1 population at 64% of its former value (scenario 3). The available data suggest the former is correct, i.e. sublethal effects were important during the population decline. 4. During 1976–82, when use of cyclodienes was reduced, the effect of dieldrin poisoning on Sparrowhawks in eastern Britain was estimated as an increased instantaneous mortality rate of 0·05 year−1. This is low enough to allow population recovery from low density, at a rate of 13% year−1 (scenario 4). 5. Another way to analyse the effects of dieldrin (or any other additional density-independent mortality agent) is to ask what reductions in fecundity or survival could be sustained long-term by an otherwise increasing population. The data suggested that the population could withstand a halving of fecundity (from 2·07 to 1·035) or a reduction of adult survival from 0·74 to 0·55. 6. The analyses presented are based on field data, and are thought to be reasonably realistic of the true impacts of dieldrin and other cyclodienes on British Sparrowhawks.
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Effects of Cyclodiene Insecticides on the Sparrowhawk (Accipiter Nisus) in Britain – a Reappraisal of the Evidence
Ecotoxicology, 1998Co-Authors: C H Walker, I NewtonAbstract:Cyclodiene insecticides were introduced in Britain in the mid-1950s, after which there was a rapid decline of Sparrowhawk populations in agricultural areas associated with the lethal toxicity of these compounds. Subsequently the recovery of Sparrowhawk populations was studied in different areas of Britain following the ban on dieldrin seed dressings in 1975. Frequency distribution diagrams of dieldrin residues in Sparrowhawk livers were constructed for different geographical areas over specified periods. During 1963–1975, biphasic distributions were found, with some 50% of the entire sample contained within a second peak of geometric mean 20 p.p.m. in an eastern area where cylodiene exposure was greatest and populations were most depressed. A similar second peak was found in a sample from another area where the cyclodiene exposure was less, although it only represented 5% of the individuals found dead. These individuals with high dieldrin levels had evidently received lethal doses of insecticide. In a sample from the eastern area taken during 1976–1982, the peak at 20 p.p.m. had virtually disappeared, to be replaced by another peak centred on 4.8 p.p.m. This latter peak may have represented individuals dying as a consequence of sublethal neurotoxic effects. The distribution diagrams for 1983–1986 showed single peaks of dieldrin centring on 0.55–0.75 p.p.m., with no clear evidence of other peaks which might represent poisoned individuals. By this time, the populations in both areas had either fully recovered or were rapidly recovering.
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effects of cyclodiene insecticides on the Sparrowhawk accipiter nisus in britain a reappraisal of the evidence
Ecotoxicology, 1998Co-Authors: C H Walker, I NewtonAbstract:Cyclodiene insecticides were introduced in Britain in the mid-1950s, after which there was a rapid decline of Sparrowhawk populations in agricultural areas associated with the lethal toxicity of these compounds. Subsequently the recovery of Sparrowhawk populations was studied in different areas of Britain following the ban on dieldrin seed dressings in 1975. Frequency distribution diagrams of dieldrin residues in Sparrowhawk livers were constructed for different geographical areas over specified periods. During 1963–1975, biphasic distributions were found, with some 50% of the entire sample contained within a second peak of geometric mean 20 p.p.m. in an eastern area where cylodiene exposure was greatest and populations were most depressed. A similar second peak was found in a sample from another area where the cyclodiene exposure was less, although it only represented 5% of the individuals found dead. These individuals with high dieldrin levels had evidently received lethal doses of insecticide. In a sample from the eastern area taken during 1976–1982, the peak at 20 p.p.m. had virtually disappeared, to be replaced by another peak centred on 4.8 p.p.m. This latter peak may have represented individuals dying as a consequence of sublethal neurotoxic effects. The distribution diagrams for 1983–1986 showed single peaks of dieldrin centring on 0.55–0.75 p.p.m., with no clear evidence of other peaks which might represent poisoned individuals. By this time, the populations in both areas had either fully recovered or were rapidly recovering.
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Mortality from the pesticides aldrin and dieldrin in British Sparrowhawks and Kestrels
Ecotoxicology, 1992Co-Authors: I Newton, I. Wyllie, A. AsherAbstract:Among 1029 dead Sparrowhawks and 1055 dead Kestrels from various parts of Britain that were examined over the period 1963–90, the main causes of death were (a) collisions of various kinds (b) starvation or disease and (c) organochlorine poisoning. The main chemical which caused poisoning was HEOD, derived from the insecticides aldrin and dieldrin. Other deaths were attributed to poisoning by DDE (the main metabolite of the insecticide DDT) and by HE (heptachlor epoxide, derived from the insecticide heptachlor). Sparrowhawks whose deaths were attributed to HEOD poisoning contained 5–85 µg g^−1 HEOD in their livers (wet weight), while Kestrels contained 6–99 µg g^−1 HEOD. Such birds were typically lighter in weight than collision victims, but heavier than starved or diseased birds. In the period 1963–75, HEOD probably accounted for about 50% of all recorded Sparrowhawk deaths and 39% of all recorded Kestrel deaths in eastern arable districts, but a smaller proportion elsewhere. Geographical variation in the proportion of deaths attributed to HEOD paralleled variation in the proportion of land devoted to arable crops on which aldrin and dieldrin were mainly used. It also paralleled variation in the extent of population decline in these species. Moreover, the proportion of deaths attributed to HEOD declined between 1963–75 and 1976–86, following a marked reduction in aldrin-dieldrin use, and fell to nil in 1987–90, when aldrin and dieldrin were withdrawn altogether. Over this period, the populations of both species recovered from a decline which occurred in the late 1950s, when aldrin-dieldrin were first introduced.
Anders Pape Moller - One of the best experts on this subject based on the ideXlab platform.
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alarm call based discrimination between common cuckoo and eurasian Sparrowhawk in a chinese population of great tits
Ethology, 2017Co-Authors: Jiangping Yu, Xiaoying Xing, Yunlei Jiang, Wei Liang, Haitao Wang, Anders Pape MollerAbstract:Morphological resemblance of the common cuckoo Cuculus canorus to the Eurasian Sparrowhawk Accipiter nisus has been regarded as an example of predator mimicry. Common hosts could distinguish parasites as the result of coevolution, while rare hosts or non-hosts may mistake cuckoos for hawks because rare hosts or non-hosts behave similarly when faced with these two species. Birds usually produce alarm calls in addition to showing behavioral responses when in danger. However, previous studies of identification by rare hosts or non-hosts of Sparrowhawks usually lacked experimental evidence of alarm calls. Great tits Parus major, a rare cuckoo host, perform similar behaviors and usually produce alarm calls in response to Sparrowhawks and common cuckoos. Here, we tested whether great tits could distinguish common cuckoo from Sparrowhawk based on analysis of their alarm calls and the effects of playback of alarm calls on conspecific behavior. Previous studies showed that great tits have a complex communication system that conveys information about predators, and they could perform different kinds of response behavior to different alarm calls. If great tits have not made the ability to distinguish between common cuckoo and Sparrowhawk, then their acoustic responses to these two species and their response behaviors in playback experiments should be similar. Specimens of a common cuckoo (parasite), a Sparrowhawk (predator) and an Oriental turtle dove Streptopelia orientalis (harmless control) were used to elicit and subsequently record the response behavior and alarm calls of great tits. There was no significant difference in behavioral response among great tits when exposed to the dummy of cuckoo, Sparrowhawk and dove. In contrast, they differed significantly in alarm calls. Great tits produced more notes per call that contained increasing D-type and decreasing I-type notes when responding to Sparrowhawk as compared to cuckoo or dove. In playback experiments, we found that great tits responded more strongly to great tit hawk than to great tit cuckoo or great tit dove alarm calls. Our study suggests that great tits are able to distinguish Sparrowhawks from common cuckoos and convey relevant information in alarm calls by adjusting the number and combinations of notes of a single call type.
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Alarm call‐based discrimination between common cuckoo and Eurasian Sparrowhawk in a Chinese population of great tits
Ethology, 2017Co-Authors: Jiangping Yu, Xiaoying Xing, Yunlei Jiang, Wei Liang, Haitao Wang, Anders Pape MollerAbstract:Morphological resemblance of the common cuckoo Cuculus canorus to the Eurasian Sparrowhawk Accipiter nisus has been regarded as an example of predator mimicry. Common hosts could distinguish parasites as the result of coevolution, while rare hosts or non-hosts may mistake cuckoos for hawks because rare hosts or non-hosts behave similarly when faced with these two species. Birds usually produce alarm calls in addition to showing behavioral responses when in danger. However, previous studies of identification by rare hosts or non-hosts of Sparrowhawks usually lacked experimental evidence of alarm calls. Great tits Parus major, a rare cuckoo host, perform similar behaviors and usually produce alarm calls in response to Sparrowhawks and common cuckoos. Here, we tested whether great tits could distinguish common cuckoo from Sparrowhawk based on analysis of their alarm calls and the effects of playback of alarm calls on conspecific behavior. Previous studies showed that great tits have a complex communication system that conveys information about predators, and they could perform different kinds of response behavior to different alarm calls. If great tits have not made the ability to distinguish between common cuckoo and Sparrowhawk, then their acoustic responses to these two species and their response behaviors in playback experiments should be similar. Specimens of a common cuckoo (parasite), a Sparrowhawk (predator) and an Oriental turtle dove Streptopelia orientalis (harmless control) were used to elicit and subsequently record the response behavior and alarm calls of great tits. There was no significant difference in behavioral response among great tits when exposed to the dummy of cuckoo, Sparrowhawk and dove. In contrast, they differed significantly in alarm calls. Great tits produced more notes per call that contained increasing D-type and decreasing I-type notes when responding to Sparrowhawk as compared to cuckoo or dove. In playback experiments, we found that great tits responded more strongly to great tit hawk than to great tit cuckoo or great tit dove alarm calls. Our study suggests that great tits are able to distinguish Sparrowhawks from common cuckoos and convey relevant information in alarm calls by adjusting the number and combinations of notes of a single call type.
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barn swallows hirundo rustica differentiate between common cuckoo and Sparrowhawk in china alarm calls convey information on threat
Behavioral Ecology and Sociobiology, 2016Co-Authors: Jiangping Yu, Xiaoying Xing, Haitao Wang, Anders Pape Moller, Longwu Wang, Canchao Yang, Wei LiangAbstract:Morphological mimicry of Sparrowhawks Accipiter spp. by cuckoos acts to deceive hosts and thus promotes parasitism by cuckoos. Recent studies have suggested that common hosts are able to identify parasites and make special alarm calls as the result of co-evolution between hosts and brood parasites. Previous studies showed that barn swallows Hirundo rustica could distinguish between common cuckoo Cuculus canorus and Sparrowhawk Accipiter nisus in Denmark, but seemed unable to make this distinction in China. However, these previous studies did not investigate vocal responses in terms of alarm calls. We tested whether barn swallows, which are regular hosts of the common cuckoo in China, could distinguish between the common cuckoo and Sparrowhawk in China. In Heilongjiang, in the presence of the cuckoo and, in Hainan, in its absence, we used dummies of common cuckoo, Sparrowhawk, and Oriental turtle dove Streptopelia orientalis (neutral control) to induce and record alarm calls that were used to estimate response to playbacks. Barn swallows responded more strongly to playbacks of swallow hawk alarm calls than in response to swallow cuckoo or swallow dove alarm calls. Given that alarm calls conveyed information about the presence of potential threats, our study showed that barn swallows from both study regions in China were able to distinguish between common cuckoo and Sparrowhawk and respond accordingly in their vocal behavior.
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predator prey relationships in a changing environment the case of the Sparrowhawk and its avian prey community in a rural area
Journal of Animal Ecology, 2009Co-Authors: Alexandre Millon, Jan Tottrup Nielsen, Vincent Bretagnolle, Anders Pape MollerAbstract:Summary 1. Changes in community composition are expected to entail cascading effects at different trophic levels within a food web. However, empirical evidence on the impact of changes in prey communities on the population dynamics of generalist predators, and on the extent of possible feedback processes, remains scarce. 2. We analysed the dynamics of a generalist predator, the European Sparrowhawk Accipiter nisus L., in a rural area of Northern Denmark. Over a 20-year period, the diet of the predator has been thoroughly assessed ( > 30 000 identified prey items) and quantitative information about its avian prey community, based on standard breeding bird surveys, has revealed significant trends for several passerine species, although the overall prey biomass available remained stable. 3. The growth rate of the Sparrowhawk breeding population was negatively related to the previous Sparrowhawk density and to winter temperature, but was positively related to available prey biomass. Contrary to expectations for a generalist predator, Sparrowhawks seemed to be predominantly sensitive to changes in the cumulative abundance of their two main prey species, the skylark Alauda arvensis L. and the blackbird Turdus merula L., but less so to changes in the wider prey community. 4. In demographic terms, the two-phase Sparrowhawk dynamic recorded here (a recovery following an initial decrease) was mainly driven by recruitment of yearling females into the breeding population rather than by variation in the apparent survival of breeding females. 5. Our findings emphasize that changes in the composition of a prey community, affected by environmental changes, impacted population dynamics of a generalist predator. Finally, we found conditions that might enable apparent competition between blackbirds and song thrushes Turdus philomelos L. to occur. High blackbird abundance, maintaining Sparrowhawks at a relatively high density may, in turn, push song thrushes into a predator pit.
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effects of food abundance density and climate change on reproduction in the Sparrowhawk accipiter nisus
Oecologia, 2006Co-Authors: Jan Tottrup Nielsen, Anders Pape MollerAbstract:The reproductive success of predators depends on abiotic environmental conditions, food abundance and population density, and food abundance, density and their interactions may respond to changes in climatic conditions. Timing of reproduction by five of the eight numerically most common prey of the Sparrowhawk Accipiter nisus advanced significantly since 1971, during a period of temperature increase. There was no evidence that mean laying date or any other reproductive parameter of Sparrowhawks changed consistently during the study period 1977-1997. Laying date advanced and percentage of unsuccessful female Sparrowhawks decreased with beech mast in the current year, an index of food abundance for avian prey. Mean laying date of Sparrowhawks was advanced in warmer springs, and although mean clutch size was not larger in warm than in cold springs, mean brood size of successful pairs and breeding success increased in such springs, showing that Sparrowhawks enjoyed a fitness gain when reproducing early. The timing of Sparrowhawk reproduction with respect to the peak in abundance of fledgling prey increased, from a good match between mean timing of fledging by prey and maximum demand for food by the predator in 1977, to reproduction occurring later than the peak in fledging prey availability in 1997. The size of the breeding population of Sparrowhawks was not predicted by mean spring temperature, the size of the breeding population the previous year or beech mast crop. The size of the post-breeding population was predicted by size of the breeding and post-breeding population the previous year and by the proportion of unsuccessful females the current year. These findings imply that Sparrowhawks did not respond to change in climate, although climate changed the timing of reproduction by the main prey species.
Helen M. Pargeter - One of the best experts on this subject based on the ideXlab platform.
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Sparrowhawk movement calling and presence of dead conspecifics differentially impact blue tit cyanistes caeruleus vocal and behavioral mobbing responses
Behavioral Ecology and Sociobiology, 2017Co-Authors: Nora V. Carlson, Helen M. Pargeter, Christopher N. TempletonAbstract:Many animals alter their anti-predator behavior in accordance to the threat level of a predator. While much research has examined variation in mobbing responses to different predators, few studies have investigated how anti-predator behavior is affected by changes in a predator’s own state or behavior. We examined the effect of Sparrowhawk (Accipiter nisus) behavior on the mobbing response of wild blue tits (Cyanistes caeruleus) using robotic taxidermy Sparrowhawks. We manipulated whether the simulated predator moved its head, produced vocalizations, or held a taxidermy blue tit in its talons. When any Sparrowhawk model was present, blue tits decreased foraging and increased anti-predator behavior and vocalizations. Additionally, each manipulation of the model predator’s state (moving, vocalizing, or the presence of a dead conspecific) impacted different types of blue tit anti-predator behavior and vocalizations. These results indicate that different components of mobbing vary according to the specific state of a given predator—beyond its presence or absence—and suggest that each might play a different role in the overall mobbing response. Last, our results indicate that using more life-like predator stimuli—those featuring simple head movements and audio playback of vocalizations—changes how prey respond to the predator; these ‘robo-raptor’ models provide a powerful tool to provide increased realism in simulated predator encounters without sacrificing experimental control. Anti-predatory behavior is often modulated by the threat level posed by a particular predator. While much research has tested how different types of predators change prey behavior, few experiments have examined how predator behavior affects anti-predatory responses of prey. By experimentally manipulating robotic predators, we show that blue tits not only respond to the presence of a Sparrowhawk, by decreasing feeding and increasing anti-predator behavior and vocalizations, but that they vary specific anti-predator behaviors when encountering differently behaving predators (moving, vocalizing, or those with captured prey), suggesting that prey pay attention to their predators’ state and behavior.
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Sparrowhawk movement, calling, and presence of dead conspecifics differentially impact blue tit (Cyanistes caeruleus) vocal and behavioral mobbing responses
Behavioral Ecology and Sociobiology, 2017Co-Authors: Nora V. Carlson, Helen M. Pargeter, Christopher N. TempletonAbstract:Many animals alter their anti-predator behavior in accordance to the threat level of a predator. While much research has examined variation in mobbing responses to different predators, few studies have investigated how anti-predator behavior is affected by changes in a predator’s own state or behavior. We examined the effect of Sparrowhawk ( Accipiter nisus ) behavior on the mobbing response of wild blue tits ( Cyanistes caeruleus ) using robotic taxidermy Sparrowhawks. We manipulated whether the simulated predator moved its head, produced vocalizations, or held a taxidermy blue tit in its talons. When any Sparrowhawk model was present, blue tits decreased foraging and increased anti-predator behavior and vocalizations. Additionally, each manipulation of the model predator’s state (moving, vocalizing, or the presence of a dead conspecific) impacted different types of blue tit anti-predator behavior and vocalizations. These results indicate that different components of mobbing vary according to the specific state of a given predator—beyond its presence or absence—and suggest that each might play a different role in the overall mobbing response. Last, our results indicate that using more life-like predator stimuli—those featuring simple head movements and audio playback of vocalizations—changes how prey respond to the predator; these ‘robo-raptor’ models provide a powerful tool to provide increased realism in simulated predator encounters without sacrificing experimental control. Significance statement Anti-predatory behavior is often modulated by the threat level posed by a particular predator. While much research has tested how different types of predators change prey behavior, few experiments have examined how predator behavior affects anti-predatory responses of prey. By experimentally manipulating robotic predators, we show that blue tits not only respond to the presence of a Sparrowhawk, by decreasing feeding and increasing anti-predator behavior and vocalizations, but that they vary specific anti-predator behaviors when encountering differently behaving predators (moving, vocalizing, or those with captured prey), suggesting that prey pay attention to their predators’ state and behavior.
Nora V. Carlson - One of the best experts on this subject based on the ideXlab platform.
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Sparrowhawk movement calling and presence of dead conspecifics differentially impact blue tit cyanistes caeruleus vocal and behavioral mobbing responses
Behavioral Ecology and Sociobiology, 2017Co-Authors: Nora V. Carlson, Helen M. Pargeter, Christopher N. TempletonAbstract:Many animals alter their anti-predator behavior in accordance to the threat level of a predator. While much research has examined variation in mobbing responses to different predators, few studies have investigated how anti-predator behavior is affected by changes in a predator’s own state or behavior. We examined the effect of Sparrowhawk (Accipiter nisus) behavior on the mobbing response of wild blue tits (Cyanistes caeruleus) using robotic taxidermy Sparrowhawks. We manipulated whether the simulated predator moved its head, produced vocalizations, or held a taxidermy blue tit in its talons. When any Sparrowhawk model was present, blue tits decreased foraging and increased anti-predator behavior and vocalizations. Additionally, each manipulation of the model predator’s state (moving, vocalizing, or the presence of a dead conspecific) impacted different types of blue tit anti-predator behavior and vocalizations. These results indicate that different components of mobbing vary according to the specific state of a given predator—beyond its presence or absence—and suggest that each might play a different role in the overall mobbing response. Last, our results indicate that using more life-like predator stimuli—those featuring simple head movements and audio playback of vocalizations—changes how prey respond to the predator; these ‘robo-raptor’ models provide a powerful tool to provide increased realism in simulated predator encounters without sacrificing experimental control. Anti-predatory behavior is often modulated by the threat level posed by a particular predator. While much research has tested how different types of predators change prey behavior, few experiments have examined how predator behavior affects anti-predatory responses of prey. By experimentally manipulating robotic predators, we show that blue tits not only respond to the presence of a Sparrowhawk, by decreasing feeding and increasing anti-predator behavior and vocalizations, but that they vary specific anti-predator behaviors when encountering differently behaving predators (moving, vocalizing, or those with captured prey), suggesting that prey pay attention to their predators’ state and behavior.
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Sparrowhawk movement, calling, and presence of dead conspecifics differentially impact blue tit (Cyanistes caeruleus) vocal and behavioral mobbing responses
Behavioral Ecology and Sociobiology, 2017Co-Authors: Nora V. Carlson, Helen M. Pargeter, Christopher N. TempletonAbstract:Many animals alter their anti-predator behavior in accordance to the threat level of a predator. While much research has examined variation in mobbing responses to different predators, few studies have investigated how anti-predator behavior is affected by changes in a predator’s own state or behavior. We examined the effect of Sparrowhawk ( Accipiter nisus ) behavior on the mobbing response of wild blue tits ( Cyanistes caeruleus ) using robotic taxidermy Sparrowhawks. We manipulated whether the simulated predator moved its head, produced vocalizations, or held a taxidermy blue tit in its talons. When any Sparrowhawk model was present, blue tits decreased foraging and increased anti-predator behavior and vocalizations. Additionally, each manipulation of the model predator’s state (moving, vocalizing, or the presence of a dead conspecific) impacted different types of blue tit anti-predator behavior and vocalizations. These results indicate that different components of mobbing vary according to the specific state of a given predator—beyond its presence or absence—and suggest that each might play a different role in the overall mobbing response. Last, our results indicate that using more life-like predator stimuli—those featuring simple head movements and audio playback of vocalizations—changes how prey respond to the predator; these ‘robo-raptor’ models provide a powerful tool to provide increased realism in simulated predator encounters without sacrificing experimental control. Significance statement Anti-predatory behavior is often modulated by the threat level posed by a particular predator. While much research has tested how different types of predators change prey behavior, few experiments have examined how predator behavior affects anti-predatory responses of prey. By experimentally manipulating robotic predators, we show that blue tits not only respond to the presence of a Sparrowhawk, by decreasing feeding and increasing anti-predator behavior and vocalizations, but that they vary specific anti-predator behaviors when encountering differently behaving predators (moving, vocalizing, or those with captured prey), suggesting that prey pay attention to their predators’ state and behavior.
