Spelling suggestions: "subject:"predators recognition""
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Research on cognitive abilities in untrained birdsNÁCAROVÁ, Jana January 2017 (has links)
This study investigates the cues used for predator recognition by wild-living untrained birds great tits (Parus major). The experimental approach is used to test the reaction to the variously modified dummies of sparrowhawk (Accipiter nisus) and pigeon (Columba livia f. domestica) under laboratory conditions. The role of key features (yellow eye, hooked beak and talons), colour and size is tested. The results imply that the presence of raptor-specific features is mostly necessary but not sufficient to recognize predator in the presented dummies. Following research revealed that the part of the variability in response of great tits can be taken on the account of personality.
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Reakce palearktických a nearktických sýkor na sympatrické a alopatrické predátory v krmítkových experimentech: existují regionální rozdíly v rozpoznávání predátorů a hodnocení jejich nebezpečnosti? / Reaction of Palearctic and Nearctic chickadees to sympatric and allopatric predators using feeder experiments: do regional differences in recognition of predators and determination of threat they are posing exist?Lončík, Lukáš January 2014 (has links)
We have examined wild palearctic and nearctic parids in their ability to recognize and assess a threat level of sympatric and allopatric predators. The study was conducted in Prague, Czech republic, on great tits (Parus major) and blue tits (Parus caeruleus) during the winter of 2013, and the following year in the city of Calgary, Canada, on black-capped chickadees (Poecile atricapillus). Three species of falcons (merlin (Falco columbarius), common kestrel (Falco tinnunculus) and american kestrel (Falco sparverius)), were chosen, two of which were sympatric and one was allopatric to the studied parid species in each area. We have also tested their reaction to nest predators magpies (eurasian magpie (Pica pica), black-billed magpie (Pica hudsonia)). Using two ground feeders in the winter time, we gave parids a choice between a feeder with either one of the three dummies of falcons, or a magpie, and a feeder with a dummy of either a hawk (the most dangerous predator of small birds) or a dove (a harmless bird of the same size as falcons). As a control we have only used sympatric species: eurasian sparrowhawk (Accipiter nisus), Cooper's hawk (Acipiter cooperii), eurasian collared dove (Streptopelia decaocto) and mourning dove (Zenaida macroura). Results from the city of Calgary did not produce any...
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Learning to recognize and generalize the sight of predators and non-predators : does turbidity impair recognition?2013 February 1900 (has links)
To be successful, individuals that are susceptible to predation have to optimize the trade-offs between predator avoidance and other fitness related activities such as foraging or reproduction. One challenge for prey is to identify which species pose a threat and should be avoided, and which species should be ignored. The goal of this study was to investigate whether minnows can generalize recognition of predators and non-predators using visual cues. I conducted experiments in both clear and turbid conditions to test whether the level of turbidity affects the quality of visual information available to the prey and hence the ability of prey to generalize. Latent inhibition and learned irrelevance are mechanisms of learning that can be used by prey to recognize stimuli as non-risky. Repeated exposure to an unknown stimulus in the absence of risk leads to the stimulus being categorized as non-risky. Fathead minnows were pre-exposed to the sight of brook trout or control water to provide minnows the opportunity to learn to recognize the trout as a non-predator. Following this the fish were conditioned with alarm cues (AC) to the sight of each predator paired and then their responses to the sight of brook trout, rainbow trout, and yellow perch were tested either in clear or turbid water. In clear water, minnows conditioned to recognize one of the trout species generalized their response to the other species. However, when the minnows were pre-exposed to the sight of a brook trout, they were inhibited from subsequently recognizing the sight of brook trout as threat and generalized this non-predator recognition to the sight of rainbow trout but not to yellow perch.
In turbid water, however, minnows that were pre-exposed to the sight of brook trout had impaired responses to all predators while those pre-exposed to water showed an intermediate intensity anti-predator response toward each predator. Overall, my results demonstrate that minnows were able to distinguish between predators and non-predators in the clear environment but turbidity influences the visual information used by minnows and hence impaired the minnow’s ability to recognize and generalize the sight of predators and non-predator species.
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Role znaků a geonů v rozpoznávání predátorů netrénovanými ptáky: obrana hnízdaNOVÁKOVÁ, Nela January 2016 (has links)
I examined two main hypotheses proposed for the object recognition: Particulate feature theory and recognition by components using methods of behavioural ecology, namely nest defence. We tested reactions of Red-backed shrike (Lanius collurio) to dummies of Common kestrel (Falco tinnunculus) with scrambled body parts (head above, in the middle and at the bottom). Our result suggested that birds don't recognize the kestrel in the dummies with inappropriately placed head. Therefore, our results support rather the theory recognition by components.
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Vliv predátora na ostražitost sýkor navštěvujících krmítko / The effect of a predator occurrence on vigilance of tits visiting the winter feederTichá, Irena January 2011 (has links)
This thesis evaluates the vigilance parameters of two species of tits affected by the presence of a predator in wintertime. During preferential experiments, tits have had a choice of two feeders in the vicinity of the installed dummy predator. For that purpose was used a dummy sparrowhawk, incomplete or occluded sparrowhawk torsos, and harmless pigeon. It is known that the tits are able to recognize dangerousness presented by the dummy, and according to expected risk dare to visit one of the feeders. It leads to a question whether the tits are somehow influenced by the presence of the dummies, and if so, how specifically are they influenced. It turned out, that the tits in presence of a dangerous dummy significantly increased their vigilance. Both observed species at the feeders behave oppositely. Behaviour of all the birds at the feeder is also affected by their total count at the precise moment and by the presence of a dummy at the other feeder.
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Využití "Amodal completion" při rozpoznávání predátorů: vliv na riskování / The use of amodal completion inpredators recognition: effect on risk takingSedláčková, Kristýna January 2012 (has links)
Amodal completion enables animals (birds, mammals, but also fish) to perceive partly occluded objects as whole. Most of the studies focusing on the occlusion phenomenon were carried out in a laboratory and were based on either operant conditioning or filial imprinting techniques. This study concentrates on behavior of untrained animals in their natural habitat. Pairwise preferential experiments were used to reveal responses of tits (the great tit, Parus major; the blue tit, Cyanistes caeruleus; the marsh tit, Poecile palustris) to two dummies placed near an experimental and an alternative feeder. The dummies used were the complete dummy of a sparrowhawk and a pigeon, and partly occluded (the lower or upper torso hidden in shrubs) and amputated (only lower or upper torso on the perch) models of sparrowhawks - 15 combinations altogether. The tits considered all variants of torsos to be predators. The great tit and the blue tit perceived the model with occluded lower torso as more dangerous than the one with amputated lower torso. Such discrimination between these torsos requires the ability of amodal completion. The great tit also confirms this ability as it regarded the complete sparrowhawk and the model with occluded lower torso as equally dangerous. In the remaining cases, the number of arrivals...
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Threat-sensitive learning and generalization of predator recognition by aquatic vertebratesFerrari, Maud C.O. 29 January 2009
Many prey species lack innate recognition of their potential predators. Hence, learning is required for them to recognize and respond to predation threats. When wild-caught, these same species may show amazing sophistication in their responses to predator cues. They are able to adjust the intensity of their antipredator responses to a particular predator according to the degree of threat posed by that predator. This ability is therefore acquired through learning. While many studies have shown that prey can learn to respond to predator cues through different learning modes, little is known about what the prey are actually learning. The results presented in this thesis show that learned predator recognition goes beyond the simple labelling of predators as dangerous. Using fathead minnows (Pimephales promelas), woodfrog (Rana sylvatica) tadpoles and boreal chorus frog (Pseudacris maculata) tadpoles, I demonstrated that a one time learning event, either through pairing with alarm cues or through social learning, was enough for prey to learn the level of threat associated with the novel predator cues. I showed that the level of danger associated with the predator cues was determined by the concentration of alarm cues when learning through pairing of alarm cues, or by the intensity of antipredator response displayed by the tutors and by the tutor-to-observer ratio when learning occurred through cultural transmission. Moreover, when subsequently exposed to predator cues, prey adjusted their antipredator responses according to the change in concentration of predator cues between the learning event and the subsequent exposure. Prey displayed stronger antipredator responses when exposed to higher concentrations of predator cues and vice versa. When minnows were provided with conflicting information about the danger level associated with a predator, they displayed a safety strategy and used the most recent information available to respond to predation threats. On a longer time scale, the data also suggest that woodfrog tadpoles are able to learn to respond to predation threats according to the risk posed by the predator at different times of day. Finally, I showed that prey learn to recognize particular characteristics of predators and can generalize their antipredator responses to novel species sharing those characteristics. However, generalization of predator recognition is dependent on the level of risk associated with the predator. Threat-sensitive learning is an extremely complex process shaped by the millions of years of selection imposed by predators on prey.
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Threat-sensitive learning and generalization of predator recognition by aquatic vertebratesFerrari, Maud C.O. 29 January 2009 (has links)
Many prey species lack innate recognition of their potential predators. Hence, learning is required for them to recognize and respond to predation threats. When wild-caught, these same species may show amazing sophistication in their responses to predator cues. They are able to adjust the intensity of their antipredator responses to a particular predator according to the degree of threat posed by that predator. This ability is therefore acquired through learning. While many studies have shown that prey can learn to respond to predator cues through different learning modes, little is known about what the prey are actually learning. The results presented in this thesis show that learned predator recognition goes beyond the simple labelling of predators as dangerous. Using fathead minnows (Pimephales promelas), woodfrog (Rana sylvatica) tadpoles and boreal chorus frog (Pseudacris maculata) tadpoles, I demonstrated that a one time learning event, either through pairing with alarm cues or through social learning, was enough for prey to learn the level of threat associated with the novel predator cues. I showed that the level of danger associated with the predator cues was determined by the concentration of alarm cues when learning through pairing of alarm cues, or by the intensity of antipredator response displayed by the tutors and by the tutor-to-observer ratio when learning occurred through cultural transmission. Moreover, when subsequently exposed to predator cues, prey adjusted their antipredator responses according to the change in concentration of predator cues between the learning event and the subsequent exposure. Prey displayed stronger antipredator responses when exposed to higher concentrations of predator cues and vice versa. When minnows were provided with conflicting information about the danger level associated with a predator, they displayed a safety strategy and used the most recent information available to respond to predation threats. On a longer time scale, the data also suggest that woodfrog tadpoles are able to learn to respond to predation threats according to the risk posed by the predator at different times of day. Finally, I showed that prey learn to recognize particular characteristics of predators and can generalize their antipredator responses to novel species sharing those characteristics. However, generalization of predator recognition is dependent on the level of risk associated with the predator. Threat-sensitive learning is an extremely complex process shaped by the millions of years of selection imposed by predators on prey.
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The impact of isolation from mammalian predators on the anti-predator behaviours of the North Island robin (Petroica longipes) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Auckland, New ZealandWhitwell, Sarah Margaret January 2009 (has links)
Conservation in New Zealand has begun to focus heavily on the restoration of degraded mainland ecosystems and the reintroduction of native species that have become locally extinct. In many cases the individuals that are selected for reintroduction are harvested from ‘mammal-free’ offshore islands. This thesis examines the effects of isolation from mammalian predators on the predator avoidance behaviours and predator recognition abilities of New Zealand birds using the North Island robin as a model. It also investigates whether any effects of isolation from mammalian predators has a lasting impact on mainland populations founded by individuals from offshore islands. Nest site selection behaviours were compared across three populations that are exposed to different suites of predators and have differing translocation histories; Benneydale, Tiritiri Matangi and Wenderholm. Point height intercept and point-centred quarter surveys were used to compare habitat availability between the sites and to compare nest sites with the available habitat. Eight nest characteristic variables were also compared across the three sites using a principle component analysis. Benneydale nests were located higher in the trees and were more concealed than nests at the other two sites. Nests on Tiritiri Matangi were supported by large numbers of thin branches and were located toward the periphery of the nest tree. Unfortunately these differences are very difficult to interpret due to a high degree of variation in the habitat types present at the three sites. The anti-predator behaviours initiated in response to a model stoat, model morepork and control were used to test the ability of nesting robins to recognise the threat that each of these treatments might pose to nest success. Behavioural variables were compared between Benneydale, Tiritiri Matangi and Wenderholm using a response intensity scoring system and a principle component analysis. The results indicated that isolation from mammalian predators on Tiritiri Matangi has suppressed the ability of robins on the island to recognise the predatory threat posed by a stoat. They also suggest that the intense mammal control carried out at Wenderholm may have inhibited the ability of local robins to produce strong anti-predator responses when faced with a stoat.
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The impact of isolation from mammalian predators on the anti-predator behaviours of the North Island robin (Petroica longipes) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Auckland, New ZealandWhitwell, Sarah Margaret January 2009 (has links)
Conservation in New Zealand has begun to focus heavily on the restoration of degraded mainland ecosystems and the reintroduction of native species that have become locally extinct. In many cases the individuals that are selected for reintroduction are harvested from ‘mammal-free’ offshore islands. This thesis examines the effects of isolation from mammalian predators on the predator avoidance behaviours and predator recognition abilities of New Zealand birds using the North Island robin as a model. It also investigates whether any effects of isolation from mammalian predators has a lasting impact on mainland populations founded by individuals from offshore islands. Nest site selection behaviours were compared across three populations that are exposed to different suites of predators and have differing translocation histories; Benneydale, Tiritiri Matangi and Wenderholm. Point height intercept and point-centred quarter surveys were used to compare habitat availability between the sites and to compare nest sites with the available habitat. Eight nest characteristic variables were also compared across the three sites using a principle component analysis. Benneydale nests were located higher in the trees and were more concealed than nests at the other two sites. Nests on Tiritiri Matangi were supported by large numbers of thin branches and were located toward the periphery of the nest tree. Unfortunately these differences are very difficult to interpret due to a high degree of variation in the habitat types present at the three sites. The anti-predator behaviours initiated in response to a model stoat, model morepork and control were used to test the ability of nesting robins to recognise the threat that each of these treatments might pose to nest success. Behavioural variables were compared between Benneydale, Tiritiri Matangi and Wenderholm using a response intensity scoring system and a principle component analysis. The results indicated that isolation from mammalian predators on Tiritiri Matangi has suppressed the ability of robins on the island to recognise the predatory threat posed by a stoat. They also suggest that the intense mammal control carried out at Wenderholm may have inhibited the ability of local robins to produce strong anti-predator responses when faced with a stoat.
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