Change search
Refine search result
12 1 - 50 of 65
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Aronsson, Hanna
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Enquist, Magnus
    Stockholm University, Faculty of Science, Department of Zoology.
    Parental effects on sexual preferences in humans: A web study of attraction to glassesManuscript (preprint) (Other academic)
  • 2.
    Aronsson, Hanna
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Enquist, Magnus
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Parental influences on sexual preferences: The case of attraction to smoking2011In: Journal of Evolutionary Psychology, ISSN 0737-4828, Vol. 9, no 1, p. 21-41Article in journal (Refereed)
    Abstract [en]

    We investigated whether a sexual preference for smoking can be related to past experiences of parental smoking during childhood, as predicted by the theory of sexual imprinting, but also by sexual conditioning theory. In a sample of over 4000 respondents to five Internet surveys on sexual preferences, we found that parental smoking correlates with increased attraction to smoking in self-reported hetero- and homosexual males. Maternal smoking was associated with an increase in attraction to smoking both in hetero- and homosexual males, while paternal smoking was associated with an increase in attraction to smoking only in males who prefer male partners. We could not explain these findings by considering other factors than parental smoking habits, such as possibly biased reporting, indicators of a sexually liberal lifestyle or phenotype matching. Our data are consistent with the hypothesis that sexual preferences are acquired early in life by exposure to stimuli provided by individuals in the child’s environment, such as caregivers. The sex specificity of the parental effect is consistent with sexual imprinting theory but not with conditioning theory.

  • 3. Cresswell, Will
    et al.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Kaby, Ulrika
    Stockholm University, Faculty of Science, Department of Zoology.
    Quinn, John
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Does an opportunistic predator preferentially attack nonvigilant prey?2003In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 66, no 4, p. 643-648Article in journal (Refereed)
    Abstract [en]

    The dilution effect as an antipredation behaviour is the main theoretical reason for grouping in animals and states that all individuals in a group have an equal risk of being predated if equally spaced from each other and the predator. Stalking predators, however, increase their chance of attack success by preferentially targeting nonvigilant individuals, potentially making relative vigilance rates in a group relatively important in determining predation compared with the dilution effect. Many predators, however, attack opportunistically without stalking, when targeting of nonvigilant individuals may be less likely, so that the dilution effect will then be a relatively more important antipredation reason for grouping. We tested whether an opportunistically hunting predator, the sparrowhawk, Accipiter nisus, preferentially attacked vigilant or feeding prey models presented in pairs. We found that sparrowhawks attacked vigilant and feeding mounts at similar frequencies. Our results suggest that individuals should prioritize maximizing group size or individual vigilance dependent on the type of predator from which they are at risk. When the most likely predator is a stalker, individuals should aim to have the highest vigilance levels in a group, and there may be relatively little selective advantage to being in the largest group. In contrast, if the most likely predator is an opportunist, then individuals should simply aim to be in the largest group and can also spend more time foraging without compromising predation risk. For most natural systems this will mean a trade-off between the two strategies dependent on the frequency of attack of each predator type.

  • 4.
    Cresswell, Will
    et al.
    University of St. Andrews, School of Biology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Quinn, John L.
    University of Oxford, Department of Zoology.
    Predator-hunting success and prey vulnerability: quantifying the spatial scale over which lethal and non-lethal effects of predation occur2010In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, ISSN 0021-8790, Vol. 79, no 3, p. 556-562Article in journal (Refereed)
    Abstract [en]

    1. The shape of the function linking predator-attack success rate with distance to predator-concealing cover, or prey refuge, will affect population dynamics, distribution patterns and community trophic structure. Theory predicts that predator-attack success should decline exponentially with distance from predator-concealing cover, resulting in a threshold distance value above which there is little change in risk. Animals should then completely avoid areas of otherwise suitable habitat below this threshold, except when starvation risk exceeds predation risk.

    2. We measured the shape of the function linking attack success with distance from cover in a system of Eurasian Sparrowhawks Accipiter nisus attacking (n = 445) and killing (n = 71) Redshanks Tringa totanus. We then determined if there was a threshold value and whether redshanks avoided areas below this threshold.

    3. Sparrowhawk success rate with distance to predator-concealing cover declined exponentially with a threshold value of approximately 30 m. Redshanks used habitat above the threshold according to profitability and only fed below it, on average, in cold weather when starvation risk can be imminently high. Above about 5°C, 26% of available habitat was avoided.

    4. Our data support the hypothesis that predators create discrete areas with respect to cover that are avoided by prey. Large areas of suitable habitat may be unused, except in times of high starvation risk, when such areas may provide a foraging reserve, with large implications for population distribution and dynamics.

    5. Our results are generated from a system in which predators attack their prey from concealing cover. But in the theoretically identical reverse scenario where the prey animal’s distance from protective cover determines predation risk, such non-lethal effects will be equally important, especially in heavily fragmented landscapes.

  • 5.
    Cresswell, Will
    et al.
    School of Biology, University of St. Andrews.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology. Etologi. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Quinn, John
    Dept. of Zoology, University of Oxford.
    Minderman, Jeroen
    School of Biology and Psychology, University of Newcastle.
    Whitfield, D. P.
    Natural Research, Banchory Business Centre.
    Ringing or colour-banding does not increase predation mortality2007In: Journal of Avian Biology, ISSN 0908-8857, E-ISSN 1600-048X, Vol. 38, no 3, p. 309-316Article in journal (Refereed)
    Abstract [en]

    The use of metal and colour-rings or bands as a means of measuring survival, movements and behaviour in birds is universal and fundamental to testing ecological and evolutionary theories. The practice rests on the largely untested assumption that the rings do not affect survival. However this assumption may not hold for several reasons, for example because the ‘oddity effect’ predicts predators select prey that appear different to their neighbours in order to avoid the ‘confusion effect’. We compared the foraging behaviour and the death rates of redshanks Tringa totanus conspicuously marked with six colour rings and one metal ring each to unmarked birds in a study system, where routinely up to 50% of the total population are killed by avian predators during a winter. If avian predators selectively target and/or have a higher capture success of ringed birds then we would predict the proportion of colour-ringed birds in the population to decline through a winter. The proportion of colour-ringed birds in the population did not change over the course of three separate winters, and in one winter the ratio of marked:unmarked birds found killed by sparrowhawks Accipiter nisus was the same as the ratio of marked birds alive in the population. In the year with largest sample size, power was sufficient to detect a greater than 2.2% difference in predation rate between ringed and unringed groups. The average kill rate difference between ringed and unringed birds across the three winters was less than 1% (0.73±2.2%) suggesting that even if there were differences in predation rate that were not detected because of low statistical power they were extremely small. There were no differences in any foraging measures comparing ringed and unringed birds, suggesting that the rings did not affect the ability of birds to meet their daily energy budgets. The results showed that colour-ringed birds were not preferentially targeted or killed by avian predators, and suggest that the presence of a metal and even several large colour-rings is unlikely to affect behaviour and predation mortality even under extreme selection.

  • 6.
    Enquist, Magnus
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Världshistoria och kulturell evolution2010Other (Other academic)
  • 7.
    Enquist, Magnus
    et al.
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution. Brooklyn College, USA; Graduate Center of the City University of New York, USA.
    The power of associative learning and the ontogeny of optimal behaviour2016In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 3, no 11, article id 160734Article in journal (Refereed)
    Abstract [en]

    Behaving efficiently (optimally or near-optimally) is central to animals' adaptation to their environment. Much evolutionary biology assumes, implicitly or explicitly, that optimal behavioural strategies are genetically inherited, yet the behaviour of many animals depends crucially on learning. The question of how learning contributes to optimal behaviour is largely open. Here we propose an associative learning model that can learn optimal behaviour in a wide variety of ecologically relevant circumstances. The model learns through chaining, a term introduced by Skinner to indicate learning of behaviour sequences by linking together shorter sequences or single behaviours. Our model formalizes the concept of conditioned reinforcement (the learning process that underlies chaining) and is closely related to optimization algorithms from machine learning. Our analysis dispels the common belief that associative learning is too limited to produce ‘intelligent’ behaviour such as tool use, social learning, self-control or expectations of the future. Furthermore, the model readily accounts for both instinctual and learned aspects of behaviour, clarifying how genetic evolution and individual learning complement each other, and bridging a long-standing divide between ethology and psychology. We conclude that associative learning, supported by genetic predispositions and including the oft-neglected phenomenon of conditioned reinforcement, may suffice to explain the ontogeny of optimal behaviour in most, if not all, non-human animals. Our results establish associative learning as a more powerful optimizing mechanism than acknowledged by current opinion.

  • 8.
    Fransson, Thord
    et al.
    Naturhistoriska Riksmuseet.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Johansson, Patrik
    Sveriges geologiska undersökningar.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Valllin, Adrian
    Stockholm University, Faculty of Science, Department of Zoology.
    Magnetic cues trigger extensive refuelling2001In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 414, p. 35-36Article in journal (Refereed)
  • 9.
    Ghirlanda, Stefano
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Brooklyn College, USA.
    Enquist, Magnus
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Coevolution of intelligence, behavioral repertoire, and lifespan2014In: Theoretical Population Biology, ISSN 0040-5809, E-ISSN 1096-0325, Vol. 91, p. 44-49Article in journal (Refereed)
    Abstract [en]

    Across many taxa, intriguing positive correlations exist between intelligence (measured by proxy as encephalization), behavioral repertoire size, and lifespan. Here we argue, through a simple theoretical model, that such correlations arise from selection pressures for efficient learning of behavior sequences. We define intelligence operationally as the ability to disregard unrewarding behavior sequences, without trying them out, in the search for rewarding sequences. We show that increasing a species' behavioral repertoire increases the number of rewarding behavior sequences that can be performed, but also the time required to learn such sequences. This trade-off results in an optimal repertoire size that decreases rapidly with increasing sequence length. Behavioral repertoire size can be increased by increasing intelligence or lengthening the lifespan, giving rise to the observed correlations between these traits.

  • 10.
    Ghirlanda, Stefano
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Brooklyn College, USA.
    Enquist, Magnus
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Corrigendum to "Coevolution of intelligence, behavioral repertoire, and lifespan" [Theoret. Popul. Biol. 91 (2014) 44–49]2014In: Theoretical Population Biology, ISSN 0040-5809, E-ISSN 1096-0325, Vol. 97, p. 57-57Article in journal (Other academic)
  • 11.
    Ghirlanda, Stefano
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Brooklyn College, USA; CUNY Graduate Center, USA.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    ‘Aesop's fable’ experiments demonstrate trial-and-error learning in birds, but no causal understanding2017In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 123, p. 239-247Article in journal (Refereed)
    Abstract [en]

    Experiments inspired by Aesop's fable The crow and the pitcher have been suggested to show that some birds (rooks, Corvus frugilegus, New Caledonian crows, Corvus moneduloides, and Eurasian jays, Garrulus glandarius) understand cause–effect relationships pertaining to water displacement. For example, the birds may prefer to drop stones in water rather than in sand in order to retrieve a floating food morsel, suggesting that they understand that only the level of water can be so raised. Here we re-evaluate the evidence for causal understanding in all published experiments (23 928 choices by 36 individuals). We first show that commonly employed statistical methods cannot disentangle the birds' initial performance on a task (which is taken as an indicator of causal understanding) from trial-and-error learning that may occur during the course of the experiment. We overcome this shortcoming with a new statistical analysis that quantifies initial performance and learning effects separately. We present robust evidence of trial-and-error learning in many tasks, and of an initial preference in a few. We also show that both seeming demonstrations of causal understanding and of lack of it can be understood based on established properties of instrumental learning. We conclude that Aesop's fable experiments have not yet produced evidence of causal understanding, and we suggest how the experimental designs can be modified to yield better tests of causal cognition.

  • 12.
    Ghirlanda, Stefano
    et al.
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution. Brooklyn College, USA; Graduate Center of the City University of New York, USA.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Enquist, Magnus
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Memory for stimulus sequences: a divide between humans and other animals?2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 6, article id 161011Article in journal (Refereed)
    Abstract [en]

    Humans stand out among animals for their unique capacities in domains such as language, culture and imitation, yet it has been difficult to identify cognitive elements that are specifically human. Most research has focused on how information is processed after it is acquired, e.g. in problem solving or 'insight' tasks, but we may also look for species differences in the initial acquisition and coding of information. Here, we show that non-human species have only a limited capacity to discriminate ordered sequences of stimuli. Collating data from 108 experiments on stimulus sequence discrimination (1540 data points from 14 bird and mammal species), we demonstrate pervasive and systematic errors, such as confusing a red-green sequence of lights with green-red and green-green sequences. These errors can persist after thousands of learning trials in tasks that humans learn to near perfection within tens of trials. To elucidate the causes of such poor performance, we formulate and test a mathematical model of non-human sequence discrimination, assuming that animals represent sequences as unstructured collections of memory traces. This representation carries only approximate information about stimulus duration, recency, order and frequency, yet our model predicts non-human performance with a 5.9% mean absolute error across 68 datasets. Because human-level cognition requires more accurate encoding of sequential information than afforded by memory traces, we conclude that improved coding of sequential information is a key cognitive element that may set humans apart from other animals.

  • 13.
    Henshaw, Ian
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Fransson, Thord
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for Cultural Evolution.
    Vallin, Adrian
    Stockholm University, Faculty of Science, Department of Zoology.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology.
    Food intake and fuel deposition in a migratory bird is affected by multiple as well as single-step changes in the magnetic field2008In: Journal of Experimental Biology, ISSN 0022-0949, E-ISSN 1477-9145, Vol. 211, p. 649-653Article in journal (Refereed)
    Abstract [en]

    Recent studies have shown that migratory thrush nightingales (Luscinia luscinia) experimentally treated with multiple changes of the magnetic field simulating a journey to their target stopover area in northern Egypt, increased fuel deposition as expected in preparation to cross the Sahara desert. To investigate the significance of food intake on the body mass changes observed, in the work described here we analysed food intake of the nightingales under study in those earlier experiments. Furthermore, to study whether a single change in the magnetic field directly to northern Egypt is sufficient to provide information for fuelling decisions, we performed a new experiment, exposing thrush nightingales trapped in Sweden, directly to a magnetic field of northern Egypt. Our results show that an experimentally induced magnetic field of northern Egypt, close to the barrier crossing, triggers the same response in fuel deposition as experiments with multiple changes of the magnetic field simulating a migratory journey from Sweden to Egypt, suggesting that migratory birds do not require successive changes in field parameters to incorporate magnetic information into their migratory program. Furthermore, irrespective of experimental set up (single or multiple changes of the magnetic field parameters) increase in food intake seems to be the major reason for the observed increase in fuelling rate compared with control birds, suggesting that geomagnetic information might trigger hormonal changes in migratory birds enabling appropriate fuelling behaviour during migration.

  • 14.
    Kaby, Ulrika
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    What limits predator detection in blue tits (Parus caeruleus): posture, task or orientation2003In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 54, no 6, p. 534-538Article in journal (Refereed)
    Abstract [en]

    To detect threats and reduce predation risk prey animals need to be alert. Early predator detection and rapid anti-predatory action increase the likelihood of survival. We investigated how foraging affects predator detection and time to take-off in blue tits (Parus caeruleus) by subjecting them to a simulated raptor attack. To investigate the impact of body posture we compared birds feeding head-down with birds feeding head-up, but could not find any effect of posture on either time to detection or time to take-off. To investigate the impact of orientation we compared birds having their side towards the attacking predator with birds having their back towards it. Predator detection, but not time to take-off, was delayed when the back was oriented towards the predator. We also investigated the impact of foraging task by comparing birds that were either not foraging, foraging on chopped mealworms, or foraging on whole ones. Foraging on chopped mealworms did not delay detection compared to nonforaging showing that foraging does not always restrict vigilance. However, detection was delayed more than 150% when the birds were foraging on whole, live mealworms, which apparently demanded much attention and handling skill. Time to take-off was affected by foraging task in the same way as detection was. We show that when studying foraging and vigilance one must include the difficulty of the foraging task and prey orientation.

  • 15.
    Kullberg, Cecilia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Kaby, Ulrika
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Impaired flight ability prior to egg laying: A cost of being a capital breeder2005In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 19, no 1, p. 98-101Article in journal (Refereed)
    Abstract [en]
    • 1To investigate flight ability in captive Zebra Finches during reproduction we compared change in escape take-off ability and wing load of reproducing females with their mates and non-reproducing females when attacked by a model raptor.
    • 2Initially females had 18% higher wing load than males. Non-reproducing females and females that had started egg-laying flew slower than males. Reproducing females reduced wing load during egg-laying and flew faster when the clutch was completed. Non-breeding females remained on high wing load and flow slower than breeding females that had completed their clutch.
    • 3The increase in flight speed of breeding females was explained by a reduction in wing load during egg-laying.
    • 4Zebra Finches use accumulated reserves to produce eggs and pay a cost in terms of reduced flight ability, but then regain flight performance when the clutch is laid, probably demonstrating a predation cost of capital breeding in birds.
  • 16.
    Kullberg, Cecilia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    An experimental study of predator recognition in great tit fledglings2002In: Ethology, ISSN 0179-1613, E-ISSN 1439-0310, Vol. 108, no 5, p. 429-441Article in journal (Refereed)
    Abstract [en]

    Studies of naturally predator-naïve adult birds (finches on predator-free islands) and birds experimentally hand reared in isolation from predators indicate that birds can recognise predators innately; that is, birds show anti-predator behaviour without former experience of predators. To reduce predation risk efficiently during the vulnerable fledgling period, we would predict an innate response to be fully developed when the chicks leave the nest. However, 30-day-old naïve great tit fledglings (Parus major) did not respond differently to a model of a perched predator than to a similarly sized model of a non-predator. Although chicks showed distress responses such as warning calls and freezing behaviour, they did not differentiate between the stimuli. In contrast, wild-caught first-year birds (4 mo old) and adults responded differentially to the two stimuli. Lack of recognition of a perched predator might be one explanation for the high mortality rate found in newly fledged great tits. Our results imply that parental care is not only important for food provisioning, but also to reduce predation risk during the time when fledglings are most vulnerable

  • 17.
    Kullberg, Cecilia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Fransson, Thord
    Naturhistoriska Riksmuseet.
    Vallin, Adrian
    Stockholm University, Faculty of Science, Department of Zoology.
    Magnetic cues and time of season affect fuel deposition in migratory thrush nightingales (Luscinia luscinia)2003In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 270, no 1513, p. 373-378Article in journal (Refereed)
    Abstract [en]

    Bird migration requires high energy expenditure, and long–distance migrants accumulate fat for use as fuel during stopovers throughout their journey. Recent studies have shown that long–distance migratory birds, besides accumulating fat for use as fuel, also show adaptive phenotypic flexibility in several organs during migration. The migratory routes of many songbirds include stretches of sea and desert where fuelling is not possible. Large fuel loads increase flight costs and predation risk, therefore extensive fuelling should occur only immediately prior to crossing inhospitable zones. However, despite their crucial importance for the survival of migratory birds, both strategic refuelling decisions and variation in phenotypic flexibility during migration are not well understood. First–year thrush nightingales (Luscinia luscinia) caught in the early phase of the onset of autumn migration in southeast Sweden and exposed to a magnetic treatment simulating a migratory flight to northern Egypt increased more in fuel load than control birds. By contrast, birds trapped during the late phase of the onset of autumn migration accumulated a high fuel load irrespective of magnetic treatment. Furthermore, early birds increased less in flight–muscle size than birds trapped later in autumn. We suggest that the relative importance of endogenous and environmental factors in individual birds is affected by the time of season and by geographical area. When approaching a barrier, environmental cues may act irrespective of the endogenous time programme.

  • 18.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Adaptive body regulation in the life history of birds2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [sv]

    Birds have been flying on this Earth for around 150 million years and in response to fluctuating environments birds have evolved flexible body regulation. This thesis has investigated costs and adaptations in bird body regulation in different life history stages, namely moult and migration. Moult, the shedding and replacement of feathers, did surprisingly not impair tree sparrows Passer montanus flight ability indicating that they compensate physiologically for the wing area reductions experienced during moult. This compensatory aptness was then shown as tree sparrows developed a larger flight muscle relative to body mass when wing area was reduced during natural moult. This pattern was established in an experiment where birds reduced their body mass concurrently with enlarging flight muscle size in response to wing area reductions. In addition, group size affects birds' risk perception and tree sparrows were also found to regulate their bodies according to how large group they were living in, in accordance with theory on predation risk in birds. These experiments show potentially adaptive and novel organ flexibility patterns in birds. Compensatory regulation was then tested in the field, but tree sparrows in the wild did not exhibit the same patterns as birds in the experiments. Physiological constraints and group size-effects probably explain these results. Migration is also an important life history stage and birds en route must also regulate their bodies to environmental demands. Sea and desert often interrupt migration and large energy stores are needed to cross such barriers. Yet, large energy stores incur costs, and that large fuel loads impair take-off ability was demonstrated. Hence, birds do often only accumulate modest amount of fuel. This illustrates an important problem for migrating birds, specifically, how can naïve birds know a priori that they are about to cross a barrier and consequently must fuel up extensively. Thrush nightingales Luscinia luscinia are trans-Saharan migrants and were therefore held in Sweden and subjected to experiments where only the magnetic field was changed. They undertook a simulated magnetic journey from Sweden to northern Egypt and were then allowed to refuel for five days prior to the “desertcrossing”. Compared to control birds, thrush nightingales were found to accumulate larger fat deposits when subjected to the magnetic treatment, showing, for the first time, that birds can incorporate geomagnetic cues in their fuelling decisions. This rapid flexibility and the ability to incorporate external cues in refuelling probably reflect the paramount importance and long history of flight in birds.

  • 19.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Bivarg Philanthus triangulum2017In: Fauna och flora : populär tidskrift för biologi, ISSN 0014-8903, Vol. 112, no 3, p. 42-42Article in journal (Other (popular science, discussion, etc.))
  • 20.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Book review of Sturkie's Avian Physiology, 2000 (ed) G.C. Whittow2001In: Ornis Svecica, ISSN 1102-6812, Vol. 11, no 4, p. 268-270Article, book review (Other (popular science, discussion, etc.))
  • 21.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Book review of Wings over Falsterbo, 2004, (ed) L. Karlsson2005In: Ibis, ISSN 0019-1019, E-ISSN 1474-919X, Vol. 147, p. 428-Article, book review (Other (popular science, discussion, etc.))
  • 22.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Escape flight in moulting tree sparrows (Passer montanus)2001In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 15, no 1, p. 29-35Article in journal (Refereed)
    Abstract [en]
    • 1 Impaired predator evasion in birds as a cost in different life-history periods has received increasing attention in the last decade. Evasive abilities in birds have been found to be detrimentally affected by migratory fuel load, reproduction and moult. These results suggest that during these periods of their lives birds suffer from increased predation risk due to impaired evasive abilities.
    • 2 Theoretically, moult should have a detrimental effect on flight, and empirical work on starlings has shown impaired escape ability due to moult. However, a recent theoretical investigation found a surprisingly small effect of moult on flight in birds.
    • 3 In this study, 31 Tree Sparrows, a sedentary species with a slow moult, were used to investigate the effect of natural and manipulated moult on escape ability. No effect was found due to natural moult, however, when experimentally increasing moult gap size a strong negative effect was found.
    • 4  With support from empirical and theoretical work, this is the first study to suggest that slow moult may not increase predation risk due to impaired evasive abilities. Compensatory physiological adaptations probably cause this result and may be very important during moult.
    • 5 Predation risk is probably an important factor in the evolution of moult patterns and moult strategies.
  • 23.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Inget stöd för att kråkfåglar kan resonera2017In: Sans, ISSN 2000-9690, no 3, p. 10-15Article in journal (Other (popular science, discussion, etc.))
  • 24.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Mytomspunna vridvingar - om en dröm som gick i uppfyllelse2014In: Fauna och flora : populär tidskrift för biologi, ISSN 0014-8903, Vol. 109, no 2, p. 2-6Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Ett tips på Facebook vägledde zoologen Johan Lind till hans livs entomologiska dröm, nämligen att få se och fotografera vridvingar. Dessa sällan observerade insekter har en fascinerande livscykel, som delvis pågår inuti sälgsandbin eller andra insekter.

  • 25.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Nobelkommittén gjorde inte hemläxan inför medicinpriset2014In: Svenska dagbladet, ISSN 1101-2412, no 22 novemberArticle in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Har Nobelkommittén missat ett sekel av beteendeforskning när de motiverar årets pris med uttalanden om råttors höga intelligens? Den frågar ställer Johan Lind, docent i etologi vid Stockholms universitet.

  • 26.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Näbbars ursprung2017In: Vår fågelvärld med Fågelvännen, ISSN 2002-2743, no 4, p. 20-24Article in journal (Other (popular science, discussion, etc.))
  • 27.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Quercus: Ekens mångfald2010 (ed. 1. uppl.)Book (Other (popular science, discussion, etc.))
  • 28.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Quercus: The Oak and Diversity2010Book (Other (popular science, discussion, etc.))
  • 29.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Reduced take-off ability in robins due to migratory fuel load1999In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 46, no 1, p. 65-70Article in journal (Refereed)
    Abstract [en]

    Recent studies have shown that large fuel loads in small birds impair flying ability. This is the first study to show how migratory fuel load affects flying ability, such as velocity and height gained at take-off in a predator escape situation, in a medium-distance migrant, and whether they adjust their take-off according to predator attack angle. First-year robins (Erithacus rubecula) were subjected to simulated attacks from a model merlin (Falco columbarius), and take-off velocity and angle were analysed. Robins with a wing load of 0.19 g cm−2 took off at a 39% lower angle than robins with a wing load of 0.13 g cm−2, while velocity remained unaffected. The robins did not adjust their angle of ascent in accordance with the predator's angle of attack. Since many predators rely on surprise attacks, a difference in flight ability due to varying fuel loads found in migrating robins can be important for birds' chances of survival when actually attacked.

  • 30.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    Skräntärna i skyddad verkstad2015In: Fauna och flora : populär tidskrift för biologi, ISSN 0014-8903, Vol. 110, no 3, p. 12-14Article in journal (Other (popular science, discussion, etc.))
  • 31.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    To eat or not to eat, that is the question: Being too heavy may make a bird vulnerable to predators2000In: Interpretive Birding Bulletin, Vol. 1, p. 12-14Article in journal (Other (popular science, discussion, etc.))
  • 32.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Tree sparrow, Passer montanus, freezing in the presence of a sparrowhawk, Accipiter nisus2002In: Ornis Svecica, Vol. 12, p. 214-215Article in journal (Refereed)
  • 33.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Tropikhavens okända djur2017In: Fauna och flora : populär tidskrift för biologi, ISSN 0014-8903, Vol. 112, no 2, p. 32-36Article in journal (Other (popular science, discussion, etc.))
  • 34.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Varför bry sig om sin vikt?2002In: Fåglar i Stockholmstrakten, Vol. 31, p. 28-33Article in journal (Other (popular science, discussion, etc.))
  • 35.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Vigilance and models of behaviour2010In: Encyclopedia of Animal Behaviour, volume 3 / [ed] Breed M.D., Moore J., Oxford: Academic press , 2010, p. 506-510Chapter in book (Other academic)
  • 36.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for Cultural Evolution.
    What can associative learning do for planning?2018In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 5, no 11, article id 180778Article in journal (Refereed)
    Abstract [en]

    There is a new associative learning paradox. The power of associative learning for producing flexible behaviour in non-human animals is downplayed or ignored by researchers in animal cognition, whereas artificial intelligence research shows that associative learning models can beat humans in chess. One phenomenon in which associative learning often is ruled out as an explanation for animal behaviour is flexible planning. However, planning studies have been criticized and questions have been raised regarding both methodological validity and interpretations of results. Due to the power of associative learning and the uncertainty of what causes planning behaviour in non-human animals, I explored what associative learning can do for planning. A previously published sequence learning model which combines Pavlovian and instrumental conditioning was used to simulate two planning studies, namely Mulcahy & Call 2006 'Apes save tools for future use.' Science 312, 1038-1040 and Kabadayi & Osvath 2017 'Ravens parallel great apes in flexible planning for tool-use and bartering. 'Science 357, 202-204. Simulations show that behaviour matching current definitions of flexible planning can emerge through associative learning. Through conditioned reinforcement, the learning model gives rise to planning behaviour by learning that a behaviour towards a current stimulus will produce high value food at a later stage; it can make decisions about future states not within current sensory scope. The simulations tracked key patterns both between and within studies. It is concluded that one cannot rule out that these studies of flexible planning in apes and corvids can be completely accounted for by associative learning. Future empirical studies of flexible planning in non-human animals can benefit from theoretical developments within artificial intelligence and animal learning.

  • 37.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    What determines the probability of surviving predator attacks in bird migration?: The relative importance of vigilance and fuel load2004In: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 231, no 2, p. 223-227Article in journal (Refereed)
    Abstract [en]

    Migrating birds must accumulate fuel during their journeys and this fuel load should incur an increased risk of predation. Migratory fuelling should increase individual mass-dependent predation risk for two reasons. First, acquisition costs are connected to the increased time a bird must spend foraging to accumulate the fuel loads and the reduced predator detection that accompanies foraging. Second, birds with large fuel loads have been shown to suffer from impaired predator evasion which makes them more vulnerable when actually attacked. Here, I investigate the relative importance of these two aspects of mass-dependent predation risk and I have used published data and a hypothetical situation for a foraging bird to investigate how much migratory fuelling in terms of escape performance and natural variation in predator detection contribute to individual risk during foraging. Results suggest that for birds foraging close to protective cover the negative impact of fuel load on flight performance is very small, whereas variation in time to predator detection is of great importance for a bird's survival. However, the importance of flight performance for predation risk increases as the distance to cover increases. Hence, variation in predator detection (and vigilance) probably influences individual survival much more than migratory fuel load and consequently, to understand risk management during migration studies that focus on vigilance and predator detection during fuelling are much needed

  • 38.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Cresswell, Will
    University of St Andrews.
    Anti-predation behaviour during bird migration: The benefit of studying multiple behavioural dimensions2006In: Journal of Ornithology = Journal fur Ornithologie, ISSN 0021-8375, E-ISSN 1439-0361, Vol. 147, p. 310-316Article in journal (Refereed)
  • 39.
    Lind, Johan
    et al.
    University of St Andrews.
    Cresswell, Will
    University of St Andrews.
    Determining the fitness consequences of anti-predation behavior2005In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 16, p. 945-956Article in journal (Refereed)
    Abstract [en]

    Any animal whose form or behavior facilitates the avoidance of predators or escape when attacked by predators will have a greater probability of surviving to breed and therefore greater probability of producing offspring (i.e., fitness). Although in theory the fitness consequences of any antipredation behavior can simply be measured by the resultant probability of survival or death, determining the functional significance of antipredation behavior presents a surprising problem. In this review we draw attention to the problem that fitness consequences of antipredation behaviors cannot be determined without considering the potential for reduction of predation risk, or increased reproductive output, through other compensatory behaviors than the behaviors under study. We believe we have reached the limits of what we can ever understand about the ecological effects of antipredation behavior from empirical studies that simply correlate a single behavior with an apparent fitness consequence. Future empirical studies must involve many behaviors to consider the range of potential compensation to predation risk. This is because antipredation behaviors are a composite of many behaviors that an animal can adjust to accomplish its ends. We show that observed variation in antipredation behavior does not have to reflect fitness and we demonstrate that few studies can draw unambiguous conclusions about the fitness consequences of antipredation behavior. Lastly, we provide suggestions of how future research should best be targeted so that, even in the absence of death rates or changes in reproductive output, reasonable inferences of the fitness consequences of antipredation behaviors can be made.

  • 40.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    More synthetic work is needed2009In: Adaptive Behavior, ISSN 1059-7123, E-ISSN 1741-2633, Vol. 17, no 4, p. 329-330Article in journal (Refereed)
  • 41.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Brooklyn College, USA.
    Animal memory: A review of delayed matching-to-sample data2015In: Behaviour Analysis Letters, ISSN 0376-6357, Vol. 117, p. 52-58Article, review/survey (Refereed)
    Abstract [en]

    We performed a meta-analysis of over 90 data sets from delayed matching-to-sample (DMTS) studies with 25 species (birds, mammals, and bees). In DMTS, a sample stimulus is first presented and then removed. After a delay, two (or more) comparison stimuli are presented, and the subject is rewarded for choosing the one matching the sample. We used data on performance vs. delay length to estimate two parameters informative of working memory abilities: the maximum performance possible with no delay (comparison stimuli presented as soon as the sample is removed), and the rate of performance decay as the delay is lengthened (related to memory span). We conclude that there is little evidence that zero-delay performance varies between these species. There is evidence that pigeons do not perform as well as mammals at longer delay intervals. Pigeons, however, are the only extensively studied bird, and we cannot exclude that other birds may be able to bridge as long a delay as mammals. Extensive training may improve memory, although the data are open to other interpretations. Overall, DMTS studies suggest memory spans ranging from a few seconds to several minutes. We suggest that observations of animals exhibiting much longer memory spans (days to months) can be explained in terms of specialized memory systems that deal with specific, biologically significant information, such as food caches. Events that do not trigger these systems, on the other hand, appear to be remembered for only a short time. This article is part of a Special Issue entitled: In Honor of jeriy Hogan.

  • 42.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Enqvist, Magnus
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Insight Learning and Shaping.2012In: Encyclopedia of the Sciences of Learning, Springer Publishing Company, 2012, p. 1574-1577Chapter in book (Refereed)
  • 43.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    Insight learning or shaping?2009In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 106, no 28, p. E76-Article in journal (Refereed)
  • 44.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies. Stockholm University, Faculty of Science, Department of Zoology.
    Ghirlanda, Stefano
    Enquist, Magnus
    Stockholm University, Faculty of Science, Department of Zoology.
    Social learning through associative processes: a computational theory2019In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 3, article id 181777Article in journal (Refereed)
    Abstract [en]

    Social transmission of information is a key phenomenon in the evolution of behaviour and in the establishment of traditions and culture. The diversity of social learning phenomena has engendered a diverse terminology and numerous ideas about underlying learning mechanisms, at the same time that some researchers have called for a unitary analysis of social learning in terms of associative processes. Leveraging previous attempts and a recent computational formulation of associative learning, we analyse the following learning scenarios in some generality: learning responses to social stimuli, including learning to imitate; learning responses to non-social stimuli; learning sequences of actions; learning to avoid danger. We conceptualize social learning as situations in which stimuli that arise from other individuals have an important role in learning. This role is supported by genetic predispositions that either cause responses to social stimuli or enable social stimuli to reinforce specific responses. Simulations were performed using a new learning simulator program. The simulator is publicly available and can be used for further theoretical investigations and to guide empirical research of learning and behaviour. Our explorations show that, when guided by genetic predispositions, associative processes can give rise to a wide variety of social learning phenomena, such as stimulus and local enhancement, contextual imitation and simple production imitation, observational conditioning, and social and response facilitation. In addition, we clarify how associative mechanisms can result in transfer of information and behaviour from experienced to naive individuals.

  • 45.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Gustin, Marco
    LIPU.
    Sorace, Alberto
    Instituto Superiore di Sanità.
    Compensatory bodily changes during moult in tree sparrows, Passer montanus, in Italy2004In: Ornis Fennica, ISSN 0030-5685, Vol. 81, no 2, p. 75-83Article in journal (Refereed)
    Abstract [en]

    To cope with fluctuating environments animals have evolved reversible phenotypic flexibility.Some birds demonstrate this phenomenon by changing mass and flight muscle according to changes in wing loading. During moult, birds suffer from reduced wing area because feathers are shed and replaced, resulting in a wing loading increase. Moult is rather well studied in birds, but the perspective of phenotypic flexibility has been neglected. Therefore,we tested predictions generated from experimental studies by collecting information about bodymass, flightmuscle size and fat stores from an Italian population of Tree Sparrows (Passer montanus) to investigate if they compensate physiologically for the wing area reductions they suffer from during moult. Our results did not corroborate predictions based on experimental studies; that is, the Tree Sparrows did not reduce body mass and increase in flight muscle size as a response to wing area reductions during midmoult. Instead, body mass increased throughout moult, flight muscle size did not change, and fat stores decreased asmoult progressed. To further investigate compensatory changes, we analysed bodily differences in midmoult between birds differing in moult gap size. Again, contrary to predictions from experimental studies, birds having larger moult gaps were found to have higher body mass. These birds were also found to keep the ratio between flight muscle size and body mass constant over the day whereas birds with small moult gaps reduced this ratio over the day. Birds with large moult gaps ere also found to store less fat than birdswith small gaps. Physiological constraints may help to explain these results and underlying reasons for the observed variation in bodily regulation in birds are discussed.

  • 46.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Hollén, Linda
    Stockholm University, Faculty of Science, Department of Zoology.
    Smedberg, Erik
    Stockholm University, Faculty of Science, Department of Zoology.
    Svensson, Ulrika
    Stockholm University, Faculty of Science, Department of Zoology.
    Vallin, Adrian
    Stockholm University, Faculty of Science, Department of Zoology.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Detection distance influencing escape behaviour in two parids (Parus major and P. caeruleus)2003In: Journal of Avian Biology, ISSN 0908-8857, E-ISSN 1600-048X, Vol. 34, no 3, p. 233-236Article in journal (Refereed)
    Abstract [en]

    When birds are attacked by aerial predators they should benefit by adjusting their escape to the prevailing attack situation. One important factor likely to affect escape decisions of prey, to our knowledge not previously studied, is the distance at which the attacking predator is detected. We investigated if great tits Parus major and blue tits P. caeruleus alter their escape behaviour to two different detection distances (2.3 m and 1m) by simulating surprise attacks using a predator model. Both species used the information about detection distance when escaping by increasing the escape angle at the shorter detection distance. In addition, blue tits adjusted to the shorter detection distance by dodging sideways more frequently. Great tits escaped initially steeper and faster than blue tits, whereas blue tits increased escape angle and speed more than great tits along the measured distance after taking wing

  • 47.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Body-building and concurrent mass loss: flight adaptations in tree sparrows2001In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 268, no 1479, p. 1915-1919Article in journal (Refereed)
    Abstract [en]

    Environmental changes are responsible for the evolution of flexible physiology and the extent of phenotypic plasticity in the regulation of birds' organ size has not been appreciated until recently. Rapid reversible physiological changes during different life–history stages are virtually only known from long–distance migrants, and few studies have focused on less extreme aspects of organ flexibility. During moult, birds suffer from increased wing loading due to wing–area reductions, which may impair flight ability. A previous study found that tree sparrows' escape flight (Passer montanus) is unaffected during moult, suggesting compensatory aptness. We used non–invasive techniques to study physiological adaptations to increased wing loading in tree sparrows. As wing area was reduced during natural moult the ratio of pectoral–muscle size to body mass increased. When moult was completed this ratio decreased. We show experimentally a novel, strategic, organ–flexibility pattern. Unlike the general pattern, where body mass is positively coupled to pectoral–muscle size, tree sparrows responded within 7 days to reductions in wing area by reducing body mass concurrently with an increase in pectoral–muscle size. This rapid flexibility in a non–migratory species probably reflects the paramount importance and long history of flight in birds.

  • 48.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Ethology. Stockholm University, Faculty of Science, Department of Zoology.
    Jakobsson, Sven
    Stockholm University. Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Kullberg, Cecilia
    Stockholm University. Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Impaired predator evasion in the life-history of birds: behavioral and physiological adaptations to reduced flight ability.2010In: Current Ornithology, Vol. 17, p. 1-30Article in journal (Refereed)
  • 49.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Jöngren, Fredrik
    Stockholm University, Faculty of Science, Department of Zoology.
    Nilsson, Jenny
    Stockholm University, Faculty of Science, Department of Zoology.
    Schönberg Alm, David
    Stockholm University, Faculty of Science, Department of Zoology.
    Strandmark, Alma
    Stockholm University, Faculty of Science, Department of Zoology.
    Information, predation risk and foraging decisions during mobbing in great tits, Parus major2005In: Ornis Fennica, ISSN 0030-5685, Vol. 82, p. 89-96Article in journal (Refereed)
    Abstract [en]

    Tomaximise survival during foraging animalsmust decide when and for how long foraging should be interrupted in order to avoid predators. Previous experiments have shown that birds that hear other individuals’alarm calls resume feeding later than those that see a flying predator.However, the responses of prey animals to enemies are highly context-dependent. We therefore investigated how birds respond to a threat less serious than a flying hawk depending on different amount of information about the predator. We used Great Tits dyadswhere one individual saw a perchedmodel predator (sender), whereas the other individual could only hear the conspecific’s mobbing calls (receiver). The sender responded appropriately as shown by comparing their responses to how they responded to a control.We also found that while senders were exposed to the predator, receivers became more wary and reduced their activity level. However, despite the receivers having less information about predation risk they still did not prolong the time they took to resume foraging. Hence, once the mobbing ceased (and consequently the transmission of information about the predator stopped) therewas no effect of only having second-hand information. This also shows that receiver’s rely upon the sender’smobbing calls suggesting that mobbing calls may act as honest signals of the prevailing predation risk. In conclusion, our results support the view that responses of prey to predators are highly context-dependent and that birds’ anti-predator responses are a result of an interaction between the amount of information and the level of the threat.

  • 50.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Kaby, Ulrika
    Stockholm University, Faculty of Science, Department of Zoology.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Split-second escape decisions in blue tits (Parus caeruleus)2002In: Die Naturwissenschaften, ISSN 0028-1042, E-ISSN 1432-1904, Vol. 89, no 9, p. 420-423Article in journal (Refereed)
    Abstract [en]

    Bird mortality is heavily affected by birds of prey. Under attack, take-off is crucial for survival and even minor mistakes in initial escape response can have devastating consequences. Birds may respond differently depending on the character of the predator's attack and these split-second decisions were studied using a model merlin (Falco columbarius) that attacked feeding blue tits (Parus caeruleus) from two different attack angles in two different speeds. When attacked from a low attack angle they took off more steeply than when attacked from a high angle. This is the first study to show that escape behaviour also depends on predator attack speed. The blue tits responded to a high-speed attack by dodging sideways more often than when attacked at a low speed. Escape speed was not significantly affected by the different treatments. Although they have only a split-second before escaping an attack, blue tits do adjust their escape strategy to the prevailing attack conditions.

12 1 - 50 of 65
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf