Papers by Michael Shalter
Animal Behaviour, Nov 1, 1978
Seven pairs of breeding pied flycatchers (Ficedula hypoleuca) were repeatedly presented a stuffed... more Seven pairs of breeding pied flycatchers (Ficedula hypoleuca) were repeatedly presented a stuffed owl from a specific location until their mobbing response had waned. Subsequent change in the location of the 'predator' evoked renewed responsiveness from the birds, as ...
Nature, Jun 1, 1972
Imprinting SIR,-The earliest reported historical references to imprinting frequently cited in rev... more Imprinting SIR,-The earliest reported historical references to imprinting frequently cited in reviews of the subject 1-3 are the systematic observations of Spalding'. Spalding observed that "chickens as soon as they are able to walk will follow any moving object. And, when guided by sight alone, they seem to have no more disposition to follow a hen than to follow a duck, or a human being". The following response and the formation of attachments of young nidifugous birds were noted, however, more than 350 years earlier by Sir Thomas More. In his classic treatise Utopia, first published in Latin in 1516, appeared the following account of a practice in Utopia: "They breed vast numbers of chickens by a most ex:traordinary method. Instead of leaving the hens to sit on the eggs, they hatch out dozens at a time applying a steady heat to them-with the result that when the chicks come out of the shells, they regard the poultryman as their mother, and follow him everywhere! "•\_ One wonders whether More's allusion to imprinting was derived from then-existing knowledge applied perhaps in some foreign land, or was the product of his own observations and imagination. In either case it appears doubtful that remarks presented in a treatise on a utopian state would be addressed to knowledge common to Britain at the time. It would be difficult to assess the heuristic value of More's statements on imprinting for subsequent thinkers, but one is reminded of Chaucer's words (lines 24-25, The Parlement of Foules): "And out of olde books, in good feith cometh al this new science that men Jere". Yours faithfully,
Nature, May 1, 1972
THE inheritance of some simple behavioural traits, according to Scott and Fuller, can be explaine... more THE inheritance of some simple behavioural traits, according to Scott and Fuller, can be explained on the basis of one or two genes1. Hirsch has suggested that it is impossible to study the genetics of a behaviour and that only the genetics of a population can be analysed, on the grounds that the relation between behavioural variation and relevant genetic
Zeitschrift für Tierpsychologie, Apr 26, 2010
and SummaryIn the laboratory setting, anti‐predator behavior tends to habituate so fast that its ... more and SummaryIn the laboratory setting, anti‐predator behavior tends to habituate so fast that its value for the prey's survival appears questionable. We propose that excessive habituation is caused by the artificially stereotyped presentation of stimulus objects, which is commonly used for the sake of precise stimulus control. To test this hypothesis, we habituated young angel fish (Pterophyllum eimecki) to a moving shadow on one side of the test chamber, and then presented the moving shadow on the opposite side of the chamber. Since the responsiveness was restored in the vast majority of these trials, our hypothesis stays upheld. This result is discussed in the context of an earlier hypothesis, namely that from the prey's vantage point relative rareness is an important feature of predators in the natural setting (SCHLEIDT 1961).ZusammenfassungNach einer früher vertretenen Hypothese ist vom Standpunkt des Beutetieres die relative Seltenheit im natürlichen Lebensraum ein wichtiges Merkmal von Raubfeinden (SCHLEIDT 1961).In Laborversuchen gewöhnen sich Beutetiere im allgemeinen schneller an Freßfeinde als für das Überleben tragbar erscheint. Wir nehmen an, daß diese schnelle Gewöhnung ein Kunstprodukt der gleichförmigen Darbietung des Reizobjektes ist. Um das zu prüfen, gewöhnten wir junge Segelflosser (Pterophyllum eimecki) zunächst an einen sich bewegenden Schatten an einer Wand der Versuchskammer und boten dann den gleichen sich bewegenden Schatten an der gegenüberliegenden Wand. Durch diese Ortsveränderung wurde in der überwiegenden Mehrzahl der Versuche das Feindmeidungsverhalten wiederhergestellt.
Ibis, Apr 3, 2008
hunt their prey by sight, whilst others probe at a very rapid rate presumably finding their prey ... more hunt their prey by sight, whilst others probe at a very rapid rate presumably finding their prey by touch. The feeding efficiency of the birds hunting by sight is adversely affected by surface disturbance and the withdrawal of their prey; such disturbance is less likely to affect those hunting by touch. Accordingly, the sight-hunting species were found to be dispersed in loosely-knit flocks (in which mutual interference would be reduced) whereas the touch-hunting species formed very compact flocks. In the sight-hunters feeding efficiency favours solitary feeding and, in interaction with the predation pressure to congregate, the resultant dispersion is a loose flock. Feeding efficiency in those hunting by touch is not inconsistent with gregariousness and compact flocks are the result. T o summarise, the feeding dispersion of a species is the result of an interaction of selection pressures for minimising predation risk and maximising feeding efficiency. If these pressures conflict, each will be compromised somewhat to produce a dispersion system characterised by a counterbalance of advantages. The observed diversity of feeding dispersion is the product of two sources of variation: the gross qualitative variation due to feeding efficiency, promoting either gregariousness or solitariness, and the quantitative variation in the pressure to flock in order to minimise the risk from predation. A final point: Murton (1971 a, Zoc. cit.) considers that the antf;predator functio?; of flocking are " secondary adaptations ". I believe that to speak of" primary and " secondary adaptations in the present context can only encourage simplistic explanation. Such terms imply, for two selection pressures, a difference in their effect on individual fitness, a difference in their generality of application or a temporal ordering. The first implication can only be discussed at the species level. The second, as I have tried to show, is an oversimplification without any explanatory value. The third implication-temporal ordering-can also be dispelled. Flocks do not emerge as a consequence of one selection pressure only then to be influenced by another (except perhaps in cases of sudden emigration to a new habitat). Any pressures which influence dispersion will do so interactively so as to gradually change the dispersion system.
Ibis, Apr 3, 2008
SummaryTen Barn Owls were tested in a sound‐room with recordings of various alarm calls and noise... more SummaryTen Barn Owls were tested in a sound‐room with recordings of various alarm calls and noise. The owls readily responded with head movements to the majority of stimuli and correctly oriented to their source. The seeet alarm call and the ‘warning’ call elicited the least responses, but they were properly localized by all owls which did respond. This suggests that rather than non‐localizability accounting for the fewer observed responses to the seeet and ‘warning’ calls, there is either something else in the quality of those sounds, or in the manner in which they are processed by the bird, which does not elicit responses to the degree that transient sounds with broad frequencies do. Selection in these predators for non‐responsiveness is suggested as a counter‐strategy to minimize futile energy expenditure in attacking, or otherwise responding to an alerted prey.An additional hypothesis, consistent with Darwin's antithesis principle, is proposed whereby intraspecific and interspecific selection, rather than predator selection for non‐localizability, has led to the evolution of seeet and mobbing calls.
Zeitschrift für Tierpsychologie, Apr 26, 2010
and Summary I. 7 vocalizations emitted in the predator context are defined in terms of their func... more and Summary I. 7 vocalizations emitted in the predator context are defined in terms of their function. The physical and physiological constraints on the evolution of the physical structure of alarm calls with respect to detectability and localizability are discussed. Detection of various calls depends on signal amplitude, environmental attenuation, signal-to-noise ratio, discrimination of the receiver against background noise, and absolute auditory sensitivity of the receiver. The combined effect of these factors is discussed for an exemplary predator-prey system, in which the hearing of both, predator and prey is known. Localizability of an alarm call is determined by its frequency, bandwidth, and possibly its amplitude relative to the auditory threshold of the receiver. Crude differentiation between localizable and non-localizable signals is not possible, and localizability of particular sounds varies between species. In some cases the question of detectability may render the problem of localizability unimportant. Besides detectability and localizability, other factors such as the acoustic background formed by the alarm calls of sympatric species and by the species' own repertoire of calls are discussed. II. Requisite conditions and available evidence for the evolution of alarm calls through individual selection and kin selection are described. Five types of alarm calls are discussed individually: 1The occurrence of mobbing calls indicates that a major function of these calls is predator deterrence (“move on”), although the calls also alert other prey and promote cultural transmission of the predator's characteristics. 2Alarm calls associated with evasive actions of the prey cause the predator to give up the hunt or diminish its hunting success by warning other prey, which only in some cases are closely related to the caller. 3Distress calls of a seized prey either attract other prey which then mob the predator, or attract other predators, which presumably attack the first predator. In both cases the chances to escape are enhanced because the predator's attention is diverted. 4Defence calls are used to threaten a predator. These calls often mimic sounds of other predators. 5Distraction calls may enhance the effect of distraction display. Although the different functions of various alarm calls are treated individually, certain of the calls may have more than one function and may be employed in nonpredator contexts as well.
Journal of Ornithology, Oct 1, 1978
Kurze Mitteilungen Studies of mobbing behaviour abound*).-BARASH (1976) stated that his study of ... more Kurze Mitteilungen Studies of mobbing behaviour abound*).-BARASH (1976) stated that his study of crows constitutes "the first potentially replicabIe quantitative data of mobbing behavior in free-living birds". Such a claim of priority is clearly unwarranted in view of the large number of quantitative studies of this behaviour that have been published in the last decades. In a review on enemy recognition in birds, CURIO (1963) gare an account of studies with free-living birds involving many aspects of the functlonal organizatlon and adaptive significance of mobbing. Those studies had been quantified, e.g. by scoring calI repetition rate, approach distance toward the predator, the number of birds responding and other measures. Since that review, mobbing behaviour has been subsequently investigated mainly to elucidate questions about the releaslng stlmuli, its functional organisation,
Zeitschrift für Tierpsychologie, Apr 26, 2010
A surprisingly high proportion (42%) of breeding pied flycatchers failed to mob a stuffed pygmy o... more A surprisingly high proportion (42%) of breeding pied flycatchers failed to mob a stuffed pygmy owl placed near the nests. To determine whether the range of effective stimulus objects eliciting mobbing could be extended in these "non-mobbers", a live owl, resembling the ineffective dummy in nearly all static owl traits, was briefly exposed. It evoked strong mobbing from all birds, as did the stuffed specimen on a subsequent presentation. The role of experience with live predators and the effect of labile properties of the latter on the mobbing response are discussed.
Behaviour, 1977
Two naive wolf pups (Canis lupus) were presented a variety of sound stimuli, including standardiz... more Two naive wolf pups (Canis lupus) were presented a variety of sound stimuli, including standardized recordings of natural and synthetic adult howls. The greatest and most consistent vocal response was elicited by the "real" howls. The nature of the response depended in part upon the i) type of stimulus, 2) number of stimulus presentations, 3) associated manipulations of context, and 4) individual differences in vocal responsiveness. Neither specific ongoing behaviors nor general activity levels of the pups appears to have mediated their vocal behavior. Differential responses demonstrated their ability to distinguish between recorded howls of adult wolves. Manipulation of the context, through presentation of either a human observer, live dog, or live mice increased the pups' vocalizations to the recordings. The results are discussed in terms of both extrinsic and intrinsic determinants of an animal's response to communication signals.
Journal of Comparative and Physiological Psychology, May 1, 1975
Domestic and jungle fowl were presented either an acoustic stimulus (warning call) or a visual st... more Domestic and jungle fowl were presented either an acoustic stimulus (warning call) or a visual stimulus (black ball) from a particular location until response waning was achieved. Subsequent change of the location from which either stimulus was presented evoked renewed responsiveness as measured by elicited vocalizations and avoidance behavior. The stimulus specificity conferred by ever changing spatial contexts may explain in partthe relative lack of response decrement to recurring predators and alarm communication in natural situations.
The Condor, 1977
The Carolina Wren (Thryothorus ludovicicreate a uniform visual background. It was provided anus) ... more The Carolina Wren (Thryothorus ludovicicreate a uniform visual background. It was provided anus) has a social system that is much more with a one-way observation window. characteristic of tropical than temperate zone The hawk was trained to fly across the room to an species. Males and females form permanent exposed perch. It flew from a perch concealed from pair bonds (Bent 1948, Thomas 1953, and the wrens directly over the caged wrens to a perch in view of the wrens. The hawk was tethered-to a pers. observ. of a color-banded population monofilament line on a nullv which standardized its over 4 years) and pairs defend a territory flight path. When in flight,-the hawk passed 1.7 m throughout the year. above the cage to a perch 2.5 m from the center of Probably due to this social system, Carolina the wren cage. Wren sounds elicited were tape-recorded via a Wrens use all of their vocal signals throughout microphone in the testing room. Concurrently from the year (Morton, in press). Here we present an adjacent room, we observed wren and hawk bedata derived from field observations and lab-havior and tape-recorded our observations. oratory experiments on one of this wren' s vo-The sounds were analyzed on a Kay Elemetrics cal signals, which we term the chirt. Carolina Sonograph; amplitude and temporal data were analyzed with a B and K graphic level recorder. Wren chirts are structurally variable and are delivered in temporally variable ways. We FIELD STUDY hope to explain here how this call varies and A population varying from 8 to 10 pairs in deciduous how its variation is adaptive within the Caro-forest surrounding one author' s residence was colorlina Wren' s social system. Since chirt calls banded. Nearly daily monitoring of behavioral events depart from the commonly held view that within the population was made by Morton from April 1972 to September 1975. Vocalizations were most bird sounds are rather discrete (Marler tape-recorded together with observations of contextual 1967, Smith 1968, 1969), a discussion of them events (Morton, in press). Naturally occurring chirts may shed new light on sources of selection were included in this study and are discussed here.
Zeitschrift für Tierpsychologie, Apr 26, 2010
Goshawks and pygmy owls responded to recordings of passerine alarm calls by correctly orienting t... more Goshawks and pygmy owls responded to recordings of passerine alarm calls by correctly orienting to their source. The seeet. or aerial predator alarm call which is generally assumed to be non-localizable, while it elicited fewer responses than did mobbing calls, was never- ...
Journal of Ornithology, 1978
Kurze Mitteilungen Studies of mobbing behaviour abound*).-BARASH (1976) stated that his study of ... more Kurze Mitteilungen Studies of mobbing behaviour abound*).-BARASH (1976) stated that his study of crows constitutes "the first potentially replicabIe quantitative data of mobbing behavior in free-living birds". Such a claim of priority is clearly unwarranted in view of the large number of quantitative studies of this behaviour that have been published in the last decades. In a review on enemy recognition in birds, CURIO (1963) gare an account of studies with free-living birds involving many aspects of the functlonal organizatlon and adaptive significance of mobbing. Those studies had been quantified, e.g. by scoring calI repetition rate, approach distance toward the predator, the number of birds responding and other measures. Since that review, mobbing behaviour has been subsequently investigated mainly to elucidate questions about the releaslng stlmuli, its functional organisation,
Nature, 1972
Imprinting SIR,-The earliest reported historical references to imprinting frequently cited in rev... more Imprinting SIR,-The earliest reported historical references to imprinting frequently cited in reviews of the subject 1-3 are the systematic observations of Spalding'. Spalding observed that "chickens as soon as they are able to walk will follow any moving object. And, when guided by sight alone, they seem to have no more disposition to follow a hen than to follow a duck, or a human being". The following response and the formation of attachments of young nidifugous birds were noted, however, more than 350 years earlier by Sir Thomas More. In his classic treatise Utopia, first published in Latin in 1516, appeared the following account of a practice in Utopia: "They breed vast numbers of chickens by a most ex:traordinary method. Instead of leaving the hens to sit on the eggs, they hatch out dozens at a time applying a steady heat to them-with the result that when the chicks come out of the shells, they regard the poultryman as their mother, and follow him everywhere! "•\_ One wonders whether More's allusion to imprinting was derived from then-existing knowledge applied perhaps in some foreign land, or was the product of his own observations and imagination. In either case it appears doubtful that remarks presented in a treatise on a utopian state would be addressed to knowledge common to Britain at the time. It would be difficult to assess the heuristic value of More's statements on imprinting for subsequent thinkers, but one is reminded of Chaucer's words (lines 24-25, The Parlement of Foules): "And out of olde books, in good feith cometh al this new science that men Jere". Yours faithfully,
Zeitschrift für Tierpsychologie, 2010
Ibis, 2008
hunt their prey by sight, whilst others probe at a very rapid rate presumably finding their prey ... more hunt their prey by sight, whilst others probe at a very rapid rate presumably finding their prey by touch. The feeding efficiency of the birds hunting by sight is adversely affected by surface disturbance and the withdrawal of their prey; such disturbance is less likely to affect those hunting by touch. Accordingly, the sight-hunting species were found to be dispersed in loosely-knit flocks (in which mutual interference would be reduced) whereas the touch-hunting species formed very compact flocks. In the sight-hunters feeding efficiency favours solitary feeding and, in interaction with the predation pressure to congregate, the resultant dispersion is a loose flock. Feeding efficiency in those hunting by touch is not inconsistent with gregariousness and compact flocks are the result. T o summarise, the feeding dispersion of a species is the result of an interaction of selection pressures for minimising predation risk and maximising feeding efficiency. If these pressures conflict, each will be compromised somewhat to produce a dispersion system characterised by a counterbalance of advantages. The observed diversity of feeding dispersion is the product of two sources of variation: the gross qualitative variation due to feeding efficiency, promoting either gregariousness or solitariness, and the quantitative variation in the pressure to flock in order to minimise the risk from predation. A final point: Murton (1971 a, Zoc. cit.) considers that the antf;predator functio?; of flocking are " secondary adaptations ". I believe that to speak of" primary and " secondary adaptations in the present context can only encourage simplistic explanation. Such terms imply, for two selection pressures, a difference in their effect on individual fitness, a difference in their generality of application or a temporal ordering. The first implication can only be discussed at the species level. The second, as I have tried to show, is an oversimplification without any explanatory value. The third implication-temporal ordering-can also be dispelled. Flocks do not emerge as a consequence of one selection pressure only then to be influenced by another (except perhaps in cases of sudden emigration to a new habitat). Any pressures which influence dispersion will do so interactively so as to gradually change the dispersion system.
Zusammenfassung Hunde und Wölfe gehören zur breiten Palette von Raubtieren und Aasfressern, deren... more Zusammenfassung Hunde und Wölfe gehören zur breiten Palette von Raubtieren und Aasfressern, deren Evolution vor etwa 10 Millionen Jahren zusammen mit der von herdenlebenden Huftieren begann. Während der Eiszeit war der Grauwolf Canis lupus das vorherrschende Raubtier Europas. Indem er mit den Wanderungen der Huftierherden Schritt halten konnte, wurde er zum ersten „Hirten “unter den Säugetieren.
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Papers by Michael Shalter