Recognition of Familiar Visual Landmarks in Homing Pigeons

1993 ◽  
Vol 46 (3) ◽  
pp. 371-375 ◽  
Author(s):  
V. A. Braithwaite ◽  
T. C. Guilford
Keyword(s):  
Release Site ◽  
Columba Livia ◽  
Relative Importance ◽  
Visual Landmarks ◽  
Homing Pigeons ◽  
Homing Behaviour ◽  
Similar Improvement ◽  
Current Location

It is now well established that homing pigeons (Columba livia) use a variety of mechanisms and cues to help them find their way home. It is far more difficult to determine the relative importance attached to such mechanisms and cues by pigeons during homing. As a step towards this quantitative stage in our understanding of homing behaviour we consider if cues contribute significantly to homing speed. In particular we attempt to assess the role of visual landmarks. Using pigeons released from familiar release sites, we demonstrate that birds home faster if they can view their surroundings from inside a Perspex box for 5 minutes prior to being released, compared to birds denied this view. Pigeons released from unfamiliar sites, however, do not show a similar improvement. We suggest that seeing familiar visual landmarks before release allows pigeons to become more certain of their current location with respect to home. Simply viewing the release site is not sufficient to produce a faster homing speed; the pigeons must be able to recognize that the release site is familiar.

scholarly journals Group decisions and individual differences: route fidelity predicts flight leadership in homing pigeons ( Columba livia )

2010 ◽  
Vol 7 (1) ◽  
pp. 63-66 ◽  
Author(s):  
Robin Freeman ◽  
Richard Mann ◽  
Tim Guilford ◽  
Dora Biro
Keyword(s):  
Individual Differences ◽  
Individual Variation ◽  
Columba Livia ◽  
Homing Pigeon ◽  
Scientific Interest ◽  
Homing Pigeons ◽  
Collective Decisions ◽  
The Subject ◽  
Leadership Decisions

How social-living animals make collective decisions is currently the subject of intense scientific interest, with increasing focus on the role of individual variation within the group. Previously, we demonstrated that during paired flight in homing pigeons, a fully transitive leadership hierarchy emerges as birds are forced to choose between their own and their partner's habitual routes. This stable hierarchy suggests a role for individual differences mediating leadership decisions within homing pigeon pairs. What these differences are, however, has remained elusive. Using novel quantitative techniques to analyse habitual route structure, we show here that leadership can be predicted from prior route-following fidelity. Birds that are more faithful to their own route when homing alone are more likely to emerge as leaders when homing socially. We discuss how this fidelity may relate to the leadership phenomenon, and propose that leadership may emerge from the interplay between individual route confidence and the dynamics of paired flight.

scholarly journals Tracking clock-shifted homing pigeons from familiar release sites

2000 ◽  
Vol 203 (2) ◽  
pp. 207-212 ◽  
Author(s):  
F. Bonadona ◽  
R. Holland ◽  
L. Dall'Antonia ◽  
T. Guilford ◽  
S. Benvenuti
Keyword(s):  
Large Scale ◽  
Release Site ◽  
Homing Pigeon ◽  
Homing Pigeons ◽  
Pigeon Navigation ◽  
Wrong Direction ◽  
Terrain Features ◽  
Clock Shift

Clock-shifted homing pigeons were tracked from familiar sites 17.1 km and 23.5 km from the home loft in Pisa, Italy, using an on-board route recorder. At the first release site, north of home, the majority of clock-shifted birds had relatively straight tracks comparable with those of control birds. At the second release site, south of home, the clock-shifted birds deflected in the direction predicted for the degree of clock shift, with many birds travelling some distance in the wrong direction before correcting their course. The possible role of large-scale terrain features in homing pigeon navigation is discussed.

Population Control (Review Article)

1961 ◽  
Vol 1 (3) ◽  
pp. 89-98
Author(s):  
Karol J. Krotki
Keyword(s):  
Population Control ◽  
Review Article ◽  
Small Enterprise ◽  
Opportunity Costs ◽  
Relative Importance ◽  
Factual Information ◽  
Undue Influence ◽  
Clear Cut ◽  
Economic Considerations

Discussions about the role of small enterprise in economic development tend to remain inconclusive partly because of the difficulty of assessing the relative importance of economic and non-economic objectives and partly because of the dearth of factual information on which to base an economic calculus. It is probably true, moreover, that, because of a lack of general agreement as to the economic case for or against small enterprise, non-economic considerations, including some merely romantic attitudes toward smallness and bigness, tend to exert an undue influence on public policies. There may, of course, be no clear-cut economic case. And noneconomic considerations should and will inevitably weigh significantly in policy decisions. If, however, some of the economic questions could be settled by more and better knowledge, these decisions could more accurately reflect the opportunity costs of pursuing non-economic objectives.

scholarly journals Role of propagule pressure in colonization success: disentangling the relative importance of demographic, genetic and habitat effects

2013 ◽  
Vol 26 (8) ◽  
pp. 1691-1699 ◽  
Author(s):  
R. A. Hufbauer ◽  
A. Rutschmann ◽  
B. Serrate ◽  
H. Vermeil de Conchard ◽  
B. Facon
Keyword(s):  
Propagule Pressure ◽  
Relative Importance ◽  
Colonization Success

scholarly journals The Arctic as a “Strategic” and “Important” Chinese Foreign Policy Interest: Exploring the Role of Labels and Hierarchies in China’s Arctic Discourses

2021 ◽  
pp. 186810262110186
Author(s):  
Patrik Andersson
Keyword(s):  
Foreign Policy ◽  
International Relations ◽  
Political Discourse ◽  
Chinese Foreign Policy ◽  
The Arctic ◽  
Relative Importance ◽  
Precise Understanding ◽  
New Frontier ◽  
Political Priority

Research confirms that China is becoming more engaged in the Arctic. However, international relations scholarship often extrapolates from relatively few instances of activity to wide-ranging claims about Chinese priorities. Fortunately, Chinese political discourse is organised by labels that allow us to study how the Arctic is classified and ranked along China’s other foreign policy priorities. This article analyses two such classifications – “important maritime interest” and “strategic new frontier,” exploring how they have come about, what they mean, and how they add political priority to the Arctic. It argues that hierarchies are constructed in two ways: by adding gradients and by including/excluding categories of priority. It views categories as performative: they not only convey information about character and relative importance of interests but are also used for achieving different objectives. By focusing on foreign policy classifications, the article contributes to a more nuanced and precise understanding of China’s Arctic interests.

Possible cues driving context-specific adaptation of optocollic reflex in pigeons (Columba livia)

2012 ◽  
Vol 107 (2) ◽  
pp. 704-717 ◽  
Author(s):  
Henri Gioanni ◽  
Pierre-Paul Vidal
Keyword(s):  
Columba Livia ◽  
Motor Command ◽  
Slow Phase ◽  
Gaze Stabilization ◽  
Specific Adaptation ◽  
Body Vibration ◽  
Fast Phase ◽  
Context Specific ◽  
Context Cues

Context-specific adaptation (Shelhamer M, Clendaniel R. Neurosci Lett 332: 200–204, 2002) explains that reflexive responses can be maintained with different “calibrations” for different situations (contexts). Which context cues are crucial and how they combine to evoke context-specific adaptation is not fully understood. Gaze stabilization in birds is a nice model with which to tackle that question. Previous data showed that when pigeons ( Columba livia) were hung in a harness and subjected to a frontal airstream provoking a flying posture (“flying condition”), the working range of the optokinetic head response [optocollic reflex (OCR)] extended toward higher velocities compared with the “resting condition.” The present study was aimed at identifying which context cues are instrumental in recalibrating the OCR. We investigated that question by using vibrating stimuli delivered during the OCR provoked by rotating the visual surroundings at different velocities. The OCR gain increase and the boost of the fast phase velocity observed during the “flying condition” were mimicked by body vibration. On the other hand, the newly emerged relationship between the fast-phase and slow-phase velocities in the “flying condition” was mimicked by head vibration. Spinal cord lesion at the lumbosacral level decreased the effects of body vibration, whereas lesions of the lumbosacral apparatus had no effect. Our data suggest a major role of muscular proprioception in the context-specific adaptation of the stabilizing behavior, while the vestibular system could contribute to the context-specific adaptation of the orienting behavior. Participation of an efferent copy of the motor command driving the flight cannot be excluded.

Study of the role of Chlamydia, Mycoplasma, Ureaplasma and other microaerophilic and aerobic bacteria in uterine infections of mares with reproductive disorders

2003 ◽  
Vol 51 (1) ◽  
pp. 45-52 ◽  
Author(s):  
László Szeredi ◽  
M. Tenk ◽  
I. Schiller ◽  
Keyword(s):  
Pathogenic Bacteria ◽  
Anaerobic Bacteria ◽  
Aerobic Bacteria ◽  
Relative Importance ◽  
Reproductive Disorders ◽  
Taylorella Equigenitalis

In six healthy mares and 24 mares showing reproductive disorders swab samples were taken from the fossa clitoridis to isolate Taylorella equigenitalis, and from the uterus to isolate mycoplasmas, ureaplasmas and other aerobic bacteria. Swab samples were also taken from the uterus for Chlamydiaantigen ELISA and ChlamydiaPCR studies. The uterus of 27 mares was examined cytologically, and biopsy samples were taken from the endometrium for histological examinations and for immunohistochemical examinations aimed at the detection of chlamydiae. T. equigenitalis, mycoplasmas, ureaplasmas and chlamydiae could not be detected from any of the mares examined. Aerobic facultative pathogenic bacteria were isolated from mares with endometritis in four cases. In 18 out of 22 mares with endometritis (82%) no infective agents could be demonstrated. Further studies are needed to elucidate the relative importance of non-infectious causes of endometritis and of anaerobic bacteria often detectable in the uterus in the aetiology of the reproductive disorders observed.

scholarly journals Do patients value a hospital’s innovativeness reputation? A multi-method approach to assess the relative importance of innovativeness reputation in patients’ hospital choice

2017 ◽  
Vol 31 (3) ◽  
pp. 138-153 ◽  
Author(s):  
Sebastian Gurtner ◽  
Nadine Hietschold ◽  
María Vaquero Martín
Keyword(s):  
Value Added ◽  
Patient Choice ◽  
Relative Importance ◽  
Hospital Choice ◽  
Patient Decision ◽  
Technical Innovations ◽  
Multi Method Approach ◽  
Method Approach

Innovations in health care are costly and risky, but they also provide the opportunity for hospitals to increase quality of care, to distinguish themselves from competitors and to attract patients. While numerous hospitals strive to increase their innovativeness by adopting a costly innovation leader strategy, the question of whether this actually influences the patient’s choice remains unanswered. To understand the role of innovativeness from the patient perspective, this study conceptualizes the construct of innovativeness reputation of hospitals and determines its relevance in patients’ hospital choice decisions. In the pretest, we identified six dimensions of innovativeness reputation such as progressive work procedures and value added services. We then used three different quantitative multi-criteria decision-making methods to evaluate the relative importance of innovativeness reputation in patient choice. We collected data from 355 former German patients who had undergone elective non-emergency surgery. Overall, innovativeness reputation accounts for 11.6%–16.8% of the patient decision. Innovativeness reputation has a moderate influence on hospital choice and should be taken into account by managers. Since technical innovations are costly, hospitals should use other means to enhance their innovative image. Strategies such as emphasizing value added services can enable hospitals to increase their innovativeness reputation efficiently.

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