world record pigeon flight home was set on 15th June 1932.
The bird disappeared after being released in Arras, France, and it was
not for 24 days afterwards before it arrived back at its original loft in Saigon,
Vietnam, after flying 10,640 kilometres (in a straight line). This is the longest
known distance and the actual world's record and was reported in the paper "La
Prensa" of Barcelona.
do pigeons find their way? How can they orient themselves for such long distances?
What is the secret of the pigeon's navigation? Most probably there is not "just
an answer" but a combination of several factors. Scientists and pigeon’
fanciers of the entire world are still working on this amazing fact that makes
pigeons so fascinating and such useful birds.
is a very interesting article about pigeon navigation written by Verner P. Bingman
(Racing Pigeon Pictorial, September 1993) that explains the actual knowledge
on this matter. I hope you find it as interesting as I did.
the well-documented finding that birds can rely on the earth's magnetic field
for compass orientation (Wiltschko, 1983), it is not surprising that hypotheses
citing a role for geomagnetism in the functioning of the navigational map of
pigeons have also appeared. Interestingly, the possible importance of geomagnetism
in permitting a bird to determine its location in space was already suggested
long before it was established as compass cue (Yeagley, 1947). The supporting
evidence indicating a role for geomagnetism for the navigational map includes:
- Correlation between variations in the initial orientation of pigeons following
release with naturally occurring fluctuations in geomagnetic field.
- Impaired initial orientation of racing pigeons when released within naturally
occurring magnetic anomalies.
- Disrupted initial orientation following experimentally induced magnetic disturbances.
results of these studies link magnetic stimuli with pigeon homing performance.
The effects are plausibly attributed to affect a map mechanism rather than compass
orientation, as the experiments are performed under sunny conditions when the
birds are known to rely on the sun for compass orientation. However, the possibility
of an interaction between magnetic stimuli and sun compass orientation, which
manifests itself under conditions of magnetic disturbance, cannot be entirely
excluded as an explanation for the reported results. Indeed until an experiment
is performed whereby manipulating the ambient magnetic field exposed to a bird
results in predictable shifts in orientation that are interpretable in the context
of a map, uncertainties will remain regarding its importance, and the question
of a geomagnetic role in the pigeon navigation map will remain open.
have discussed olfactory and geomagnetic cues as independent sources of potential
map information. It remains conceivable, however, that they may work in some
collective fashion to permit a pigeon to locate its position in space. For example,
if the map does take the form of a bico-ordinate gradient system, olfactory
stimuli may characterise one axis, and magnetic cues could characterise the
other. Although this is as yet a highly speculative notion, Wallraff, Papi,
Ioalé & Benvenuti, (1986) have reported that olfactory and magnetic stimuli
may interact at some level of the homing process. Racing pigeons exposed to
oscillating magnetic fields coupled with deprivation of their sense of smell
prior to release fail to show the usual deviation away from the homeward direction
characteristic of the magnetic field treatment alone (Benvenuti et al, 1982).
Regional and individual differences
the possibility of multiple sensory mechanisms associated with the pigeon navigational
map, it seems important to consider to what extent regional differences may
account for these findings. The currently available evidence indicates that
wherever it has been extensively studied, olfaction plays a critical role in
the proper functioning of the pigeon navigational map. Nonetheless olfactory
treatments have been reported to be less affective in altering navigational
performance in other locations in Germany and the Unites States.
this time it is important to consider how and why the importance of smells for
navigation may vary regionally. Indeed, potential regionally differences could
be based on differences in atmospheric dynamics that may render curried odours
more or less reliable as sources of navigational information.
situation with geomagnetism is somewhat more difficult, insofar as it remains
unclear to what extent it may be involved in the navigational map. Nevertheless
findings indicate that pigeons from different lofts are differentially affected
at the same magnetic anomaly.
looking at baseline individual behaviour performance, pigeons in different regions
are not equally good at returning home following release from unfamiliar locations.
For example, birds generally perform better in Italy than in Germany. Raising
Italian birds in Germany and German birds in Italy has indicated that baseline
differences are, at least in part, environmentally based, possibly reflecting
differences in the way environmental cues are employed in the formation of a
navigational map. The available evidence indicates that such may be the case,
supporting Keeton's (1974) belief that environmental factors may determine the
extent to close this section by emphasising that current available evidence
implicates smell as the primary source of navigational map information, with
the demonstration of alternative sources awaiting further empirical support.
far we have focused on true navigation, or that mechanism that permits a pigeon
to approximate its position in space relative to home from places it has never
been before. However, when a racing pigeon is in an area where it has been before,
either when returning to the loft from an unknown site or when released in a
familiar area, it then has available an additional source of potential navigational
information in the form of familiar landmarks, which may or may not be visual.
its intuitive appeal, the extent to which landmarks are used by racing pigeons
in generating goal-orientated responses has been one of the most empirically
elusive issues in avian navigational research. Nonetheless there are strong
indications that racing pigeons do use landmarks for locating their position
with respect to home when they are in a familiar area but outside the range
of direct sensory contact with their loft. Racing pigeons approaching the familiar
area around the loft have been recorded to make appropriate course corrections.
Pigeons wearing frosted lenses that affect their vision are successful in orienting
homeward from a distant, unfamiliar release site, but appear impaired in returning
to their loft once they get to within three to six miles. Finally, racing pigeons
which are not permitted free-flight experience around their loft prior to their
first experimental release, orient homeward from a distant location, indicating
an ability to perform true navigation, but are impaired in locating their loft
once within its vicinity. This suggests that flight experience is important
for adequate local navigation near the loft, presumably by permitting familiarisation
with local landmarks.
source of evidence indicating that racing pigeons attend to landmarks for navigation
comes from experiments where racing birds are initially impaired at orienting
homeward from a distant, unfamiliar release site. However, upon repeated exposure
to the, now familiar, release site, the birds become better at orienting homeward
following the same experimental procedure that originally rendered them impaired.
Familiarity with an area enables pigeons to compensate for disruptions in their
navigational map, and it seems reasonable to suppose that this familiarity effect
is based on the use of landmarks that they had been exposed to. This familiarity
effect has been observed under diverse conditions:
- Olfactory-deprived pigeons which generally fail to orient homeward from unfamiliar
locations, do orient homeward when released from locations they had been previously.
- When released within a magnetic anomaly, racing pigeons are often disoriented.
However, there is considerable improvement in homeward orientation on subsequent
releases from the same anomaly.
- Racing pigeons that are clock-shifted, a procedure that result in predictable
change in an animal's monitoring of the sun for sun compass orientation, typically
display a deviation in orientation with respect to home when released from either
familiar or unfamiliar locations. However, they compensate at least partially
for that deviation when released under clock-shift conditions a second time
from the same location.
results suggest that racing pigeons do indeed use landmarks for navigation.
However, it should be emphasised that they are likely used under normal conditions
primarily to locate the loft once in its vicinity, that vicinity depending on
the previous experience of a pigeon (perhaps up to fifteen miles to the loft).
The possible use of landmarks from distant, unfamiliar locations should be viewed
as an auxiliary mechanism to be employed when use of their navigational map
is disrupted or has previously been associated with incorrect orientation.
Landmark Navigation - Theoretical
that racing pigeons use landmarks for navigation, it becomes important to consider
how they may be used. In the following discussion, we consider landmarks within
the context of local navigation near the loft, but the ideas can be generalised
to landmarks use at distant familiar locations as well. Two important questions
emerge: (a) What is the nature
of the spatial or location purposes (e.g., "my location is north of the
loft") or are they also employed in guiding orientation response (e.g.,
"therefore I should fly to this side of the water tower").
respect to the first question, two possibilities occur. First, pigeons may rely
on landmarks in the form of a mosaic map, whereby a pigeon learns the fixed
directional relationships of landmarks or landmark complexes with respect to
the loft and/or other landmarks. For example, a pigeon relying on such a system,
acquired through experience and coded in terms of compass directions, could
learn that the water tower lies north of the loft, or perhaps that the water
tower lies north-east of the rubbish dump/truck garage complex, with pigeons
associating a single compass directions, or a limited set of compass directions,
with respect to any given landmark. In this model each landmark is used as an
independent source of information. Use of a mosaic landmark map has been hypothesised
to occur at familiar release sites where pigeons are able to orient homeward
by having presumably associated a site-specific homeward orientation response
with a single set of local landmarks during previous visits.
possibility is that landmarks are not used independently as signposts, but collectively
in the form of an integrated map. Such a system is characterised by the use
of at least a subset of the same group of landmarks from effectively any location
where sensory contact with them would be possible. Such a mapping system is
advantageous because the same pool of landmarks could be used over an infinite
number of locations within an area of familiarity. The superiority of such a
cognitive mapping system compared to the mosaic system is effective only from
specific locations, for example, the water tower, where a pigeon would have
had the opportunity to associate a limited set of directional responses with
respect to goal areas. The cognitive mapping system confers considerably more
flexibility in getting home from anywhere within a known area.
series of articles has been adapted from Spatial Navigation in Birds, Chapter
14, Neurobiology of Comparative Cognition". (R. Kesner & D. Olton,
eds. 1990, Erlbaum, Hillside, N.J.)
Pictures © Gary Hardy (1990)