Roswitha Wiltschko

Effect of Outward Journey in an Altered Magnetic Field on the Orientation of Young Homing Pigeons

To test whether magnetic directional information gained during the outward journey is incorporated in determining the home direction after displacement, young homing pigeons were transported to the release site in an artificially altered magnetic field. Controls were transported in a separate vehicle; a third group of birds was transported together with the controls, but after arriving at the release site, they were placed in the altered field for a period equal to the duration of the journey.

Cognitive maps and navigation in homing pigeons

It is an obvious necessity for all animals that have some kind of “home” to be able to orient within their home range, i.e. between their home, suitable food sources, water etc.. This allows fast and efficient movements which will minimize the time and energy expenditure and help to reduce the periods in which the animals are exposed to predation. Hence it is not surprising that orientational abilities have been found in many species of vertebrates, social insects and numerous other invertebrates (see Schmidt-Koenig 1975). But the most outstanding performances have been reported from birds. Migrating birds fly to their distant wintering areas and return to last year’s breeding territory often after completing a journey of several thousand kilometers. Homing pigeons are able to return to their home after passive displacement of several hundreds of kilometers into completely unknown territory.

Mechanisms of Orientation and Navigation in Migratory Birds

Every year in autumn, myriads of migrating birds leave their breeding areas and start the long flight towards their wintering areas, which often are thousands of kilometres away. Migration means several weeks or even months of travelling, which may include crossing ecological barrieres, like mountains, seas and deserts. The birds have to face and solve a number of physiological and ecological problems, like meeting the energy requirements of the extended flight and finding suitable refuelling areas along the route etc. A major problem, however, concerns orientation and navigation: while adult migrants are already familiar with the route and a winter quarter that allowed their survival during the previous year, the young birds migrating for the first time have to reach their population-specific wintering area that is still unknown to them.

Pigeon homing and magnetic fields: a response to Luschi et al. (1996)

This paper comments on an article ‘Pigeon homing: evidence against reliance on magnetic information picked up en route at release sites’ by P. Luschi, C. del Seppia, E. Crosio and F. Papi, which appeared in this journal. It is pointed out that the particular effects which these authors show to be stress–induced artefacts are restricted to their specific strain of homing pigeons. The same effects could not be observed in pigeons from two other lofts—a difference in response that was shown to have a genetic base. In view of this, conclusions drawn from the results of Luschi et al. must be restricted to their own findings; they cannot be generalized to the other findings which indicate the use of magnetic outward journey information in young homing pigeons.

Pigeon Homing: The Effect of Temporary Anosmia on Orientation Behavior

Carrier pigeons, Columba livia, re Leased at unfamiliar sites, do not depart randomly, but fly in directions that are normally not far from the homeward course. This indicates that the birds are aware in what direction their ‘home’ lies, and leads to the question: how do the birds know? Avian orientation has been the subject of intensive research during the last few decades, and some parts of this question can already be answered. Navigation is commonly described as a two-step process: In the first step, the map step, the birds determine their home direction as a compass course, and in the second step, they locate this course with the help of a compass and fly in the respective direction. The second step, the compass step, is rather well understood: Pigeons preferentially use a time-compensating sun compass which is, under overcast, backed up by a magnetic compass. The nature of the map step, however, is still largely unknown.