Tracking homing pigeons by GPS

Thesis

The present thesis utilises recently developed miniature GPS loggers to track homing pigeons (Columba livia) navigating within their familiar area. This technology allows tracks of extremely high spatial and temporal resolution to be recorded providing a unique opportunity for novel data analysis.

The thesis focuses on the development of pigeons' tracks as they become increasingly experienced with a homing task. Birds' routes became increasingly stereotyped over time, were individually distinctive, and remained substantially longer than the beeline. This was demonstrated at short distances (~5 km) and at 25 km from home. Pigeons seem to use a similar strategy when homing from the longer distance site as at shorter distances, although the distance beyond which this strategy may become inefficient remains to be elucidated.

It seems likely that the cues involved in performing detailed stereotyped routes are familiar visual landmarks, as birds' routes remain stable over varying wind conditions and are resistant to a magnetic disruption treatment. Furthermore, birds released at novel sites perpendicularly displaced along their homeward routes are attracted back to and rejoin their established routes. This demonstrates that the route cues used can be detected and accurately assessed from distances of several kilometres, again suggesting that these route cues are visual.

Birds released at sites they had flown over as part of their stereotyped routes appear unable to recognise their routes until airborne which, along with previous experiments, suggests that certain limitations apply to visual recognition, which could have profound effects on the way visual landmarks are remembered and subsequently recognised. This, in addition to the similarity between the stereotyped routes performed by pigeons and the foraging routes performed by some insects (ants, bees and wasps) allows novel parallels to be drawn between pigeon and insect navigation.

The ability of birds to detect and accurately assess route cues from distances of several kilometres suggests that pigeons may be able to perform detailed stereotyped routes via visual attraction between successive landmarks without reference to a compass system. This hypothesis is tested in the final experimental chapter which incorporates artificial manipulation of the birds' sense of compass direction through a clock-shift treatment. The results show that while some birds are able to perform their stereotyped routes without the aid of the sun compass, in others the sun-compass may have a role to play even after they have become extremely familiar with a local homing task.

The combined results demonstrate an extremely important role for visual landmarks in familiar area navigation, and provide evidence as to how familiar visual landmarks are remembered, recognised, and encoded by homing pigeons.

Authors: Meade, J; Meade, Jessica

• Publication date: 2005
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Subjects: Homing pigeons