Media

Tail cameras provide crow’s-eye view of clever tool use

4 October 2007

Observing wild birds this closely in their natural habitat has been one of the final frontiers of ornithological field research.

Dr Christian Rutz

A new technique developed by Oxford University zoologists enables researchers to ‘hitch a ride’ with wild birds and witness their natural and undisturbed behaviour.

The scientists developed miniaturisedvideo cameras with integrated radio-tags that can be carried by wild, free-flying birds. Using this new ‘video-tracking’ technology, they spied on the behaviourof New Caledonian crows, a species renowned for its sophisticated use of tools, recording behavioursnever seen before. A report of the research appears in this week’s Science.

Observing New Caledonian crows in the wild is extremely difficult because they are easily disturbed and live in densely forested, mountainous terrain. ‘Video-tracking’ enabled the Oxford scientists to obtain particularly intimate observations of crow behaviour.

‘Everyone thought that New Caledonian crows use tools mainly to probe into holes and cracks in rotting wood and tree crowns, but we now discovered that they use tools even on the ground,’ said Dr Christian Rutz, from the BehaviouralEcology Research Group at Oxford University’s Department of Zoology. One crow was seen probing leaf litter with grass-like stems – a mode of tool use, and a tool material, that decades of observation with conventional techniques had missed. ‘This discovery highlights the power of our new video-tracking technology’ said Dr Rutz, who leads the group’s field research. ‘This is the first time that wild birds have been tracked in this way, and it has already changed our understanding of New Caledonian crow behaviour.’

For the study, 18 crows were fitted with ‘tailcams’ with each unit weighing about 14 grams – only slightly heavier than a conventional radio-tag. The units were attached to two tail feathers with strips of adhesive tape, and were designed so that they did not adversely affect the bird’s movements, and could be removed by the crows themselves or would detach after a few weeks with the birds’ natural moultingprocess.

‘Observing wild birds this closely in their natural habitat has been one of the final frontiers of ornithological field research,’ said Dr Rutz. ‘Whilst video footage has been taken before using tame, trained birds, it is only now that we have been able to design cameras that are small and light enough to travel with wild birds and let them behave naturally. Potentially, this new video technology could help us to answer some long-standing questions about the ecology and behaviourof many other bird species that are otherwise difficult to study.’

For more information contact Dr Christian Rutz on +44 (0)1865 271179 or email christian.rutz@zoo.ox.ac.uk alternatively contact the University of Oxford Press Office on +44 (0)1865 283877 or email press.office@admin.ox.ac.uk

 

Notes to editors

  • A report of the research, entitled ‘Video Cameras on Wild Birds’ is published in Science Express on Thursday 4 October 2007. The research was undertaken by Dr Christian Rutz, Lucas Bluff, Dr Alex Weir and Professor Alex Kacelnik from the BehaviouralEcology Research Group atOxford University’s Department of Zoology.
  • The researchers were studying the New Caledonian crow (Corvus moneduloides), a species that has attracted attention with its unusually sophisticated use of tools for extracting invertebrates from holes and crevices. The species is endemic to the tropical island of New Caledonia in the South Pacific where fieldwork was conducted.
  • This is the first time that video cameras have been attached to wild birds roaming their natural habitat – previous video footage has used tame, trained birds.
  • Previous studies on New Caledonian crows by the BehaviouralEcology Research Group (headed by Professor Alex Kacelnik)have shown that: tool-related behaviour emerges in juvenilecrows that had no opportunity to learn from others; crows have a preferred way of holding their tools comparable to the way that humans are either right- or left-handed; adult crows can make or select tools of the appropriate length or diameter for experimental tasks; and one crow, at least, can bend and unbend novel material to match task requirements. Further information including photos and videos of tool use at: www.NewCaledonianCrow.com
  • This work was funded by the UK’s Biotechnology and Biological Sciences Research Council (BBSRC). Dr Christian Rutz and Lucas Bluff held Rhodes Scholarships whilst working on the project. Dr Rutz is currently a Junior Research Fellow at Linacre College, Oxford.

Further information