Scientists at the University of Oxford hope a computerised egg will crack open the secrets of how cygnets hatch at Abbotsbury Swannery in Dorset.
Normally a swan lays 4-10 eggs, at two-day intervals, and during this time she will sit on the nest for most of the day to guard her eggs. Only when the last egg has been laid will incubation begin.
This process means that cygnets hatch together and can therefore be better cared for. The mystery is: what happens to the temperature of the eggs?
Professor Chris Perrins, of the Edward Grey Institute of Field Ornithology at the University of Oxford, said: ‘It’s something that’s puzzled us for a long time. Birds don’t normally waste energy and yet some preliminary observations during the laying period indicate that a female swan does keep her eggs at least partly warm some of the time. But since the eggs hatch together, they are not apparently kept warm enough for development to take place. So why use up energy doing it at all? It seems odd. We want to understand in greater detail the amount of heat that a female puts into her eggs during laying and incubation and why and how it’s done.’
To find out, Dr Stephen Ellwood of the Wildlife Conservation Research Unit (WildCRU) at the University of Oxford, used a diamond saw to cut off the top of a dud swan’s egg. He cleaned out the addled contents, partly filled the shell with silicon and then fitted a miniaturised computer inside. The computer has mobile-phone style accelerometers to measure movements up and down, left and right, and backwards and forwards. It can record these movements and changes in temperature eight times a second or more and then transmit these data to a nearby base-station.
Professor David Macdonald, Director of the WildCRU, added: ‘Our mission is to use science to help discover how to conserve species – since the early days of radio-tracking, cutting edge technology has revolutionised our understanding of animal behaviour, and contributed major insights to conservation – we expect this new technology to be as useful to conservation as it is interesting to science.’
Placed into a swan’s nest at Abbotsbury alongside a clutch of normal eggs, scientists and Swannery staff now hope the computerised egg has transmitted enough information to reveal what goes on beneath a swan during nearly two months of laying and sitting and incubation. Computerised leg tags were also fitted to the parent swans using this same nest, as well as to two other pairs, and one individual.
Dr Ellwood said: ‘These kinds of devices make observations that were impossible, possible. People just can’t go into the places that these devices can go.’
Dr Ellwood previously worked on a different monitoring project, where he had the idea of adapting RFID tagging technology, commonly used to prevent shoplifting, to track wild animals. In collaboration with colleagues from the Zoology and Computer Science departments of the University of Oxford, and the Computer Science department at the University of Cambridge, this idea formed part of the ‘Wildsensing’ research project. Through ‘Wildsensing’ Dr Ellwood met Dr Andrew Markham, from Oxford, the designer of the system now used at Abbotsbury, who continues to provide technical support.
The Abbotsbury work is part of a one-year project being funded by the Knowledge Transfer Secondment scheme of the Engineering and Physical Sciences Research Council via Oxford University. The project’s aim is to transfer knowledge from academia into industry so that it can be commercialised and exported across the world. This has the added benefit that it generates a financial return, to the UK, on the initial public funding of research. Dr Ellwood has therefore been working closely with Biotrack of Wareham in Dorset, specialists in the manufacture of animal tracking technologies, in particular on ways of making the technology easy and reliable for people to use.
Abbotsbury has been home for nearly 1,000 years to a colony of mute swans well-used to interaction with Swannery staff and visitors. Dr Ellwood said the birds’ long history of semi-domestication made them particularly suitable for this kind of observational research.
Dave Wheeler, Swanherd at Abbotsbury said: ‘There’s possibly nowhere else in the world that this study could go on without disturbing birds. Here, they are used to our management and we can be intimately close at very sensitive times, throughout nesting and throughout hatching, and they’re very used to that, so applying data loggers and receiving information from them and checking those data loggers is nothing unusual, really. ‘If we didn’t take advantage of this unique situation, where the birds are so tolerant, I think it would be a crime. ‘The knowledge and the data gathered here could be of use in other places.’
Dr Ellwood said he was enjoying working at Abbotsbury Swannery, a place he had previously visited on holiday.
He said: ‘It’s wonderful. It’s