Hedgehogs given GPS 'backpacks' to boost survival rates
Hedgehogs which have been nursed back to health are being fitted with GPS "backpacks" to find out how they go on to survive in the wild.
The 24 hedgehogs, cared for at Shepreth Wildlife Park in Cambridgeshire, will have their movements tracked.
The animals will be released in Suffolk and Cambridgeshire on Wednesday.
Rebecca Willers, chairwoman of Shepreth Wildlife Conservation Charity, hopes the study can eventually boost survival rates of rehabilitated hedgehogs.
The £150 devices weigh just over 1.8oz (50g) and have been designed for the project by Dr David Wallis of Ecometry Technologies.
An inch-square section of spines will be clipped on each creature's back with the battery-powered backpacks then glued on.
This will take place as the hedgehog is coming around from an anaesthetic, which will be administered so the charity's vet can give them a health check.
The tracking device, which uses satellite positioning, will be monitored on a computer.
It will fall off when the animal naturally sheds its spikes in a few months.
Miss Willers hopes the pioneering study will run for a number of years if funding can be found.
"The over-arching aim is to see if hedgehogs survive in the wild after rehabilitation in what is a plastic environment," she said.
"But the most important aspect is to find out if hedgehogs go on to reproduce and if rehabilitation is helping the hedgehog population as a whole.
"In 10 years we want to have a comprehensive guide of the best release sites and methods."
The animals are being set free at both rural and urban sites in Shepreth on the Hertfordshire/Cambridgeshire border, Ely in Cambridgeshire and West Stow and Beck Row in Suffolk.
This year researchers hope to discover if captive hedgehogs revert to their natural behaviour once released.
"The point of this study is to find the best release weights for hibernation and to discover if they are actually going to go into hibernation," said Miss Willers.
Pre-release pens have been set up at the park and are housing the hedgehogs as they get used to living outside.
"We wouldn't be releasing animals if they were not at optimum fitness," said Miss Willers.
"Nothing is being put at risk."
Before the study was finalised, the hedgehogs were put under 24-hour surveillance for two weeks to see if the GPS packs caused any ill-effects.
Volunteers have also been assigned to each location and if an animal stops moving they will investigate.
The £9,500 cost of the research has been funded by the British Hedgehog Preservation Society.
A report published in 2011 said hedgehog numbers were believed to have fallen by a quarter in a decade.