Mystery still surrounds the deaths of dozens of birds in an aviary in a Peterborough park.
More than 30 zebra finches were found dead in the bird house at Central Park in the city over the Christmas break.
The aviary held about 70 finches, along with dozens of other parakeets and budgies, and an investigation was launched after the 35 deaths .
But a post mortem has failed to reveal the cause of death.
Tony Forster, chairman of the Friends Of Central Park said he had heard a break in at the park in December had caused a power cut, meaning heaters had been turned off. He also said he had heard a key was lost meaning the birds could not be fed.
But Kieron King, Peterborough’s principal operations manager for Amey said: “The result of the post mortem carried out by a city vet showed that the body condition of the birds displayed no cause for concern.
“Both of the birds examined had ‘food in the stomach’ and that there were ‘no findings to explain death’.
“The birds are fed 365 days a year. Following an internal interview with the employee overseeing the aviaries, we can confirm that the birds were fed on Christmas Day and Boxing Day.
“The broken key in the lock occurred on Sunday, December 27 and the RSPCA were notified and attended the aviary the following day to assess the birds.
“The three aviaries within Central Park do not and have never housed heaters, so any power lost in the park as a result of a break in would not have had an impact upon the aviaries or the condition of Zebra Finches.”
There have been no further deaths since Christmas.