An outbreak of avian malaria has killed more than two thirds of one of Britain’s largest Humboldt penguin colonies.
Keepers at Dudley Zoo in the West Midlands were left “heartbroken” after about 50 of the 69 birds in their care succumbed to the parasitic disease.
On Saturday, the zoo said the outbreak was “still ongoing” and about 70 per cent of the colony had died.
Penguins are particularly susceptible to avian malaria, which is transmitted through the bite of infected mosquitos. It cannot be passed from animals to humans.
Despite the best efforts of vets and zoo staff, the outbreak could not be stopped, a representative said.
Keepers are now working to treat the remaining birds and put in place preventative measures to “avoid tragedy happening again”, it said.
“We are all heartbroken with the huge loss in Penguin Bay and it’s been an especially distressing time for our bird team who have devoted years to their care,” said the zoo’s director, Derek Grove.
The zoo said it has had a successful breeding programme for Humboldt penguins for 30 years.
Starting with five hand-reared chicks in 1991, it had gone on to breed one of the largest self-sustained colonies in the country, it said.
Mr Grove said penguins do not have natural resistance to the disease and it is not easily identifiable on tests, making the outbreak harder to control.
“Thankfully, occurrences like this are rare and in over three decades we’ve never experienced anything like it before,” he said.
“We do not know if last year’s unusual weather pattern has played a part, with wet and muggy weather not only impacting the penguins’ moulting season but also increasing the risk of mosquitos. But what we do know is we now need to focus on continuing to treat the remaining birds and putting in place additional preventative measures to avoid this tragedy happening again.”